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GGMT-2019 The 20th WMO/IAEA Meeting on Carbon Dioxide, Other Greenhouse Gases, and Related Measurement Techniques

Content

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Program

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GGMT 2019 – FINAL PROGRAM

ADVISORY COMMITTEE ORGANIZING COMMITTEE

GGMT ADVISORY COMMITTEE

Sergey Assonov (International Atomic Energy Agency, Austria) Andrew Crotwell (NOAA Earth System Research Laboratory, USA) Ed Dlugokencky (NOAA Earth system Research Laboratory, USA) Luciana Gatti (National Institute for Space Research (INPE), Brazil) David Griffith (University of Wollongong, Australia) Brad Hall (NOAA Earth System Research Laboratory, USA) Armin Jordan (Max Plank Institute for Biogeochemistry, Germany) Paul Krummel (CSIRO Marine and Atmospheric Research, Australia) Haeyoung Lee (KMA/National Institute of Meteorological Sciences, Republic of Korea) Zoe Loh (CSIRO Marine and Atmospheric Research, Australia) Andrew Manning (University of East Anglia, UK) Heiko Moossen (Max Plank Institute for Biogeochemistry, Germany) Martin Steinbacher (Empa, Switzerland) Jocelyn Turnbull (GNS Science, New Zealand) Yousuke Sawa (Japan Meteorological Agency, Japan) Alex Vermeulen (Lund University, Sweden) Ray Weiss (Scripps Institute of Oceanography, USA)

KOREA ORGANIZING COMMITTEE

Sang-Boom Ryoo (Chair, KMA/NIMS) Young-San Park (KMA/NIMS) Taeyoung Goo (KMA/NIMS) Seoung-Woon Noh (KMA) Haeyoung Lee (KMA/NIMS) Sunyoung Park (Kyungpook National University) Jeongsoon Lee (Korea Research Institute of Standards and Sciences) Sujong Jeong (Seoul National University) Jinho Ahn (Seoul National University)

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OVERVIEW

TIME Sep. 1 (Sun) Sep. 2 (Mon) Sep. 3 (Tue)

8-9

9-10

10-11

11-12

12-13

13-14

14-15

15-16

16-17

17-18

18-19

19-20

SAG-GHG meeting

(closed meeting) (14:00-17:30)

Registration(Ι)

on the 6th floor of Banquet Building

(13:00-18:00)

ICE Breaker

at The Lounge of Main Building (18:00-20:00)

Registration(ΙΙ) (8:00-9:00)

Oral Presentation

and Discussion session

in the Cristal Ballroom, Banquet Building

(9:00-15:40)

Vendor’s exhibition

in Emerald Room,

Banquet Building

&

Poster session

in the lobby (9:00-18:00)

Oral Presentation


(8:30-16:20)


&

Poster session (9:00-18:00)

Lunch (12:00-13:20)

Lunch* (12:00-13:20)

ICE Breaker


Banquet (18:00-20:00)

* Two vendor’s presentation from 13:00

Side meeting

in the Charlotte Room

(17:00-19:00)

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OVERVIEW

TIME Sep. 1 (Sun) Sep. 2 (Mon) Sep. 3 (Tue)

8-9

9-10

10-11

11-12

12-13

13-14

14-15

15-16

16-17

17-18

18-19

19-20

SAG-GHG meeting

(closed meeting) (14:00-17:30)

Registration(Ι)

on the 6th floor of Banquet Building

(13:00-18:00)

ICE Breaker


Registration(ΙΙ) (8:00-9:00)

Oral Presentation


in the Cristal Ballroom, Banquet Building

(9:00-15:40)


in Emerald Room,

Banquet Building

&

Poster session


Oral Presentation


(8:30-16:20)


&


Lunch (12:00-13:20)

Lunch* (12:00-13:20)

ICE Breaker


Banquet (18:00-20:00)


Side meeting

in the Charlotte Room

(17:00-19:00)


OVERVIEW

TIME Sep. 4 (Wed) Sep. 5 (Thu) Sep. 6 (Fri)

8-9

9-10

10-11

11-12

12-13

13-14

14-15

15-16

16-17

17-18

18-19

19-20


in Emerald Room,

Banquet Building

&

Poster session


Oral Presentation


(8:30-17:00)


&


Lunch* (12:00-13:20)

Lunch (12:10-13:30)

<Excursion> Jeju Gosan GAW station & Jeju

Suwolbong Geopark

(8:30-12:30) Oral

Presentation and Discussion

session

(8:30-16:20)


Side meeting

(16:20-17:00)

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FLOOR PLAN

Floor plan for GGMT-2019 (6th floor of Banquet Building, Lotte Hotel Jeju)

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FLOOR PLAN

Floor plan for GGMT-2019 (6th floor of Banquet Building, Lotte Hotel Jeju)


SOCIAL EVENTS

ICEBREAKER (& REGISTRATION)

SUNDAY, SEPTEMBER 1

REGISTRATION: 13:00 – 18:00

6th floor of Banquet Building, Lotte Hotel Jeju

ICEBREAKER: 18:00 – 20:00

The Lounge, 6th floor of Banquet Building, Lotte Hotel Jeju

Please complete the registration before participating in the icebreaker.

BANQUET

TUESDAY, SEPTEMBER 3, 18:00 – 20:00

Cristal Ballroom, 6th floor of Banquet Building, Lotte Hotel Jeju

EXCURSION

FRIDAY, SEPTEMBER 6, 8:30 - 12:30

Meeting point: Main Entrance, 8th floor of Main Building, Lotte Hotel Jeju

Use the bus to Jeju Gosan GAW station & Jeju Suwolbong Geopark for 1 hour

Main Building Banquet Building

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MONDAY, SEPTEMBER 2, 2019

8:00-9:00 Registration & Poster installation

9:00-9:15 Welcome speech & Introduction of NIMS GHG activities by Sangwon Joo

9:15-9:35 Updates from WMO by Oksana Tarasova

9:35-10:00 Group photo & Coffee break

Session 1 Quality assurance of greenhouse gas measurements (including reference standards, comparison activities and good practices) Chair: Oksana Tarasova

10:00-12:00

T1 (20’) Towards an International Reference Network for Greenhouse Gases by Arlyn Andrews T2 (20’) Labelling process in ICOS atmosphere and quality control steps towards the first

official data releases by Leonard Rivier T3 (20’) Can your network stand the test of time? by Colm Sweeney T4 (20’) Update on CO2, CO, and N2O calibration scales by Brad Hall T5 (20’) Implementation of the WMO CO2 X2019 scale revision by Andrew Crotwell T6 (20’) Towards an on-going comparison on the accuracy of standards and scales for

atmospheric CO2 measurement by Robert Wielgosz

12:00-13:20 Lunch

Session 1 Quality assurance of greenhouse gas measurements (including reference standards, comparison activities and good practices) Chair: Alex Vermeulen

13:20-14:00 T7 (20’) Training, twinning, and capacity building in support of greenhouse gas observations

in data sparse regions by Martin Steinbacher T8 (20’) Recent Activities and Achievements of WCC-Empa by Christoph Zellweger

14:00-15:00

Discussion Agenda: Calibrations of GAW measurement, CO2, CH4 Refer to the GGMT report Chapter 1: CALIBRATION OF GAW MEASUREMENTS (Lead: Martin Steinbacher) Chapter 3: SPECIFIC REQUIREMENTS FOR CO2 CALIBRATION (Lead Andrew Crotwell) Chapter 7: SPECIFIC REQUIREMENTS FOR CH4 CALIBRATION (Lead: Ed Dlugokencky)

15:00-15:40 Speed talk for poster session of site and network updates (5 min for 8) Chair: Young-san Park

15:40-16:00 Coffee break

16:00-18:00 Poster session at Lobby From 17:00 Side meeting Strategies to assess and improve the measurement compatibility for isotope ratio in atmospheric CH4

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TUESDAY, SEPTEMBER 3, 2019

Session 1 Quality assurance of greenhouse gas measurements (including reference standards, comparison activities and good practices) Chair : Christoph Zellweger

8:30-9:50

T9 (20’) Comparison of in situ measurements of CO2 and CH4 at the Cape Grim Baseline Station by Zoe Loh

T10 (20’) Comparisons of non- CO2 trace gas measurements between AGAGE and NOAA at common sites by Paul Krummel

T11 (20’) Standard of greenhouse gases measurement by Jeongsoon Lee T12 (20’) Breakthrough in Negating the Impact of Adsorption in Gas Reference Materials by

Paul Brewer

9:50-10:30

Discussion Agenda: N2O, SF6, CO Refer to the GGMT report Chapter 8: SPECIFIC REQUIREMENTS FOR N2O CALIBRATION (Lead: Brad Hall) Chapter 9: SPECIFIC REQUIREMENTS FOR SF6 CALIBRATION (Lead: Haeyoung Lee) Chapter 10: SPECIFIC REQUIREMENTS FOR CO CALIBRATION (Lead: Andrew Crotwell)

10:30-10:40 Discussion Agenda: The 7th Round Robin Experiment Chair: Brad Hall

10:40-11:00 Coffee Break

Session 2 Data products and utilization of the observations Chair : Zoe Loh

11:00-12:00

T13 (20’) Potential Bias in Preliminary Estimates of Global LLGHG Trends by Edward Dlugokencky

T14 (20’) Taking in-situ greenhouse gas information into the big data era by Alex Vermeulen

T15 (20’) ObsPack 5 Years Later: Where Are We Now and Where Are We Going? By Kenneth Schuldt

12:00-13:20 Lunch, Two vendor ’s presentations from 13:00 (each 10’)

13:20-14:00

Discussion Agenda: Determination of uncertainty, Data management, archiving and distributions Refer to the GGMT report Chapter 2: RECOMMENDATIONS FOR THE DETERMINATION OF UNCERTAINTY (Lead:

Armin Jordan and Andrew Crotwell) Chapter 16: RECOMMENDATIONS FOR DATA MANAGEMENT, ARCHIVING, AND

DISTRIBUTION (Lead: Alex Vermeulen)

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Session 3 Advances in the traditional greenhouse gas measurement techniques Chair : Doug Worthy

14:00-15:00

T16 (20’) The evolution of AGAGE: Overview of improved measurement technologies for the quantification of GHG and ODS emissions by Ray Weiss

T17 (20’) A Detachable Trap Preconcentrator with a Gas Chromatograph-Mass Spectrometer for the Analysis of Trace Halogenated Greenhouse Gases by Jeong-Sik Lim

T18 (20’) Methane Source Localisation and Emission Quantification at Facility Scale Using Multi-beam Open Path Laser Dispersion Spectroscopy by Mohammed Belal

Session 4 Emerging Observation Techniques including low-cost sensors, Remote Sensing and Integration of Observations Chair : Ann Stavert

15:00-16:20

T19 (20’) Open path FTIR measurements of greenhouse gas concentrations and fluxes in the atmosphere over kilometre pathlengths by David Griffith

T20 (20’) Study of error and sensitivity of short-term variation in XCO2 observed by Anmyeondo station by Young-Suk Oh

T21 (20’) Principle, calibration and preliminary results of ground-based atmospheric CO2 monitoring instrument using spatial heterodyne spectroscopy by Zhiwei Li.

T22 (20’) Trace gas measurements at the U.S. Southern Great Plains DOE Atmospheric Radiation Measurement Facility using an in situ FTIR: lesson learned after a 6-year deployment by Sebastien Biraud

16:20-18:00 Coffee break & Poster session at Lobby

18:00-20:00 Banquet at Cristal Ballroom



Session 1 Quality assurance of greenhouse gas measurements (including reference standards, comparison activities and good practices) Chair : Christoph Zellweger

8:30-9:50

T9 (20’) Comparison of in situ measurements of CO2 and CH4 at the Cape Grim Baseline Station by Zoe Loh

T10 (20’) Comparisons of non- CO2 trace gas measurements between AGAGE and NOAA at common sites by Paul Krummel

T11 (20’) Standard of greenhouse gases measurement by Jeongsoon Lee T12 (20’) Breakthrough in Negating the Impact of Adsorption in Gas Reference Materials by

Paul Brewer

9:50-10:30

Discussion Agenda: N2O, SF6, CO Refer to the GGMT report Chapter 8: SPECIFIC REQUIREMENTS FOR N2O CALIBRATION (Lead: Brad Hall) Chapter 9: SPECIFIC REQUIREMENTS FOR SF6 CALIBRATION (Lead: Haeyoung Lee) Chapter 10: SPECIFIC REQUIREMENTS FOR CO CALIBRATION (Lead: Andrew Crotwell)

10:30-10:40 Discussion Agenda: The 7th Round Robin Experiment Chair: Brad Hall


Session 2 Data products and utilization of the observations Chair : Zoe Loh

11:00-12:00

T13 (20’) Potential Bias in Preliminary Estimates of Global LLGHG Trends by Edward Dlugokencky

T14 (20’) Taking in-situ greenhouse gas information into the big data era by Alex Vermeulen

T15 (20’) ObsPack 5 Years Later: Where Are We Now and Where Are We Going? By Kenneth Schuldt

12:00-13:20 Lunch, Two vendor ’s presentations from 13:00 (each 10’)

13:20-14:00

Discussion Agenda: Determination of uncertainty, Data management, archiving and distributions Refer to the GGMT report Chapter 2: RECOMMENDATIONS FOR THE DETERMINATION OF UNCERTAINTY (Lead:

Armin Jordan and Andrew Crotwell) Chapter 16: RECOMMENDATIONS FOR DATA MANAGEMENT, ARCHIVING, AND

DISTRIBUTION (Lead: Alex Vermeulen)

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WEDNESDAY, SEPTEMBER 4, 2019

8:30-9:00

Discussion Agenda: remote sensing, ship measurement, new and emerging technique Refer to the GGMT report Chapter 13: RECOMMENDATIONS FOR GROUND-BASED REMOTE SENSING TECHNIQUES

(Lead: David Griffith) Chapter 14: RECOMMENDATIONS FOR AIR MEASUREMENTS OF CO2 ON SHIPS (Lead:

TBA) Chapter 15 : NEW AND EMERGING TECHNIQUES (Lead: David Griffith)

Session 5 Measurements and quality assurance for 14C, O2/N2 and related tracers Chair : Anna Karion

9:00-10:20

T23 (20’) Atmospheric 14CO2 Southern Hemisphere latitudinal gradient over recent decades by Rachel Corran

T24 (20’) Inter-comparison of O2/N2 scales among AIST, NIES, TU, and SIO using primary standard mixtures with less than 5 per meg uncertainty for δ(O2/N2) by Nobuyuki Aoki

T25 (20’) Quantifying the span sensitivity of interferometric oxygen measurements by Ralph Keeling

T26 (20’) Outline of the UEA/ENV & CAMS/CMA Collaborative Research Project: Establishing a high Precision atmospheric Oxygen network in China (EPOCH) by Lingxi Zhou


Session 6 Quality assurance of the measurements of the stable isotopes (including reference standards, comparison activities and good practices) Chair: Paul Brewer

10:40-12:00

T27 (20’) Challenges in maintaining the artefact-based stable isotope scale for δ13C with the aim to address GAW-WMO uncertainty requirements by Sergey Assonov

T28 (20’) Assuring quality in the measurement and reporting of stable isotope measurements of atmospheric carbon dioxide by Colin Allison

T29 (20’) Comparison of isotope ratio measurement capabilities for CO2 isotopes: Sample preparation and characterization by isotope ratio infrared spectroscopy and mass-spectrometry by Joele Viallon

T30 (20’) Strategies to assess and reduce current inter-laboratory differences in δ 13C-CH4 and δ 2H-CH4 measurements in air samples by Peter Sperlich

12:00-13:20 Lunch, Two vendor's presentations from 13:00 (each 10')

Oral Presentation


(8:30-16:20)

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8:30-9:00

Discussion Agenda: remote sensing, ship measurement, new and emerging technique Refer to the GGMT report Chapter 13: RECOMMENDATIONS FOR GROUND-BASED REMOTE SENSING TECHNIQUES

(Lead: David Griffith) Chapter 14: RECOMMENDATIONS FOR AIR MEASUREMENTS OF CO2 ON SHIPS (Lead:

TBA) Chapter 15 : NEW AND EMERGING TECHNIQUES (Lead: David Griffith)

Session 5 Measurements and quality assurance for 14C, O2/N2 and related tracers Chair : Anna Karion

9:00-10:20

T23 (20’) Atmospheric 14CO2 Southern Hemisphere latitudinal gradient over recent decades by Rachel Corran

T24 (20’) Inter-comparison of O2/N2 scales among AIST, NIES, TU, and SIO using primary standard mixtures with less than 5 per meg uncertainty for δ(O2/N2) by Nobuyuki Aoki

T25 (20’) Quantifying the span sensitivity of interferometric oxygen measurements by Ralph Keeling

T26 (20’) Outline of the UEA/ENV & CAMS/CMA Collaborative Research Project: Establishing a high Precision atmospheric Oxygen network in China (EPOCH) by Lingxi Zhou


Session 6 Quality assurance of the measurements of the stable isotopes (including reference standards, comparison activities and good practices) Chair: Paul Brewer

10:40-12:00

T27 (20’) Challenges in maintaining the artefact-based stable isotope scale for δ13C with the aim to address GAW-WMO uncertainty requirements by Sergey Assonov

T28 (20’) Assuring quality in the measurement and reporting of stable isotope measurements of atmospheric carbon dioxide by Colin Allison

T29 (20’) Comparison of isotope ratio measurement capabilities for CO2 isotopes: Sample preparation and characterization by isotope ratio infrared spectroscopy and mass-spectrometry by Joele Viallon

T30 (20’) Strategies to assess and reduce current inter-laboratory differences in δ 13C-CH4 and δ 2H-CH4 measurements in air samples by Peter Sperlich

12:00-13:20 Lunch, Two vendor's presentations from 13:00 (each 10')

Oral Presentation


(8:30-16:20)



Session 6 Quality assurance of the measurements of the stable isotopes (including reference standards, comparison activities and good practices) Chair: Jinho Ahn

13:20-14:00

T31 (20’) JRAS-06: Scale maintenance and keeping up with changing stable isotopic reference materials by Heiko Moossen

T32 (20’) JRAS-06 or bust! The INSTAAR Stable Isotope Lab revises its ties to primary reference materials and releases a revised data set of stable isotopes of CO2 by Sylvia Michel

14:00-15:00 (Parallel)

Discussion Agenda: Stable isotope (Meeting room: Cristal Ballroom) Refer to the GGMT report Chapter 4: SPECIFIC REQUIREMENTS FOR STABLE ISOTOPE CALIBRATION (Lead: Sylvia

Michel)

Discussion Agenda O2/N2, H2, Radiocarbon (Meeting room: Charlotte room) Refer to the GGMT report Chapter 5: SPECIFIC REQUIREMENTS FOR THE CALIBRATION OF RADIOCARBON IN

TRACE GASES (Lead: Jocelyn Turnbull) Chapter 6: SPECIFIC REQUIREMENTS FOR O2/N2 CALIBRATION (Lead: Ralph Keeling) Chapter 11: SPECIFIC REQUIREMENTS FOR H2 CALIBRATION (Lead: Armin Jordan)

Session 7 Sites and network update Chair: Jocelyn Turnbull

15:00-16:20

T33 (20’) Design and implementation of an enhanced observation network in New Zealand by Gordon Brailsford

T34 (20’) Evolving Greenhouse gases observational network in India by Yogesh Tiwari T35 (20’) Collection of CO2 measurements in Europe for the study of the drought of

Summer 2018 by Michel Ramonet T36 (20’) Observation of atmospheric carbon monoxide at the background stations in

China by Shuangxi Fang

16:20-18:00 Coffee break & Poster session at Lobby

16:20-17:00 Side meeting Capacity development towards wider use of stable isotopic techniques for source attribution of greenhouse gases in the atmosphere

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THURSDAY, SEPTEMBER 5, 2019

Session 8 Urban Observations and Networks Chair: Luciana Gatti

8:30-09:50

T37 (20’) CO2 and air quality over megacity: a case study of Seoul, Korea by Sojung Sim T38 (20’) Carbon Dioxide Enhancement over Seoul Capital Area from Space and Surface

Measurements by Chaerin Park T39 (20’) High precision CO2 measurement at Beijing-Tianjin-Hebei city cluster in China by

Bo Yao T40 (20’) Updates from the Los Angeles Megacities Carbon Project by Jooil Kim


Session 8 Urban Observations and Networks Chair: Jooil Kim

10:10-11:30

T41 (20’) Development of A Full Carbon Budget for Auckland, New Zealand by Jocelyn Turnbull

T42 (20’) Progress from the Indianapolis Flux (INFLUX) tower-based urban greenhouse gas network by Natasha Miles

T43 (20’) Greenhouse gas observations from the Northeast Corridor tower network by Anna Karion

T44 (20’) Long-term monitoring and modelling of atmospheric CH4 to track its trend and to assess a detailed spatially explicit emission mapping the Greater Toronto and Hamilton Area, Canada by Felix Vogel

11:30-12:10

Discussion Agenda: networks in Areas of high density emission Refer to the GGMT report Chapter 12: RECOMMENDATIONS FOR GREENHOUSE GAS NETWORKS IN AREAS OF

HIGH DENSITY EMISSIONS (Lead: Felix Vogel)

12:10-13:30 Lunch

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Session 8 Urban Observations and Networks Chair: Luciana Gatti

8:30-09:50

T37 (20’) CO2 and air quality over megacity: a case study of Seoul, Korea by Sojung Sim T38 (20’) Carbon Dioxide Enhancement over Seoul Capital Area from Space and Surface

Measurements by Chaerin Park T39 (20’) High precision CO2 measurement at Beijing-Tianjin-Hebei city cluster in China by

Bo Yao T40 (20’) Updates from the Los Angeles Megacities Carbon Project by Jooil Kim


Session 8 Urban Observations and Networks Chair: Jooil Kim

10:10-11:30

T41 (20’) Development of A Full Carbon Budget for Auckland, New Zealand by Jocelyn Turnbull

T42 (20’) Progress from the Indianapolis Flux (INFLUX) tower-based urban greenhouse gas network by Natasha Miles

T43 (20’) Greenhouse gas observations from the Northeast Corridor tower network by Anna Karion

T44 (20’) Long-term monitoring and modelling of atmospheric CH4 to track its trend and to assess a detailed spatially explicit emission mapping the Greater Toronto and Hamilton Area, Canada by Felix Vogel

11:30-12:10

Discussion Agenda: networks in Areas of high density emission Refer to the GGMT report Chapter 12: RECOMMENDATIONS FOR GREENHOUSE GAS NETWORKS IN AREAS OF

HIGH DENSITY EMISSIONS (Lead: Felix Vogel)

12:10-13:30 Lunch



Session 9 Observations from the mobile platforms (aircraft, drone, balloon, etc) and over/in the ocean Chair: Dagmar Kubistin

13:30-15:30

T45 (20’) Comparisons of AirCore vertical profiles of greenhouse gases from an intensive RINGO campaign at Sodankylä, Finland by Huilin Chen

T46 (20’) Continuous airborne measurements of CO2, CH4, H2O and CO in South Korea by Shanlan Li

T47 (20’) Light Rail-Based Monitoring of Greenhouse Gases Across An Urban Area by Edward Orr

T48 (20’) Mobile real-time measurement of methane in Beijing: methodology development and application by Wanqi Sun

T49 (20’) Statistical characterization of atmospheric CO2 in airport proximity from the CONTRAIL commercial aircraft measurements by Taku Umezawa

T50 (20’) Implementing Atmospheric CO2 Measurements from Ships of Opportunity by Rik Wanninkhof

15:30-16:00

Discussion Agenda: Recommendations WMO/GAW network Refer to the GGMT report Chapter 17: RECOMMENDATIONS FOR THE COOPERATIVE WMO/GAW NETWORK (Lead :

Oksana Tarasova)

16:00-17:00 Expert group recommendation (Lead: TBA, Rapporteur: TBA)


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POSTER SESSION

Session 1. Quality assurance of greenhouse gas measurements (including reference standards, comparison activities and good practices)

P01 The inter-comparison activities of WCC-SF6 during 8 years by Haeyoung Lee

P02 Travelling cylinders as a quality control tool in ICOS atmospheric station network by Hermanni Aaltonen

P03 WCC and QA/SAC activities by JMA by Teruo Kawasaki

P04 Uncertainty analysis of calibration measurements made by the ICOS Flask and Calibration Laboratory by Armin Jordan

P05 Development of dimethyl sulfide primary reference gas mixtures for global atmospheric monitoring by Mi Eon Kim

P06 New calibration system for methane and carbon dioxide at JMA by Kentaro Ishijima

P07 Influences of thermal fractionation and adsorption on CO2 standard mixture gravimetrically prepared using multiple steps by Nobuyuki Aoki

P08 GHGs data comparison between NIES observation network (aircrafts, stations and ships) in the Asian-Pacific region and GOSAT by Shohei Nomura

P09 The Atmospheric Pressure Effect on N2O Analysis and the Use of a Exhaust Chamber to Minimize this Effect by Caio Correia

P10 Ambient air performance of N2O Los Gatos analysers at Hohenpeissenberg by Dagmar Kubistin

P11 Results of a Long-Term International Comparison of Greenhouse Gas and Isotope Measurements at the Global Atmosphere Watch (GAW) Station in Alert, Nunavut, Canada by Doug Worthy

P12 How to deal with water vapor for Greenhouse gas dry mole fraction measurement with Cavity Enhanced Spectrometer: water vapor correction vs Nafion dryer by Olivier Laurent

P13 Metrological performance assessment of different Cavity Enhanced Spectrometer to measure atmospheric nitrous oxide by Olivier Laurent

P14 Laboratory Investigation of CO2 Biases Related to Water Vapor Surface Adsorption in Air Samples Stored in Glass Flasks by Don Neff

19


POSTER SESSION

Session 1. Quality assurance of greenhouse gas measurements (including reference standards, comparison activities and good practices)

P01 The inter-comparison activities of WCC-SF6 during 8 years by Haeyoung Lee

P02 Travelling cylinders as a quality control tool in ICOS atmospheric station network by Hermanni Aaltonen

P03 WCC and QA/SAC activities by JMA by Teruo Kawasaki

P04 Uncertainty analysis of calibration measurements made by the ICOS Flask and Calibration Laboratory by Armin Jordan

P05 Development of dimethyl sulfide primary reference gas mixtures for global atmospheric monitoring by Mi Eon Kim

P06 New calibration system for methane and carbon dioxide at JMA by Kentaro Ishijima

P07 Influences of thermal fractionation and adsorption on CO2 standard mixture gravimetrically prepared using multiple steps by Nobuyuki Aoki

P08 GHGs data comparison between NIES observation network (aircrafts, stations and ships) in the Asian-Pacific region and GOSAT by Shohei Nomura

P09 The Atmospheric Pressure Effect on N2O Analysis and the Use of a Exhaust Chamber to Minimize this Effect by Caio Correia

P10 Ambient air performance of N2O Los Gatos analysers at Hohenpeissenberg by Dagmar Kubistin

P11 Results of a Long-Term International Comparison of Greenhouse Gas and Isotope Measurements at the Global Atmosphere Watch (GAW) Station in Alert, Nunavut, Canada by Doug Worthy

P12 How to deal with water vapor for Greenhouse gas dry mole fraction measurement with Cavity Enhanced Spectrometer: water vapor correction vs Nafion dryer by Olivier Laurent

P13 Metrological performance assessment of different Cavity Enhanced Spectrometer to measure atmospheric nitrous oxide by Olivier Laurent

P14 Laboratory Investigation of CO2 Biases Related to Water Vapor Surface Adsorption in Air Samples Stored in Glass Flasks by Don Neff


POSTER SESSION

Session 2. Data products and utilization of the observations

P15 Estimation of greenhouse gas emission factors based on observed covariance of CO2, CH4, N2O and CO mole fractions by Laszlo Haszpra

P16 Operation of new WDCGG website and started of satellite data collection by Atsuya Kinoshita

P17 Enhanced terrestrial carbon uptake over South Korea revealed by atmospheric CO2 measurements by Jeongmin Yun

P18 Comparison of regional simulation of terrestrial CO2 flux from the updated version of CarbonTracker Asia (CTA) with FLUXCOM and other inversions over East Asia by Samuel Takele Kenea

P19 Recent GAW activities of KMA by Yuwon Kim

P20 Abrupt changes of atmospheric CO2 during the last glacial termination and the Common Era by Jinho Ahn

P21 Introduction of Ganseong Global Climate Change Monitoring Station of Ministry of Environment, Korea by Taekyu Kim

Session 3. Advances in the traditional greenhouse gas measurement techniques

P22 The Macquarie Island high precision CO2 record - Calculating uncertainties and exploring trends by Ann Stavert

P23 Development of Novel Trace Methane and Trace Carbon Dioxide Analyzers - Performance Evaluation Studies and Results of Field Deployment by Graham Leggett

P24 Development of a new flask-air analysis system for the Global Greenhouse Gas Reference Network by Andrew Crotwell

P25 Working standard gas saving system for in-situ CO2 and CH4 measurements and calculation method for concentrations and their uncertainty by Motoki Sasakawa

P26 The ICOS automated flask sampler by Markus Eritt

P27 Update on measurements of N2O and CO at the Cape Grim Baseline Air Pollution Station: commissioning of a new high precision in situ analyser by E-A. Guerette

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POSTER SESSION

Session 4. Emerging Observation Techniques including low-cost sensors

P28 Performance analysis of Spatial Heterodyne Spectroscopy on column-averaged carbon dioxide observation by Ye Hanhan

Session 5. Remote Sensing & Integration of Observations

P29 Contrasting the differences in CO2 atmospheric growth over Korea with global patterns by Lev Labzovskii

P30 Quality analysis of on-orbit observation data of Greenhouse gases Monitoring Instrument on GaoFeng-5 satellite by Hailiang SHI

P31 Observing patterns of CO2 and air pollutants of cities using satellite data by Hayoung Park

Session 6. Measurements and quality assurance for 14C, O2/N2 and related tracers

P32 14CO2 observations in atmospheric CO2 at Anmyeondo GAW station, Korea:implication for fossil fuel CO2 and emission ratios by Haeyoung Lee

P33 Distinguishing Artifacts from Real Variability in Airborne Measurements of δ(Ar/N2) by Eric Morgan

P34 Trend in atmospheric CO2 concentrations and carbon isotopic compositions observed at a regional background site in East Asia by Hyeri Park

P35 European atmospheric 14CO2 activities within the ICOS RI network by Samuel Hammer

Session 7. Quality assurance of the measurements of the stable isotopes (including reference standards, comparison activities and good practices)

P36 Five years of δ13C(CO2) measurements from an in situ Fourier transform infrared trace gas and isotope analyser at Lauder, New Zealand by Dan Smale

P37 The effect of phosphoric acid on carbon dioxide standard gas evolution by Jun Sonobe

P38 Assessment of an Isotope Ratio Infrared Spectrometer to measure isotope ratios of carbon dioxide in air under laboratory conditions and at Baring Head, New Zealand by Peter Sperlich

P39 Development of a Quality Assurance Scheme for stable isotope measurements in agreement with the GAW Quality Assurance Principles by Sergey Assonov

P40 Characterisation of optical isotope analysers for carbon dioxide in the framework of EMPIR project SIRS by Ivan Prokhorov

21


POSTER SESSION

Session 4. Emerging Observation Techniques including low-cost sensors

P28 Performance analysis of Spatial Heterodyne Spectroscopy on column-averaged carbon dioxide observation by Ye Hanhan

Session 5. Remote Sensing & Integration of Observations

P29 Contrasting the differences in CO2 atmospheric growth over Korea with global patterns by Lev Labzovskii

P30 Quality analysis of on-orbit observation data of Greenhouse gases Monitoring Instrument on GaoFeng-5 satellite by Hailiang SHI

P31 Observing patterns of CO2 and air pollutants of cities using satellite data by Hayoung Park

Session 6. Measurements and quality assurance for 14C, O2/N2 and related tracers

P32 14CO2 observations in atmospheric CO2 at Anmyeondo GAW station, Korea:implication for fossil fuel CO2 and emission ratios by Haeyoung Lee

P33 Distinguishing Artifacts from Real Variability in Airborne Measurements of δ(Ar/N2) by Eric Morgan

P34 Trend in atmospheric CO2 concentrations and carbon isotopic compositions observed at a regional background site in East Asia by Hyeri Park

P35 European atmospheric 14CO2 activities within the ICOS RI network by Samuel Hammer

Session 7. Quality assurance of the measurements of the stable isotopes (including reference standards, comparison activities and good practices)

P36 Five years of δ13C(CO2) measurements from an in situ Fourier transform infrared trace gas and isotope analyser at Lauder, New Zealand by Dan Smale

P37 The effect of phosphoric acid on carbon dioxide standard gas evolution by Jun Sonobe

P38 Assessment of an Isotope Ratio Infrared Spectrometer to measure isotope ratios of carbon dioxide in air under laboratory conditions and at Baring Head, New Zealand by Peter Sperlich

P39 Development of a Quality Assurance Scheme for stable isotope measurements in agreement with the GAW Quality Assurance Principles by Sergey Assonov

P40 Characterisation of optical isotope analysers for carbon dioxide in the framework of EMPIR project SIRS by Ivan Prokhorov


POSTER SESSION

P41 Isotope Ratio Stability of CO2 Mixtures in Natural Air by Megumi Isaji

P42 Development of international N2O reference materials for site preference measurements by Joanna Rupacher

P43 How good are our measurements of δ13C-CH4? By Sylvia Michel

P44 Calibration Methodology for the Scripps 13C/12C and 18O/16O stable isotope program 1992-2018 by Keeling Ralph

P45 NIWA's δ13C-CO2 measurement programme: Twenty years of monitoring in New Zealand and Antarctica by Rowena Moss

P46 Multipoint normalization of δ18O of water against the VSMOW2-SLAP2 scale with an uncertainty assessment by Taewan Kim

Session 8. Isotope Measurement Techniques

P47 Developing a system to measure nitrous oxide isotopomers in air by Peter Sperlich

P48 Optical method for clumped isotope measurements - the case of carbon dioxide by Ivan Prokhorov

P49 A cryogen-free automated measurement system of stable carbon isotope ratio of atmospheric methane by Taku Umezawa

P50 Measuring stables isotopes of CO2 (13C and 17,18O) in vertical profiles over the Amazon by Raiane A.L.Neves

P51 On the performance of simultaneous measurements of δ13C-CO2, δ18O-CO2 and δ17O-CO2 by Quantum Cascade Dual-Laser Absorption Spectrometry in whole air atmospheric samples from Lutjewad station, the Netherlands by Bert A. Scheeren

22


POSTER SESSION

Session 9. Sites and network update

P52 Pha Din GAW regional station and development orientation of climate change observing network in VietNam by Thi Quynh Hoa Vu

P53 Where is the missing CO2? A regional multi-species approach to trace the fate of atmospheric CO2 in Fiordland National Park, New Zealand by Peter Sperlich

P54 Atmospheric trace gas observations: Latest update from the Cape Point station by Casper Labuschagne

P55 High frequency measurements of atmospheric HFCs at a regional monitoring site in East Asia and the implications for regional emissions by Sunyoung Park

P56 GHG Vertical Profiles Measurement Program in the Amazon by Luciana Gatti

P57 Background Concentrations of CO2, CO and N2O in Brazilian Coast by Luciano Marani

P58 Study of long term SF6 mole fractions in Amazon and Brazilian Coast by Luana Basso

P59 Long Term CH4 measurements in Amazon and Brazilian Coast by Luana Basso

Session 10. Urban Observations and Networks

P60 Observed and simulated urban CO2 behavior around Jakarta megacity by Masahide Nishihashi

P61 MExico city's Regional Carbon Impacts (MERCI- CO2): combining high precision surface monitoring, with low-costs sensors, and total column measurements by Michel Ramonet

Session 11. Observations from the mobile platforms (aircraft, drone, balloon, etc)

P62 Characterising Methane Emissions using a Twin-Otter Airborne Platform by James France

P63 The Aircore system and campaign for vertical profile measurements of greenhouse gases in China by Miao Liang

P64 IAGOS-CORE and IAGOS-CARIBIC greenhouse gas observations from commercial airliners by Christoph Gerbig

P65 Pilot study of Unmanned Aerial Vehicles for sampling water vapor and water isotopes at high-latitudes provides implications for other trace gas sampling by Bruce Vaughn


Oral Session


POSTER SESSION

Session 9. Sites and network update

P52 Pha Din GAW regional station and development orientation of climate change observing network in VietNam by Thi Quynh Hoa Vu

P53 Where is the missing CO2? A regional multi-species approach to trace the fate of atmospheric CO2 in Fiordland National Park, New Zealand by Peter Sperlich

P54 Atmospheric trace gas observations: Latest update from the Cape Point station by Casper Labuschagne

P55 High frequency measurements of atmospheric HFCs at a regional monitoring site in East Asia and the implications for regional emissions by Sunyoung Park

P56 GHG Vertical Profiles Measurement Program in the Amazon by Luciana Gatti

P57 Background Concentrations of CO2, CO and N2O in Brazilian Coast by Luciano Marani

P58 Study of long term SF6 mole fractions in Amazon and Brazilian Coast by Luana Basso

P59 Long Term CH4 measurements in Amazon and Brazilian Coast by Luana Basso

Session 10. Urban Observations and Networks

P60 Observed and simulated urban CO2 behavior around Jakarta megacity by Masahide Nishihashi

P61 MExico city's Regional Carbon Impacts (MERCI- CO2): combining high precision surface monitoring, with low-costs sensors, and total column measurements by Michel Ramonet

Session 11. Observations from the mobile platforms (aircraft, drone, balloon, etc)

P62 Characterising Methane Emissions using a Twin-Otter Airborne Platform by James France

P63 The Aircore system and campaign for vertical profile measurements of greenhouse gases in China by Miao Liang

P64 IAGOS-CORE and IAGOS-CARIBIC greenhouse gas observations from commercial airliners by Christoph Gerbig

P65 Pilot study of Unmanned Aerial Vehicles for sampling water vapor and water isotopes at high-latitudes provides implications for other trace gas sampling by Bruce Vaughn

25

Abstract submitted for GGMT-2019

Updates from the Wold Meteorological Organization

O. Tarasova

Atmospheric Environment Research Division, World Meteorological Organization

The eighteenth World Meteorological Congress (Cg-18, Geneva, 3–14 June 2019) adopted a historical reform of the WMO constituent bodies to embrace a more comprehensive Earth system approach, with a stronger focus on water resources and the ocean, more coordinated climate activities and a more concerted effort to translate science into services for society. The Congress approved a new WMO strategic plan 2020-2023 and new governance structure is aligned to it. The key elements of the new structure and their role will be explained in the presentation. The Scientific Steering Committee on Environmental Pollution and Atmospheric Chemistry (EPAC-SSC) started discussing the alignment of the GAW activities with the proposed structure at its meeting in November 2018. This proposal will be further elaborated at the SSC meeting in 2019 and the initial thinking will be presented to GGMT-2019 participants. The presentation will highlight the developments of the global greenhouse gas levels and the state of the global climate. The collaboration between WMO and the United Nations Framework Convention on Climate Change (UNFCCC) will be discuss including the joint activities related to the Integrated Global Greenhouse Gas Information System (IG3IS). The presentation will highlight activities of the IG3IS office as well as development of the initiative itself. The political drivers of the climate agenda will be articulated in the context of the recently published IPCC reports.

In 2019 the Global Atmosphere Watch Programme turned 30 years and the celebration activities will be highlighted. The progress of “science-for-services” concept will be demonstrated using the examples of the newly established core projects.

26


27


T1


Towards an International Reference Network for Greenhouse Gases Arlyn Andrews1, Ed Dlugokencky1, Kirk Thoning1, Colm Sweeney1, John Miller1, Kathryn McKain1,2, Gabrielle Pétron1,2, Andrew Crotwell1,2, Bradley Hall1, Benjamin Miller1,2, Steve Montzka1, James Elkins1, Pieter Tans1 1. NOAA GMD 2. CIRES

NOAA’s Global Greenhouse Gas Reference Network includes our cooperative global whole-air flask sampling network, in situ measurements from surface and tower sites, and measurements of flask air samples from aircraft. The major greenhouse gases, carbon dioxide, methane and nitrous oxide, are measured, along with a large suite of isotopes, halocarbons, hydrocarbons and other trace gases. The term “reference network” was chosen to emphasize the quality and traceability of the measurements as well as the long-term stability of the network. The WMO GGMT community has a long history of promoting these objectives, and the concept of an international reference network for greenhouse gases is timely, as new remote sensing approaches and networks of inexpensive sensors are rapidly emerging with a wide range of measurement objectives and quality. At NOAA, we are working to document measurement protocols, to quantify the uncertainties of our greenhouse gas measurements, and to identify and reduce systematic errors through laboratory tests and through cross-laboratory and intra-laboratory comparisons of standards and field measurements using a variety of measurement approaches. We will present examples of ongoing challenges and progress from NOAA’s network along with a proposal to develop certification criteria for reference network measurements.

28

T2


Labelling process in ICOS atmosphere and quality control steps towards the first official data releases Leonard Rivier1, Amara Abbaris1, Dylan Desbree1, Lynn Hazan1, Olivier Laurent1, Michel Ramonet1, Jerome Tarniewicz1, Carole Philippon1, Khalil Yala1, Camille Yver-Kwok1 1. LSCE/ICOS ATC

ICOS has made its second official atmospheric data release last summer, the largest GHG integrated data release in the world contributing to the global WMO GAW network. Prior to this release the ICOS atmosphere stations have gone through a 13 steps labelling process including, station geographical situation inspection, internal training, calibration procedure, data flagging tools and measurement optimisation. We will also describe the various QA/QC implemented so far in ICOS atmosphere including bias assessment, local contamination, drying system efficiency, leakage test, flask- In-situ comparison and a measurement uncertainty computed based on long and short term targets. Future ICOS Atmosphere development including new measured parameters will also be presented.

29

T2


Labelling process in ICOS atmosphere and quality control steps towards the first official data releases Leonard Rivier1, Amara Abbaris1, Dylan Desbree1, Lynn Hazan1, Olivier Laurent1, Michel Ramonet1, Jerome Tarniewicz1, Carole Philippon1, Khalil Yala1, Camille Yver-Kwok1 1. LSCE/ICOS ATC

ICOS has made its second official atmospheric data release last summer, the largest GHG integrated data release in the world contributing to the global WMO GAW network. Prior to this release the ICOS atmosphere stations have gone through a 13 steps labelling process including, station geographical situation inspection, internal training, calibration procedure, data flagging tools and measurement optimisation. We will also describe the various QA/QC implemented so far in ICOS atmosphere including bias assessment, local contamination, drying system efficiency, leakage test, flask- In-situ comparison and a measurement uncertainty computed based on long and short term targets. Future ICOS Atmosphere development including new measured parameters will also be presented.

T3


Can your network stand the test of time?

Colm Sweeney1, Kathryn Mckain1, Don Neff1, Arlyn Andrews1, Bianca Baier1

1. NOAA Boulder

From its inception, the NOAA Greenhouse Gas Reference Network Programmable Flask Package (PFP) has been a critical part of the both the Tall Tower and Aircraft Programs at NOAA’s Global Monitoring Division (GMD) Carbon Cycle Greenhouse Gases (CCGG) Group. These samples allow for more than 55 trace gas species to be collected in one sample, with each gas analyzed on the same calibrated instrument housed at either GMD or at the University Colorado, ensuring site-to-site comparability. Despite extensive initial tests of this sampling system, significant biases in carbon dioxide measurements have arisen over the last decade and a half that underscore the necessity to continue to find ways to challenge your sampling system and its ability to produce repeatable, compatible and comparable measurements. In this presentation we will show how water vapor and surface effects can induce both positive and negative biases in PFP measurements of CO2. We will also show how these findings are applicable to other whole-air sampling systems like the AirCore, which is used to sample more than 98% of the atmospheric column using a long (>60 m) stainless steel tube.

30

T4


Update on CO, CO, and N2O calibration scales

Brad Hall1, Andrew Crotwell2, Duane Kitzis2, Pieter Tans1, Thomas Mefford2, Gabrielle Petron2

1. NOAA 2. CIRES/NOAA

As a Central Calibration Laboratory, the NOAA Global Monitoring Division is tasked with maintaining and distributing scales for CO2, CH4, CO, N2O, and SF6. Maintaining scales involves on-going comparisons between and among primary, secondary, and tertiary standards, as well as working to improve scale accuracy, reproducibility of scale transfer, and stability. We will report on recent efforts to improve scales for CO2, CO, and N2O. For CO2, we have investigated a bias in the X2007 scale related to our manometric method used to determine the CO2 mole fractions of our primary standards, and will provide an update on a scale revision first proposed at GGMT-2017. We have pursued an independent method based on a gravimetric technique to verify/evaluate the proposed scale revision, and have also performed experiments to better understand uncertainties associated with our manometric method. For CO, we continue to use CH4 as an internal tracer to prepare independent standards 2-3 time per year, which are used to track drift in the primary standards that define the CO X2014A scale. For N2O, the current X2006A primary standards (in synthetic air without argon) are not suitable for direct calibration of optical analytical systems due to matrix effects. We are working on preparing primary standards in scrubbed whole air to allow direct calibration of optical systems.

31

T4


Update on CO, CO, and N2O calibration scales

Brad Hall1, Andrew Crotwell2, Duane Kitzis2, Pieter Tans1, Thomas Mefford2, Gabrielle Petron2

1. NOAA 2. CIRES/NOAA

As a Central Calibration Laboratory, the NOAA Global Monitoring Division is tasked with maintaining and distributing scales for CO2, CH4, CO, N2O, and SF6. Maintaining scales involves on-going comparisons between and among primary, secondary, and tertiary standards, as well as working to improve scale accuracy, reproducibility of scale transfer, and stability. We will report on recent efforts to improve scales for CO2, CO, and N2O. For CO2, we have investigated a bias in the X2007 scale related to our manometric method used to determine the CO2 mole fractions of our primary standards, and will provide an update on a scale revision first proposed at GGMT-2017. We have pursued an independent method based on a gravimetric technique to verify/evaluate the proposed scale revision, and have also performed experiments to better understand uncertainties associated with our manometric method. For CO, we continue to use CH4 as an internal tracer to prepare independent standards 2-3 time per year, which are used to track drift in the primary standards that define the CO X2014A scale. For N2O, the current X2006A primary standards (in synthetic air without argon) are not suitable for direct calibration of optical analytical systems due to matrix effects. We are working on preparing primary standards in scrubbed whole air to allow direct calibration of optical systems.

T5


Implementation of the WMO CO2 X2019 scale revision

Andrew Crotwell1,2, Bradley Hall1, Arlyn Andrews1, Edward Dlugokencky1, Duane Kitzis1,2, Thomas Mefford1,2, John Mund1,2, Pieter Tans1, Kirk Thoning1

1. Global Monitoring Division, Earth System Research laboratory, NOAA, Boulder CO 2. Cooperative Institute for Environmental Sciences, University of Colorado, Boulder CO

Advances in our understanding of the NOAA manometric system as well as a longer time series of measurements and an improved CO2 calibration system for propagating the scale have led to a better understanding of the primary standards that define the WMO CO2 scale. A revision to the WMO CO2 scale (WMO CO2 X2019) has been proposed to improve its accuracy. Implementation of the new scale involves a reassessment of primary to secondary and secondary to tertiary comparisons and will improve the internal consistency across both time and mole fraction range. The revised scale will be propagated to all NOAA CO2 calibrations to allow users to reprocess their data and improve consistency across monitoring networks. The scale propagation strategies used by NOAA on its calibration systems can be broken into four periods. 1) The current system using laser spectroscopic techniques, 2) the NDIR system calibrated with standards directly traceable to the current primary standards, 3) the NDIR system traceable to the current scale through standards whose original values were assigned by Scripps Institution of Oceanography, and 4) the period prior to ~1980 when the traceability of the measurements is not clearly defined. The more recent periods (periods 1 and 2) cover the time since NOAA assumed the role as CCL for CO2 and are of primary interest to the GGMT community. Generally, relative to WMO X2007, the revision scales with mole fraction (X2019 is approximately 0.004% greater than X2007). However, due to the non-linear response of the NDIR and the way in which the NDIR was calibrated, the implementation of X2019 on tertiary standards shows small but potentially significant deviations from the linear relationship. We report on the implementation of the X2019 scale revision to NOAA calibrations, the causes of the excursions from the linear relation between the two scales, and the implications of the revision for NOAA data.

32

T6


Towards an on-going comparison on the accuracy of standards and scales for atmospheric CO2 measurement

Robert Wielgosz1, Joele Viallon1, Philippe Moussay1, James Schmidt2, Christopher Meyer2, Fredrik Arrhen3, Stephen Maxwell2, Edgar Flores1, Faraz Idrees1, Tiphaine Choteau1

1. BIPM 2. NIST 3. RISE

Progress towards an on-going comparison of CO2 in air standards (BIPM.QM-K2), across the range (380 to 800) μmol/mol is described based on a manometric reference system maintained at the BIPM. It follows on from the successful completion of the CCQM-K120[1] (2019) and CCQM-P188[2] (2019) comparisons of CO2 in air standards at nominally (380, 480 and 800) μmol/mol, which compared 46 standards from National Metrology Institutes as well as the WMO’s Central Calibration Laboratory and the ICOS-CAL laboratory as well as the reference systems at the BIPM. These comparisons, carried out with comparative measurements at the BIPM, including bias corrections from differences in isotope ratios in standards, allowed reference values with standard uncertainties of 0.05 μmol/mol to be determined: a four-fold reduction compared to comparisons performed 10 years previously. The comparisons form part of a series, with future rounds planned for 2019 (N2O), 2022 (CO2) and 2023 (CH4), an activity that has allowed scale based and SI traceable approaches used in developing GHG gas standards to be compared and contrasted [3]. The advantages and required performance characteristics of using a primary manometric method for the comparisons are described, including: on-demand measurement; minimal gas use; short measurement time; low operating uncertainty (< 0.1 µmol/mol); and demonstrated stability. The reference system developed at the BIPM system is in Silconert-treated stainless-steel, providing much increased mechanical stability over glass systems, whilst reducing as much as possible adsorption/desorption of carbon dioxide on surfaces. Such effects have indeed been highlighted in recent publications, both inside gas cylinders and with o-rings used in glass manometer systems. Further validation studies are underway to reduce the measurement uncertainty of the system by better characterizing of the cryogenic extraction efficiency of CO2, adsorption effects, and the influence of residual water on measurements. The stability of the facility is being studied with two ensembles of nine CO2 in air mixtures, supplied by MPI-BGC Jena (over the range 380 µmol/ mol to 800 µmol/mol). Final validation of the facility is expected by 2021, which will be followed by the start of the BIPM.QM-K2 comparison service.

References

[1] Flores E. et al., CCQM-K120 (Carbon dioxide at background and urban level), Metrologia, 2019, 56, Tech. Suppl., 08001

33

T6


Towards an on-going comparison on the accuracy of standards and scales for atmospheric CO2 measurement

Robert Wielgosz1, Joele Viallon1, Philippe Moussay1, James Schmidt2, Christopher Meyer2, Fredrik Arrhen3, Stephen Maxwell2, Edgar Flores1, Faraz Idrees1, Tiphaine Choteau1

1. BIPM 2. NIST 3. RISE

Progress towards an on-going comparison of CO2 in air standards (BIPM.QM-K2), across the range (380 to 800) μmol/mol is described based on a manometric reference system maintained at the BIPM. It follows on from the successful completion of the CCQM-K120[1] (2019) and CCQM-P188[2] (2019) comparisons of CO2 in air standards at nominally (380, 480 and 800) μmol/mol, which compared 46 standards from National Metrology Institutes as well as the WMO’s Central Calibration Laboratory and the ICOS-CAL laboratory as well as the reference systems at the BIPM. These comparisons, carried out with comparative measurements at the BIPM, including bias corrections from differences in isotope ratios in standards, allowed reference values with standard uncertainties of 0.05 μmol/mol to be determined: a four-fold reduction compared to comparisons performed 10 years previously. The comparisons form part of a series, with future rounds planned for 2019 (N2O), 2022 (CO2) and 2023 (CH4), an activity that has allowed scale based and SI traceable approaches used in developing GHG gas standards to be compared and contrasted [3]. The advantages and required performance characteristics of using a primary manometric method for the comparisons are described, including: on-demand measurement; minimal gas use; short measurement time; low operating uncertainty (< 0.1 µmol/mol); and demonstrated stability. The reference system developed at the BIPM system is in Silconert-treated stainless-steel, providing much increased mechanical stability over glass systems, whilst reducing as much as possible adsorption/desorption of carbon dioxide on surfaces. Such effects have indeed been highlighted in recent publications, both inside gas cylinders and with o-rings used in glass manometer systems. Further validation studies are underway to reduce the measurement uncertainty of the system by better characterizing of the cryogenic extraction efficiency of CO2, adsorption effects, and the influence of residual water on measurements. The stability of the facility is being studied with two ensembles of nine CO2 in air mixtures, supplied by MPI-BGC Jena (over the range 380 µmol/ mol to 800 µmol/mol). Final validation of the facility is expected by 2021, which will be followed by the start of the BIPM.QM-K2 comparison service.

References

[1] Flores E. et al., CCQM-K120 (Carbon dioxide at background and urban level), Metrologia, 2019, 56, Tech. Suppl., 08001

T6


[2] Report of the pilot study CCQM-P188: Carbon dioxide in air (380 to 800) µmol/mol, Flores E., Viallon J., Choteau T., Moussay P., Idrees F., Wielgosz R.I., Meyer C., Rzesanke D., Metrologia, 2019, 56, Tech. Supp., 08012

[3] Brewer P.J., Brown R.J.C., Tarasova O.A., Hall B., Rhoderick G.C., Wielgosz R.I., SI traceability and scales for underpinning atmospheric monitoring of greenhouse gases, Metrologia, 2018, 55(5), S174-S181

34

T7


Training, twinning, and capacity building in support of greenhouse gas observations in data sparse regions

Martin Steinbacher1, Christoph Zellweger2, Lukas Emmenegger1, Brigitte Buchmann2

1. Empa, Laboratory for Air Pollution / Environmental Technology, Duebendorf, Switzerland 2. Empa, Department Mobility, Energy and Environment, Duebendorf, Switzerland

Despite the ongoing considerable improvement in spatial data coverage and the large number of GAW stations around the globe, the availability of long-term, consistent, and publicly accessible greenhouse gases observations of adequate quality is still sparse particularly in tropical regions and developing countries. The GAW Quality Assurance/Scientific Activity Centre (QA/SAC Switzerland), closely linked to the World Calibration Centre also hosted by Empa (WCC-Empa), supports GAW stations in data sparse regions to start, resume and maintain such observations sustainably. To do so, QA/SAC Switzerland focusses on training, twinning, and capacity building, i.e. provides technical support of GAW stations, advice for adequate instrument selection, instrument operation and calibration strategies, and it assists in data quality and data submission issues. This presentation highlights experiences and lessons-learnt from support and teaching activities at the GAW Training and Education Centre (GAWTEC), other training sessions, one-to-one trainings, and during maintenance visits and station audits. Our experience shows that – when starting with basic infrastructure and willingness to perform high-precision trace gas observations in a remote environment – it typically takes a decade to reach the status of a fully autonomous monitoring station with high-quality data, and good visibility within GAW and the scientific community. Our presentation critically assesses the available documentation, identifies shortcomings, and suggests the preparation of straightforward checklists and guidelines dedicated for unexperienced users and novices.

35

T7


Training, twinning, and capacity building in support of greenhouse gas observations in data sparse regions

Martin Steinbacher1, Christoph Zellweger2, Lukas Emmenegger1, Brigitte Buchmann2

1. Empa, Laboratory for Air Pollution / Environmental Technology, Duebendorf, Switzerland 2. Empa, Department Mobility, Energy and Environment, Duebendorf, Switzerland

Despite the ongoing considerable improvement in spatial data coverage and the large number of GAW stations around the globe, the availability of long-term, consistent, and publicly accessible greenhouse gases observations of adequate quality is still sparse particularly in tropical regions and developing countries. The GAW Quality Assurance/Scientific Activity Centre (QA/SAC Switzerland), closely linked to the World Calibration Centre also hosted by Empa (WCC-Empa), supports GAW stations in data sparse regions to start, resume and maintain such observations sustainably. To do so, QA/SAC Switzerland focusses on training, twinning, and capacity building, i.e. provides technical support of GAW stations, advice for adequate instrument selection, instrument operation and calibration strategies, and it assists in data quality and data submission issues. This presentation highlights experiences and lessons-learnt from support and teaching activities at the GAW Training and Education Centre (GAWTEC), other training sessions, one-to-one trainings, and during maintenance visits and station audits. Our experience shows that – when starting with basic infrastructure and willingness to perform high-precision trace gas observations in a remote environment – it typically takes a decade to reach the status of a fully autonomous monitoring station with high-quality data, and good visibility within GAW and the scientific community. Our presentation critically assesses the available documentation, identifies shortcomings, and suggests the preparation of straightforward checklists and guidelines dedicated for unexperienced users and novices.

T8


Recent Activities and Achievements of WCC-Empa

Christoph Zellweger1, Martin Steinbacher1, Rainer Steinbrecher2, Lukas Emmenegger1, Brigitte Buchmann3

1. Empa, Laboratory for Air Pollution / Environmental Technology, Duebendorf, Switzerland 2. Karlsruhe Institute of Technology (KIT), Institute of Meteorology and Climate Research (IMK-IFU), Garmisch-Partenkirchen, Germany 3. Empa, Department Mobility, Energy and Environment, Duebendorf, Switzerland

Empa operates the World Calibration Centre for Carbon Monoxide (CO), Methane (CH4), Carbon Dioxide (CO2) and Surface Ozone (WCC-Empa) since 1996 as a Swiss contribution to the Global Atmosphere Watch (GAW) programme and has conducted over 90 system- and performance audits. Since 2009, WCC-Empa collaborates with the World Calibration Centre for Nitrous Oxide (WCC-N2O) hosted by the Karlsruhe Institute of Technology (KIT), Institute of Meteorology and Climate Research (IMK-IFU) to increase the number of N2O audits at GAW stations. WCC-Empa is responsible for verifying the traceability of the measurements to the designated GAW reference maintained by Central Calibration Laboratories. The activities of WCC-Empa are a key element to sustain and improve the data quality required for climate and environmental research. This presentation gives an update on results and achievements of system- and performance audits at GAW stations. The focus will be on CO measurements, since there was significant instrumental development during the past decade. This leads to improved accuracy of CO measurements, but interferences may jeopardize the capability of the new methods if they are not adequately compensated. For example, cavity ring down spectroscopy in the near infrared (NIR-CRDS) often suffers from water vapor interference leading to a bias of up to several percent, which can be difficult to compensate [1]. We will show this based on a number of recently acquired and tested NIR-CRDS instruments. On the other hand, NIR-CRDS also facilitates new calibration strategies due to the wide linear range. We will further present our new calibration method for CO, which should better account for CO growth in standard gases.

Reference

[1] Zellweger, C., Steinbrecher, R., Laurent, O., Lee, H., Kim, S., Emmenegger, L., Steinbacher, M., and Buchmann, B.: Recent advances in measurement techniques for atmospheric carbon monoxide and nitrous oxide observations, Atmos. Meas. Tech. Discuss., 2019, 1-28, 2019.

36

T9


Comparison of in situ measurements of CO2 and CH4 at the Cape Grim Baseline Station

Zoe Loh1, Paul Krummel1, Darren Spencer1, Ray Langenfelds1, L. Paul Steele1, Paul Fraser1, Blagoj Mitrevski1, Elise Guerette1, Jeremy Ward2, Nigel Somerville2, Sam Cleland2

1. Climate Science Centre, CSIRO Oceans & Atmosphere 2. Cape Grim Baseline Air Pollution Station, Australian Bureau of Meteorology

In situ measurements of atmospheric CO2 and CH4 have been made at Cape Grim Baseline Air Pollution Station, in northwest Tasmania since 1976 and 1984, respectively. The instruments providing CO2 measurements have been upgraded and replaced several times over the past 40 years, with a LoFlo Mk2 high precision non-dispersive infrared (NDIR) instrument functioning as our workhorse since 2004. Methane measurements have been made with a gas chromatography-flame ionisation detector method, a component of a gas chromatograph multi-detector (GC-MD) system (one ambient aliquot every 40 minutes) operated as part of the Advanced Global Atmospheric Gases Experiment (AGAGE) since 1993. In mid-2012, a cavity ring-down spectrometer (CRDS) instrument (Picarro Inc., model G2301), measuring both CO2 and CH4 (as well as H2O), was installed at Cape Grim, for trial ahead of retirement of the LoFlo instrument (still operational at the time of writing), and to significantly improve the temporal coverage of our CH4 record. In January 2017, a second Picarro G2301 CRDS instrument was installed at Cape Grim to provide redundancy for these key measurements. The technical details of gas handling and calibration are quite different for each type of measurement. For instance, the LoFlo instrument uses chemical drying (anhydrous magnesium perchlorate; Mg(ClO4)2) plus a Nafion membrane to measure dry air, whereas the Picarro instruments measure untreated ambient air (including its water content) and we make an empirical correction to obtain dry air mole fractions. This presentation will provide a detailed comparison between pairs of in situ records for each trace gas, examining how effective our gas handling and calibration regimes are at attaining and sustaining the desired WMO compatibility goals of ±2 ppb CH4 and ±0.05 ppm CO2, at this Southern Hemisphere site.

37

T9


Comparison of in situ measurements of CO2 and CH4 at the Cape Grim Baseline Station

Zoe Loh1, Paul Krummel1, Darren Spencer1, Ray Langenfelds1, L. Paul Steele1, Paul Fraser1, Blagoj Mitrevski1, Elise Guerette1, Jeremy Ward2, Nigel Somerville2, Sam Cleland2

1. Climate Science Centre, CSIRO Oceans & Atmosphere 2. Cape Grim Baseline Air Pollution Station, Australian Bureau of Meteorology

In situ measurements of atmospheric CO2 and CH4 have been made at Cape Grim Baseline Air Pollution Station, in northwest Tasmania since 1976 and 1984, respectively. The instruments providing CO2 measurements have been upgraded and replaced several times over the past 40 years, with a LoFlo Mk2 high precision non-dispersive infrared (NDIR) instrument functioning as our workhorse since 2004. Methane measurements have been made with a gas chromatography-flame ionisation detector method, a component of a gas chromatograph multi-detector (GC-MD) system (one ambient aliquot every 40 minutes) operated as part of the Advanced Global Atmospheric Gases Experiment (AGAGE) since 1993. In mid-2012, a cavity ring-down spectrometer (CRDS) instrument (Picarro Inc., model G2301), measuring both CO2 and CH4 (as well as H2O), was installed at Cape Grim, for trial ahead of retirement of the LoFlo instrument (still operational at the time of writing), and to significantly improve the temporal coverage of our CH4 record. In January 2017, a second Picarro G2301 CRDS instrument was installed at Cape Grim to provide redundancy for these key measurements. The technical details of gas handling and calibration are quite different for each type of measurement. For instance, the LoFlo instrument uses chemical drying (anhydrous magnesium perchlorate; Mg(ClO4)2) plus a Nafion membrane to measure dry air, whereas the Picarro instruments measure untreated ambient air (including its water content) and we make an empirical correction to obtain dry air mole fractions. This presentation will provide a detailed comparison between pairs of in situ records for each trace gas, examining how effective our gas handling and calibration regimes are at attaining and sustaining the desired WMO compatibility goals of ±2 ppb CH4 and ±0.05 ppm CO2, at this Southern Hemisphere site.

T10


Comparisons of non-CO2 trace gas measurements between AGAGE and NOAA at common sites Paul Krummel1, Steve Montzka2, Chris Harth3, Ben Miller2, Jens Muhle3, Ed Dlugokencky2, Peter Salameh3, Brad Hall2, Simon O'Doherty4, Geoff Dutton2, Dickon Young4, David Nance2, Ray Langenfelds1, Jim Elkins2, Zoe Loh1, Chris Lunder5, Paul Fraser1, Ove Hermansen5, Paul Steele1, Nada Derek1, Blagoj Mitrevski1, Ray Weiss3, Ron Prinn6 1. Climate Science Centre, CSIRO Oceans & Atmosphere, Aspendale, Victoria, Australia 2. NOAA Earth System Research Laboratory (ESRL), Boulder, Colorado, USA 3. Scripps Institution of Oceanography (SIO), University of California San Diego, La Jolla, California, USA 4. School of Chemistry, University of Bristol, Bristol, United Kingdom 5. Norwegian Institute for Air Research (NILU), Kjeller, Norway 6. Center for Global Change Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA

Three-dimensional atmospheric model studies that estimate global and regional emissions of greenhouse and ozone depleting gases often require data from more than one network’s group of stations. A prime example of this is the recent CFC-11 paper by Rigby et al. [1] that utilised data from both the NOAA and AGAGE networks to identify the source region responsible for the global increase in this banned chemical. It is therefore important to be able to accurately merge atmospheric trace gas data sets from different laboratories and networks, which may use different calibration scales and different measurement techniques. To facilitate this, on-going comparisons of in situ data with independent flask and/or in situ data collected at common sites are useful as they are sensitive diagnostic tests of data quality for the laboratories involved, and they provide a basis for merging these data sets with confidence. For the past 15+ years comparisons (now more than 400 individual comparisons) of non-CO2 greenhouse gases (now totalling more than 45 species) have been carried out twice yearly and presented at meetings of Advanced Global Atmospheric Gases Experiment (AGAGE) scientists and Cooperating Networks. The majority of these comparisons are between AGAGE in situ (primarily using SIO calibration scales) and NOAA flask data from the Halocarbons and other Atmospheric Trace Species (HATS) and Carbon Cycle Greenhouse Gas (CCGG) groups at NOAA/ESRL. The six common measurement sites are: Cape Grim, Australia; Cape Matatula, American Samoa (includes some NOAA in situ data); Ragged Point, Barbados; Trinidad Head, USA; Mace Head, Ireland; and Zeppelin, Norway. This presentation will give an update of the comparisons presented at previous GGMT meetings summarising the methodology and resultant output, with detailed results from selected comparisons and new comparisons that have been performed. While the presentation will focus primarily on the major greenhouse gases, a summary of the overall level of agreement, the so called ‘scale conversion factors’, between AGAGE and NOAA data/scales based on the comparisons from the field sites for a range of species will also be given.

Reference

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[1] Rigby et al., An increase in CFC-11 emissions from China inferred from atmospheric observations, Nature, 596, 546-550, https://doi.org/10.1038/s41586-019-1193-4, 2019.

39

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[1] Rigby et al., An increase in CFC-11 emissions from China inferred from atmospheric observations, Nature, 596, 546-550, https://doi.org/10.1038/s41586-019-1193-4, 2019.

T11


Standard of greenhouse gases measurement

Jeongsoon Lee1, Jeongsik Lim1, Gahae Kim1, Jinbok Lee1

1. KRISS

To monitor and evaluate greenhouse gases quantitatively it is essential to have a well defined reference mterial, which is directly related with determination of measurement uncertainties. Through reference as a chain of calibrations, metrological traceability is kept unbroken. Recently both an amount of substance and their mixture composition have been needed to observe greenhouse gases in the atmosphere since various optic instrument were developed and applied to the measurement stations. Hence in this work, a standard mixture was developed whose not only an amount of main substance but also its composition of balance materials were assigned. As a result, it is strongly expected to enhance measurement comparability among observation stations by being used for calibrating various kinds of optic instrument.

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T12


Breakthrough in Negating the Impact of Adsorption in Gas Reference Materials

Paul Brewer1, Richard Brown1, Eric Mussell Webber1, Sivan van Aswegan1, Michael Ward1, Ruth Hill-Pearce1, Dave Worton1

1. National Physical Laboratory

We present a novel exchange dilution method for preparing gas reference materials used for underpinning measurements of amount-of-substance fraction of greenhouse gases for atmospheric observations. Gas mixtures are diluted in the same cylinder by releasing an aliquot of the parent mixture before adding the matrix gas. This differs to conventional methods where dilutions are achieved by transferring the parent mixture to another cylinder used to store the reference material. The benefit of this approach is that losses due to adsorption to the walls of the cylinder and the valve are reduced as the parent mixture pacifies the surface with only a negligible relative change in amount-of-substance fraction. This development has significant implications for improving the accuracy of gas reference materials beyond the current state of the art. It is particularly relevant to carbon dioxide, as understanding the adsorption effects is the major obstacle to advancing the measurement science. The method also has the potential to remove the reliance on proprietary cylinder surface pre-treatments.

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Breakthrough in Negating the Impact of Adsorption in Gas Reference Materials

Paul Brewer1, Richard Brown1, Eric Mussell Webber1, Sivan van Aswegan1, Michael Ward1, Ruth Hill-Pearce1, Dave Worton1

1. National Physical Laboratory

We present a novel exchange dilution method for preparing gas reference materials used for underpinning measurements of amount-of-substance fraction of greenhouse gases for atmospheric observations. Gas mixtures are diluted in the same cylinder by releasing an aliquot of the parent mixture before adding the matrix gas. This differs to conventional methods where dilutions are achieved by transferring the parent mixture to another cylinder used to store the reference material. The benefit of this approach is that losses due to adsorption to the walls of the cylinder and the valve are reduced as the parent mixture pacifies the surface with only a negligible relative change in amount-of-substance fraction. This development has significant implications for improving the accuracy of gas reference materials beyond the current state of the art. It is particularly relevant to carbon dioxide, as understanding the adsorption effects is the major obstacle to advancing the measurement science. The method also has the potential to remove the reliance on proprietary cylinder surface pre-treatments.

T13


Potential Bias in Preliminary Estimates of Global LLGHG Trends

Edward Dlugokencky1, Kirk Thoning1, Molly Crotwell1

1. NOAA GMD

NOAA’s greenhouse gas trend web pages are very popular, receiving tens of thousands of hits per month. On these pages, users can currently find recent global trends for CO2 and CH4 based on weekly air samples collected as part of our cooperative global air sampling network, each updated monthly. There has been particular interest in the estimates of CO2 and CH4 global annual means and annual increase at the start of each new year, despite their susceptibility to potential bias. When the first estimates of annual means and annual increases for the previous year are reported in March, the calculation is limited by available data from our air sampling network. In early-March, because many air sampling sites are remote, many samples from the previous year have not yet been received and analyzed. This is especially important for calculating the annual increase. We’ve looked in detail at potential sources of bias in these preliminary estimates. As an example, compared to successive months of refinement, our initial estimate of CH4 annual increase can be in error by up to ~ ±3 ppb/yr, which is significant given that CH4 has had an average increase of 7.2 ppb/yr over the past 10 years. In this presentation, we will explore potential contributors to errors in preliminary globally averaged monthly means, annual means, and annual increases for key LLGHGs.

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T14


Taking in-situ greenhouse gas information into the big data era

Alex Vermeulen1, Lynn Hazan2, Margareta Hellström3, Ute Karstens3, Oleg Mirzov3, Michel Ramonet2, Leonard Rivier2, Werner Kutsch1

1. ICOS ERIC-Carbon Portal 2. ICOS ATC@LSCE 3. ICOS CP@Lund University

Adaptation and mitigation of climate change has increased the interest and economic value of information on the atmospheric composition regarding greenhouse gases. There are also many other drivers that put pressure on the way we produce, process and publish the greenhouse gas information, including the demand for transparency and reproducibility. Without compromising on the quality of the data there is a strong need for quicker and completely open data sharing that at the same time allows for machine to machine data sharing. Next to these pressures, there is in Europe also support from the H2020 framework program to provide data according the so-called FAIR principles (Wilkinson et al, 2017). In this program ICOS is involved in the ENVRIFAIR project to work on implementing the FAIR principles in the European environmental research infrastructures, further improving on the already basically FAIR ICOS data concept by focusing on enhancing interoperability and re-use of the data. In this presentation we would like to present some elements of the way forward to guide a discussion on the way forward regarding the data publishing by our communities, also considering existing initiatives and developing (global) standards like the WMO WIGOS and WIS. The ICOS approach, that deploys a semantic web and linked open data approach on top of more traditional and legacy (proven) technology, is certainly not the only way to reach the required level of FAIRness, but it does serve as an example on how to provide the glue between different community standards and how to connect to other (global) catalogs of data and services. Central to the ICOS approach is to make sure that the data usage is tracked as well as is possible with open and free data, and that the data is correctly cited and acknowledged. Supporting this in the workflow of the scientific process requires the use of persistent identifiers for data objects, data providers and institutes, and the cooperation of both the users and the citation data providers.

43

T14


Taking in-situ greenhouse gas information into the big data era

Alex Vermeulen1, Lynn Hazan2, Margareta Hellström3, Ute Karstens3, Oleg Mirzov3, Michel Ramonet2, Leonard Rivier2, Werner Kutsch1

1. ICOS ERIC-Carbon Portal 2. ICOS ATC@LSCE 3. ICOS CP@Lund University

Adaptation and mitigation of climate change has increased the interest and economic value of information on the atmospheric composition regarding greenhouse gases. There are also many other drivers that put pressure on the way we produce, process and publish the greenhouse gas information, including the demand for transparency and reproducibility. Without compromising on the quality of the data there is a strong need for quicker and completely open data sharing that at the same time allows for machine to machine data sharing. Next to these pressures, there is in Europe also support from the H2020 framework program to provide data according the so-called FAIR principles (Wilkinson et al, 2017). In this program ICOS is involved in the ENVRIFAIR project to work on implementing the FAIR principles in the European environmental research infrastructures, further improving on the already basically FAIR ICOS data concept by focusing on enhancing interoperability and re-use of the data. In this presentation we would like to present some elements of the way forward to guide a discussion on the way forward regarding the data publishing by our communities, also considering existing initiatives and developing (global) standards like the WMO WIGOS and WIS. The ICOS approach, that deploys a semantic web and linked open data approach on top of more traditional and legacy (proven) technology, is certainly not the only way to reach the required level of FAIRness, but it does serve as an example on how to provide the glue between different community standards and how to connect to other (global) catalogs of data and services. Central to the ICOS approach is to make sure that the data usage is tracked as well as is possible with open and free data, and that the data is correctly cited and acknowledged. Supporting this in the workflow of the scientific process requires the use of persistent identifiers for data objects, data providers and institutes, and the cooperation of both the users and the citation data providers.

T15


ObsPack 5 Years Later: Where Are We Now and Where Are We Going? Kenneth Schuldt1, Ingrid van der Laan-Luijkx2, John Mund1, Pieter Tans3, Arlyn Andrews3, ObsPack data providers4 1. Cooperative Institute for Research in Environmental Sciences (CIRES) 2. Wageningen University 3. NOAA Earth System Research Laboratory, Global Monitoring Division (GMD) 4. Various

The Observation Package (ObsPack) framework is a data packaging tool designed to bring together atmospheric greenhouse gas observations from a variety of sampling platforms and data providers, prepare them with specific applications in mind, and package and distribute them in a self-consistent and well-documented product. We deliver multiple products in ObsPack format for carbon dioxide (CO2), methane (CH4), and sulfur hexafluoride (SF6) with plans for products for more gas species coming soon. ObsPack has seen growing popularity across various fields among researchers, students, and teachers. More datasets are included with each release and we are always looking to expand what is available. I also cover our plans regarding the new X2019 CO2 scale.

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The evolution of AGAGE: Overview of improved measurement technologies for the quantification of GHG and ODS emissions Ray Weiss1, Jens Mühle1, Christina Harth1, Peter Salameh1, Roland Schmidt1, Martin Vollmer2, Tim Arnold3, Dickon Young4, Jooil Kim1, Blagoj Mitrevski5, Brian Lerner6, Doug Worsnop6, Simon O'Doherty4, Paul Krummel5, Peter Simmonds4, Paul Fraser5, Ron Prinn7 1. Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, USA 2. Laboratory for Air Pollution and Environmental Technology, Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Switzerland 3. National Physical Laboratory, Teddington, Middlesex, and School of GeoSciences, University of Edinburgh, Edinburgh, United Kingdom 4. School of Chemistry, University of Bristol, Bristol, United Kingdom 5. Climate Science Centre, CSIRO Oceans and Atmosphere, Aspendale, Victoria, Australia 6. Aerodyne Research, Inc., Billerica, Massachusetts, USA 7. Center for Global Change Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA

Over the past three decades the Advanced Global Atmospheric Gases Experiment (AGAGE) automated high-frequency measurement program has evolved from the measurement of eight greenhouse gases (GHGs) and stratospheric ozone depleting substances (ODSs) at five remote stations, to the measurement of more than 50 such gases at eleven remote and semi-remote stations and at six central laboratories. In the process, the technology for these measurements and their calibration and data processing has also evolved to keep pace with new technology, increased amounts of data, and with the changes in anthropogenic and natural GHG and ODS emissions. The focus of the program has also expanded from understanding global emissions, abundances and lifetimes of these gases to include the quantification of regional emissions and their changes in the context of environmental policy. An overview of some of these technological changes will be presented, including: the adaptation of the AGAGE Medusa automated gas chromatograph/mass spectrometer (GC/MS) instrument system to Stirling cooling technology; the addition of newly introduced industrial compounds to the suite of Medusa measurements; the expansion of AGAGE into cavity ring-down spectrometry (CRDS) measurements for the more-abundant gases; and initiatives to commercialize the Medusa technology and extend its capabilities from quadrupole MS detection to time-of-flight mass spectrometric (ToFMS) detection. The environmental policy imperatives for these developments will also be addressed.

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The evolution of AGAGE: Overview of improved measurement technologies for the quantification of GHG and ODS emissions Ray Weiss1, Jens Mühle1, Christina Harth1, Peter Salameh1, Roland Schmidt1, Martin Vollmer2, Tim Arnold3, Dickon Young4, Jooil Kim1, Blagoj Mitrevski5, Brian Lerner6, Doug Worsnop6, Simon O'Doherty4, Paul Krummel5, Peter Simmonds4, Paul Fraser5, Ron Prinn7 1. Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, USA 2. Laboratory for Air Pollution and Environmental Technology, Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Switzerland 3. National Physical Laboratory, Teddington, Middlesex, and School of GeoSciences, University of Edinburgh, Edinburgh, United Kingdom 4. School of Chemistry, University of Bristol, Bristol, United Kingdom 5. Climate Science Centre, CSIRO Oceans and Atmosphere, Aspendale, Victoria, Australia 6. Aerodyne Research, Inc., Billerica, Massachusetts, USA 7. Center for Global Change Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA

Over the past three decades the Advanced Global Atmospheric Gases Experiment (AGAGE) automated high-frequency measurement program has evolved from the measurement of eight greenhouse gases (GHGs) and stratospheric ozone depleting substances (ODSs) at five remote stations, to the measurement of more than 50 such gases at eleven remote and semi-remote stations and at six central laboratories. In the process, the technology for these measurements and their calibration and data processing has also evolved to keep pace with new technology, increased amounts of data, and with the changes in anthropogenic and natural GHG and ODS emissions. The focus of the program has also expanded from understanding global emissions, abundances and lifetimes of these gases to include the quantification of regional emissions and their changes in the context of environmental policy. An overview of some of these technological changes will be presented, including: the adaptation of the AGAGE Medusa automated gas chromatograph/mass spectrometer (GC/MS) instrument system to Stirling cooling technology; the addition of newly introduced industrial compounds to the suite of Medusa measurements; the expansion of AGAGE into cavity ring-down spectrometry (CRDS) measurements for the more-abundant gases; and initiatives to commercialize the Medusa technology and extend its capabilities from quadrupole MS detection to time-of-flight mass spectrometric (ToFMS) detection. The environmental policy imperatives for these developments will also be addressed.

T17


A Detachable Trap Preconcentrator with a Gas Chromatograph-Mass Spectrometer for the Analysis of Trace Halogenated Greenhouse Gases

Doohyun Yoon1, Jeongsoon Lee1, Jeong Sik Lim1

1. Korea Research Institute of Standards and Science

A detachable trap preconcentrator coupled with a gas chromatograph-mass spectrometer (GC-MS) was developed for measuring trace amounts of anthropogenic halogenated greenhouse gases such as hydrofluorocarbons (HFCs) and nitrogen trifluoride (NF3). Hayesep D cooled to -135°C was used as an adsorbent for preconcentrating the target analytes. A differential trapping method was applied to remove major interfering substances such as CO2, N2, and O2 in order to ensure sufficient sampling volume of secondary injection trap. This was accomplished without using any CO2-removal agent such as molecular sieve adsorbents. Consequently, the temperature of the primary transfer trap was set to −75°C for selective desorption of a significant amount of CO2 that could be vented out. Meantime, the major components of air, e.g., N2 and O2, were vented out before transferring the analytes to the secondary injection trap, in order to protect the gas plumbing from pressure shock induced by rapid temperature ramping over 100°C/min in the secondary trap. When the traps were heated, linear motion was operated to detach them from the copper baseplate on the freezer, thereby restricting heat transfer to the freezer and maintaining the freezer close to the background temperature of −135°C. This trap design is a key improvement to address the insufficient cooling capacity of the employed freezer, allowing sensitive detection of trace halogenated greenhouse gases in GC-MS. NF3 and various HFCs at ambient levels were quantitatively and qualitatively measured with a precision of 0.35% at rates below 45 min/cycle. In particular, the limit of detection for NF3 was evaluated to be 0.2 pmol/mol, with linear responses at ambient concentration.

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Methane Source Localisation and Emission Quantification at Facility Scale Using Multi-beam Open Path Laser Dispersion Spectroscopy Mohammed Belal1, Arun Kannath1, Johnny Chu1, Neil Macleod2, Damien Weidmann2, Bill Hirst3, David Randell3 1. MIRICO Ltd, Unit 6 Zephyr Building, Didcot, Oxfordshire, OX11 0RL, UK 2. Space Science & Technology Dept., Rutherford Appleton Laboratory, Didcot, Oxfordshire, OX11 0QX, UK 3. Shell Global Solutions International B.V., Grasweg 31, 1031 HW Amsterdam, The Netherlands

Over 20 years, the global warming potential of methane is 86 times that of carbon dioxide but methane is short-lived in the atmosphere (~12 years) compared to the century plus lifetime of carbon dioxide. Therefore, quantifying methane emissions from a variety of activities (landfill, oil and gas operations, agriculture) supports legislative and mitigation activities for much more effective and rapid routes towards reducing climate forcing. Such mitigation requires locating and quantifying methane emission sources and measuring the efficacy of reduction measures. We present the development and field demonstration of a monitoring system fulfilling the above-mentioned needs. The instrument technology provides long-range multi beam open path concentration analysis, using mid-infrared laser light. The sensor is based on Laser Dispersion Spectroscopy (LDS): a new approach to tuneable laser spectroscopy delivering unique benefits for long open-path molecular sensing. Contrary to optical absorption techniques, LDS derives concentrations from the variation in refractive index induced by molecular resonance. The instrument effectively measures phase variations of light, which yields unique open-path sensing benefits: a) strong immunity to light intensity fluctuations, b) large and linear measurement dynamic range, and c) improved molecular selectivity. These instrument-level benefits deliver key advantages for long open path sensing in turbid and particulate-loaded atmospheres (e.g. rain, fog, snow…) and detecting dispersing gas, including complex molecular mixtures. The sensor offers continuous remote operation to quantify methane and providing spatial distribution of emission over large areas, supporting statistically validated emission data. The LDS sensor was evaluated in field tests using an extensive series of calibrated test releases of methane. The instrument is coupled to an array of 7 retroreflectors providing a fan of beams of different lengths. Each open-path beam is sequentially measured over ~0.1 second using an angular stepper motor mounted mirror. The precision of methane concentration measurements was found to be ~20 ppb in 100 ms over a ~100 m single open path. Applying an inverse solver method to the multiple open path-integrated temporal records of methane concentration and associated wind velocity data, we were able to recover the source emission rates and locations for 4 separate source patterns over the ~120m x 120m test area. Our Bayesian retrieval uses a Gaussian plume eddy dispersion model and Markov chain Monte Carlo approach to recover the source map solution and uncertainty bounds for all results. Accurate mapping and quantification of methane sources down to 1.2 kg/h was successfully demonstrated, even for sources outside the open path fan. A subsequent demonstration using a

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Methane Source Localisation and Emission Quantification at Facility Scale Using Multi-beam Open Path Laser Dispersion Spectroscopy Mohammed Belal1, Arun Kannath1, Johnny Chu1, Neil Macleod2, Damien Weidmann2, Bill Hirst3, David Randell3 1. MIRICO Ltd, Unit 6 Zephyr Building, Didcot, Oxfordshire, OX11 0RL, UK 2. Space Science & Technology Dept., Rutherford Appleton Laboratory, Didcot, Oxfordshire, OX11 0QX, UK 3. Shell Global Solutions International B.V., Grasweg 31, 1031 HW Amsterdam, The Netherlands

Over 20 years, the global warming potential of methane is 86 times that of carbon dioxide but methane is short-lived in the atmosphere (~12 years) compared to the century plus lifetime of carbon dioxide. Therefore, quantifying methane emissions from a variety of activities (landfill, oil and gas operations, agriculture) supports legislative and mitigation activities for much more effective and rapid routes towards reducing climate forcing. Such mitigation requires locating and quantifying methane emission sources and measuring the efficacy of reduction measures. We present the development and field demonstration of a monitoring system fulfilling the above-mentioned needs. The instrument technology provides long-range multi beam open path concentration analysis, using mid-infrared laser light. The sensor is based on Laser Dispersion Spectroscopy (LDS): a new approach to tuneable laser spectroscopy delivering unique benefits for long open-path molecular sensing. Contrary to optical absorption techniques, LDS derives concentrations from the variation in refractive index induced by molecular resonance. The instrument effectively measures phase variations of light, which yields unique open-path sensing benefits: a) strong immunity to light intensity fluctuations, b) large and linear measurement dynamic range, and c) improved molecular selectivity. These instrument-level benefits deliver key advantages for long open path sensing in turbid and particulate-loaded atmospheres (e.g. rain, fog, snow…) and detecting dispersing gas, including complex molecular mixtures. The sensor offers continuous remote operation to quantify methane and providing spatial distribution of emission over large areas, supporting statistically validated emission data. The LDS sensor was evaluated in field tests using an extensive series of calibrated test releases of methane. The instrument is coupled to an array of 7 retroreflectors providing a fan of beams of different lengths. Each open-path beam is sequentially measured over ~0.1 second using an angular stepper motor mounted mirror. The precision of methane concentration measurements was found to be ~20 ppb in 100 ms over a ~100 m single open path. Applying an inverse solver method to the multiple open path-integrated temporal records of methane concentration and associated wind velocity data, we were able to recover the source emission rates and locations for 4 separate source patterns over the ~120m x 120m test area. Our Bayesian retrieval uses a Gaussian plume eddy dispersion model and Markov chain Monte Carlo approach to recover the source map solution and uncertainty bounds for all results. Accurate mapping and quantification of methane sources down to 1.2 kg/h was successfully demonstrated, even for sources outside the open path fan. A subsequent demonstration using a

T18


combined methane and carbon dioxide laser analyser will also be presented. This instrument was tested using controlled releases of methane and carbon dioxide simultaneously.

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T19


Open path FTIR measurements of greenhouse gas concentrations and fluxes in the atmosphere over kilometre pathlengths

David Griffith1, Nicholas Deutscher1, Travis Naylor1, Chris Caldow1, Hamish McDougal1, Alex Carter1, Jeremy Silver2, Peter Rayner2

1. University of Wollongong 2. University of Melbourne

Open path spectroscopic measurements of atmospheric trace gases complement in situ measurements at a point by probing an extended region of the atmosphere and providing line-averaged mole fractions over spatial scales better-matched to fine scale modelling techniques. Measurements of enhanced concentrations from fugitive gas plumes can be combined with small to regional scale meteorological modelling to invert concentration measurements into flux estimates. In previous work we demonstrated an open path monitoring system based on FTIR spectroscopy in the near infrared (NIR) over a pathlength of 1.5 km in an urban environment, the city of Heidelberg, Germany [1]. In this paper we describe further development of the optical system for open path FTIR spectroscopy which leads to significantly improved light throughput, precision and detection limits for atmospheric trace gases. The system achieves repeatabilities of ca. 0.25 ppm for CO2 and 2 ppb for CH4 over a 1.5 km open path, with uncalibrated biases of the order of 2% relative to relevant WMO scales. These figures are similar in magnitude to those achieved in the GAW-TCCON network for total column measurements based on solar remotes sensing. This paper describes the instrumental setup and demonstrates the accuracy and precision from a 3 month field trial. We pay particular attention to the differences between point and line-averaged measurements – when and to what extent is a point measurement representative of its km-scale surrounding area? The open path measurement system is currently operation in a rural location to assess the ability to detect and quantify fugitive emissions from a potential carbon capture and storage site.

Reference

[1] Griffith, D. W. T., Pöhler, D., Schmitt, S., Hammer, S., Vardag, S. N., and Platt, U.: Long open-path measurements of greenhouse gases in air using near-infrared Fourier transform spectroscopy, Atmos. Meas. Tech., 11, 1549-1563, 10.5194/amt-11-1549-2018, 2018.

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Open path FTIR measurements of greenhouse gas concentrations and fluxes in the atmosphere over kilometre pathlengths

David Griffith1, Nicholas Deutscher1, Travis Naylor1, Chris Caldow1, Hamish McDougal1, Alex Carter1, Jeremy Silver2, Peter Rayner2

1. University of Wollongong 2. University of Melbourne

Open path spectroscopic measurements of atmospheric trace gases complement in situ measurements at a point by probing an extended region of the atmosphere and providing line-averaged mole fractions over spatial scales better-matched to fine scale modelling techniques. Measurements of enhanced concentrations from fugitive gas plumes can be combined with small to regional scale meteorological modelling to invert concentration measurements into flux estimates. In previous work we demonstrated an open path monitoring system based on FTIR spectroscopy in the near infrared (NIR) over a pathlength of 1.5 km in an urban environment, the city of Heidelberg, Germany [1]. In this paper we describe further development of the optical system for open path FTIR spectroscopy which leads to significantly improved light throughput, precision and detection limits for atmospheric trace gases. The system achieves repeatabilities of ca. 0.25 ppm for CO2 and 2 ppb for CH4 over a 1.5 km open path, with uncalibrated biases of the order of 2% relative to relevant WMO scales. These figures are similar in magnitude to those achieved in the GAW-TCCON network for total column measurements based on solar remotes sensing. This paper describes the instrumental setup and demonstrates the accuracy and precision from a 3 month field trial. We pay particular attention to the differences between point and line-averaged measurements – when and to what extent is a point measurement representative of its km-scale surrounding area? The open path measurement system is currently operation in a rural location to assess the ability to detect and quantify fugitive emissions from a potential carbon capture and storage site.

Reference

[1] Griffith, D. W. T., Pöhler, D., Schmitt, S., Hammer, S., Vardag, S. N., and Platt, U.: Long open-path measurements of greenhouse gases in air using near-infrared Fourier transform spectroscopy, Atmos. Meas. Tech., 11, 1549-1563, 10.5194/amt-11-1549-2018, 2018.

T20


Study of error and sensitivity of short-term variation in XCO2 observed by Anmyeondo station Young -Suk Oh1, David Griffith2, Sebastien Roche3, Dmitry Belikov4, Kimbrly Strong3, Samuel Takele Keneal1, Lev Labzovskii1, Voltaire Velazco2, Haeyoung Lee1, Kyu-Sun Chung5, Tae-Young Goo1, Young-Hwa Byun1 1. National Institute of Meteorological Sciences 2. University of Wollongong 3. University of Toronto 4. National Institute for Environmental 5. Hanyang University

The Total Carbon Column Observing Network (TCCON) is a monitoring network that deploys ground-based Fourier transform (g-b FTS) spectrometers in the near-infrared (NIS) spectra of sun. Due to strong necessity in carbon cycle understanding, TCCON FTS instruments have been widely deployed for satellite validation of CO2 measurements and for CO2 variation characterization. The role of East Asia in carbon cycle is essential as the region is responsible for 30% of carbon emissions worldwide and exhibits the strongest CO2 amplitude in the world. From this standpoint, Anmyeondo station (AMY) in Korea is one of the key TCCON sites in the world (measuring CO2 using g-b FTS since 2013) located in the downwind direction from the main carbon source region. It is therefore required to quantify the spatial footprint of the FTS CO2 observations for AMY in details. Detailed investigation of AMY footprint is needed since previously quantified footprints (annual-based) at such coastal sites are temporally too coarse and seasonal variability of footprint should be resolved. As a coastal site facing ocean in the west and landmass in the east, the result the footprint sensitivity of AMY TCCON site to the surrounding emission in the land part would be potentially useful for quantifying the relative strength of CO2 signal in the nearby source region. Due to the complexity of the terrain structure, the footprint sensitivity of this site will account different layers in lower troposphere with high spatial resolution. To this end, we apply Eulerian three-dimensional transport model and Lagrangian particle dispersion model method for 2015 to 2018 years to determine the CO2 observation footprint in AMY station. Key words: AMT station, footprint, FTS CO2, carbon source, carbon cycle.

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T21


Principle, calibration and preliminary results of ground-based atmospheric CO2 monitoring instrument using spatial heterodyne spectroscopy

Zhiwei Li1, Hailiang Shi1, Hanhan Ye1, Haiyan Luo1

1. Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences

Passive optical remote sensing of 1.57um band fingerprint solar spectrum reflected from the earth's surface is one of the main methods to detect atmospheric CO2 column concentration. Because of the low concentration of CO2 in the atmosphere and the small temporal and spatial variation, it is necessary for the instrument to have hyperspectral resolution and high signal-to-noise ratio. Spatial heterodyne spectroscopy is easy to realize hyperspectral resolution, has large light flux, and has no moving parts and arbitrary band selection. Many teams in different countries and regions have carried out this technology in astronomical exploration, remote sensing of atmospheric trace gases, atmospheric temperature, humidity and wind detection and many other fields. Anhui Institute of Optics and Machinery, Chinese Academy of Sciences, is committed to the research and development of advanced technologies and instruments in the fields of Atmospheric optics, Environmental Optics and Optical remote sensing. In 2005, our laboratory began to pay attention to the spatial heterodyne spectroscopy, and discussed the feasibility of using this technology to detect atmospheric CO2. A ground-based atmospheric CO2 concentration measuring instrument based on this technology was successfully developed. This paper first introduces the basic and characteristics of this technology, then gives the technical parameters of the principle prototype developed by the laboratory, and states in detail the spectral calibration of the full-band response characteristics of the instrument using the tunable uniform surface light source developed by the laboratory, as well as the method and results of the radiometric calibration based on the large-aperture and high-stability integral sphere. As a result, the feasibility of using this instrument to detect atmospheric CO2 concentration was analyzed from the accuracy of radiation and spectral calibration. The verification test of different atmospheric CO2 concentration detection is carried out by using the atmospheric environment simulation calibration equipment which accurately controls the temperature and pressure to determine the gas concentration in the laboratory. Finally, the typical outdoor measurement spectrum and CO2 concentration detection results of the instrument are given. Spaceborne remote sensing can compensate for the shortcomings of ground-based measurement in time and space coverage. The Greenhouse gas Monitoring Instrument load based on spatial heterodyne spectroscopy was launched into orbit in 2018. The optimization and verification of data products are being carried out in the hope of providing basic data for global greenhouse gas source and sink analysis in the future.

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Principle, calibration and preliminary results of ground-based atmospheric CO2 monitoring instrument using spatial heterodyne spectroscopy

Zhiwei Li1, Hailiang Shi1, Hanhan Ye1, Haiyan Luo1


Passive optical remote sensing of 1.57um band fingerprint solar spectrum reflected from the earth's surface is one of the main methods to detect atmospheric CO2 column concentration. Because of the low concentration of CO2 in the atmosphere and the small temporal and spatial variation, it is necessary for the instrument to have hyperspectral resolution and high signal-to-noise ratio. Spatial heterodyne spectroscopy is easy to realize hyperspectral resolution, has large light flux, and has no moving parts and arbitrary band selection. Many teams in different countries and regions have carried out this technology in astronomical exploration, remote sensing of atmospheric trace gases, atmospheric temperature, humidity and wind detection and many other fields. Anhui Institute of Optics and Machinery, Chinese Academy of Sciences, is committed to the research and development of advanced technologies and instruments in the fields of Atmospheric optics, Environmental Optics and Optical remote sensing. In 2005, our laboratory began to pay attention to the spatial heterodyne spectroscopy, and discussed the feasibility of using this technology to detect atmospheric CO2. A ground-based atmospheric CO2 concentration measuring instrument based on this technology was successfully developed. This paper first introduces the basic and characteristics of this technology, then gives the technical parameters of the principle prototype developed by the laboratory, and states in detail the spectral calibration of the full-band response characteristics of the instrument using the tunable uniform surface light source developed by the laboratory, as well as the method and results of the radiometric calibration based on the large-aperture and high-stability integral sphere. As a result, the feasibility of using this instrument to detect atmospheric CO2 concentration was analyzed from the accuracy of radiation and spectral calibration. The verification test of different atmospheric CO2 concentration detection is carried out by using the atmospheric environment simulation calibration equipment which accurately controls the temperature and pressure to determine the gas concentration in the laboratory. Finally, the typical outdoor measurement spectrum and CO2 concentration detection results of the instrument are given. Spaceborne remote sensing can compensate for the shortcomings of ground-based measurement in time and space coverage. The Greenhouse gas Monitoring Instrument load based on spatial heterodyne spectroscopy was launched into orbit in 2018. The optimization and verification of data products are being carried out in the hope of providing basic data for global greenhouse gas source and sink analysis in the future.

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Trace gas measurements at the U.S. Southern Great Plains DOE Atmospheric Radiation Measurement Facility using an in situ FTIR: lesson learned after a 6-year deployment

Sebastien Biraud1, Ken Reichl1, Andrew Moyes1, and David Griffith2

1Lawrence Berkeley National Laboratory, Berkeley, CA 2University of Wollongong, Wollongong, Australia

The Department of Energy’s (DOE) Atmospheric Radiation Measurement (ARM) Program is a key component of the DOE’s research strategy to address global climate change. The ARM Program is a highly focused observational and analytical research effort that compares observations with model calculations in the interest of accelerating improvements in both observational methodology and General Circulation Models (GCMs) and related models. The objective of the ARM Program is to provide an experimental testbed for the study of important atmospheric effects, particularly cloud, radiative processes, land-atmosphere interactions, and testing parameterizations of these processes for use in climate change models. The ARM Program Climate Research Facility was initially composed of fixed sites and mobile facilities at which routine measurements are made on an operational basis and readily available through the ARM [11archive (http://www.arm.gov). Here we will present observations of mixing ratios collected in the Southern Great Plains (SGP) of the United since 2001, with an emphasis on the last six year of the record when an ECOTECH in situ FTIR (spectronus) was installed at the site. We will focus on the performances of this instrument as well as lessons learned from its field deployment.

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Atmospheric 14CO2 Southern Hemisphere latitudinal gradient over recent decades

Rachel Corran1, Jocelyn Turnbull2, Sara Mikaloff-Fletcher3

1. GNS Science, NZ , Victoria University of Wellington, NZ 2. GNS Science, NZ, CIRES, University of Colorado at Boulder, USA 3. NIWA

The net carbon uptake of the Southern Ocean is characterised by the combination of outgassing of CO2 from carbon-rich deep waters and sequestration of anthropogenic carbon into surface waters. Atmospheric radiocarbon dioxide (14CO2) in the Southern Hemisphere is sensitive to release of CO2 from the upwelling of ‘old’ 14C-free carbon-rich deep waters at high southern latitudes, but is insensitive to CO2 uptake into the ocean. Thus 14CO2 can be used as a tracer of the upwelling observed to isolate the outgassing carbon component. The Southern Ocean region is under-sampled for 14CO2 measurements, with sparse long-term atmospheric sampling sites and a few shipboard flask measurements. We therefore exploit tree rings, which faithfully record the 14C content of atmospheric CO2 with annual resolution, to reconstruct of 14CO2 back in time. Our tree ring derived 14CO2 results have comparable measurement accuracy to atmospheric 14CO2 measurements. We present new 14C measurements of tree rings from eight coastal sites in New Zealand and Chile, spanning a latitudinal range of 41°S to 55°S. These allow us to reconstruct the atmospheric 14CO2 Southern Hemisphere latitudinal gradient over recent decades and investigate the temporal and spatial variability of atmospheric 14CO2 data in the Southern Ocean region.

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Atmospheric 14CO2 Southern Hemisphere latitudinal gradient over recent decades

Rachel Corran1, Jocelyn Turnbull2, Sara Mikaloff-Fletcher3

1. GNS Science, NZ , Victoria University of Wellington, NZ 2. GNS Science, NZ, CIRES, University of Colorado at Boulder, USA 3. NIWA

The net carbon uptake of the Southern Ocean is characterised by the combination of outgassing of CO2 from carbon-rich deep waters and sequestration of anthropogenic carbon into surface waters. Atmospheric radiocarbon dioxide (14CO2) in the Southern Hemisphere is sensitive to release of CO2 from the upwelling of ‘old’ 14C-free carbon-rich deep waters at high southern latitudes, but is insensitive to CO2 uptake into the ocean. Thus 14CO2 can be used as a tracer of the upwelling observed to isolate the outgassing carbon component. The Southern Ocean region is under-sampled for 14CO2 measurements, with sparse long-term atmospheric sampling sites and a few shipboard flask measurements. We therefore exploit tree rings, which faithfully record the 14C content of atmospheric CO2 with annual resolution, to reconstruct of 14CO2 back in time. Our tree ring derived 14CO2 results have comparable measurement accuracy to atmospheric 14CO2 measurements. We present new 14C measurements of tree rings from eight coastal sites in New Zealand and Chile, spanning a latitudinal range of 41°S to 55°S. These allow us to reconstruct the atmospheric 14CO2 Southern Hemisphere latitudinal gradient over recent decades and investigate the temporal and spatial variability of atmospheric 14CO2 data in the Southern Ocean region.

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Inter-comparison of O2/N2 scales among AIST, NIES, TU, and SIO using primary standard mixtures with less than 5 per meg uncertainty for δ(O2/N2)

Nobuyuki Aoki1, Shigeyuki Ishidoya2, Yasunori Tohjima3, Shinji Morimoto4, Ralph F. Keeling5, Adam Cox5, Shuichiro Takebayashi4, Shohei Murayama2

1. National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology (NMIJ/AIST) 2. Environmental Management Research Institute, National Institute of Advanced Industrial Science and Technology (AIST) 3. National Institute for the Environmental Studies (NIES) 4. Center for Atmospheric and Oceanic Studies, Graduate School of Science, Tohoku University (TU) 5. Scripps Institution of Oceanography

Preparing primary standard mixtures with less than 5 per meg uncertainty for δ(O2/N2) is challenging, resulting in the atmospheric δ(O2/N2) being reported against laboratory dependent arbitral O2/N2 scale, of which precise span and absolute value are unknown. This makes it difficult to compare directly the various δ(O2/N2) values reported by different laboratories. But recently, we have developed a technique to gravimetrically prepare primary standard mixtures for atmospheric O2 with a standard uncertainty of 5 per meg (Aoki et al., 2019), allowing us to precisely compare the O2/N2 scale of each laboratory. Using the five developed primary standards, inter-comparison of O2/N2 scales of four laboratories (AIST, NIES, TU, and SIO) was implemented from 2017 to 2018. Drift of the O2/N2 ratios in the standards through the experiment were confirmed to be less than the uncertainties of the O2/N2 ratios by measuring them using a mass spectrometer and a paramagnetic oxygen analyser before and after the inter-comparison experiments. It was found that the O2/N2 span sensitivities among the four laboratories agreed to within ±2%. Detail differences of the O2/N2 scales of the respective laboratories from the gravimetric O2/N2 scale will be presented and discussed.

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Quantifying the span sensitivity of interferometric oxygen measurements

Ralph Keeling1, Stephen Walker1, Bill Paplawsky1

1. Scripps Institution of Oceanography

Measurements of changes in atmospheric O2/N2 ratio have been carried out since 1989 using a dual wavelength interferometric method employed at the Scripps Institution of Oceanography. This method depends on detecting changes in the relative refractivity of air between the two wavelengths (Hg-198 spectral lines at 254 and 436 nm). The measurements show that, from Jan 1990 to Jan 2019, atmospheric O2/N2 has decrease by ~680 per meg globally. Accurate quantification of this trend depends both on stable standards as well as on accurate calibration of the span sensitivity of the interferometric method. This span sensitivity has been assessed via three independent controls. The first control is theoretical, and depends on the refractivities of air and pure O2, and on the optical path difference (OPD) of the interferometer. The second control is based on bleeding a small controlled amount of a gravimetrically prepared O2:CO2 mixture into the air stream passing through the interferometer. In this “bleed test” method, the change in CO2 concentration, measured using a calibrated infrared analyzer, is used to assess the actual change in O2/N2 ratio in the interferometer. The third control is based on a suite of six gravimetrically-prepared air-like mixtures, with known O2/N2 ratios, which span a range of several thousand per meg in O2/N2 around ambient air values. These gravimetric mixtures were prepared in 1992 and 1993 at the NOAA-CMDL laboratory in Boulder using a dual-pan balance (Voland model HCE-10G DOW). In 2017, the span sensitivity calculated by the theoretical method was updated to correct an error in the refractivity data used previously, and to reflect an improved assessment of the small daily changes in the OPD. With this scale update, which was applied retrospectively to all O2/N2 data from 1989, the three controls on the span sensitivity agree to within ~1% with each other.

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Quantifying the span sensitivity of interferometric oxygen measurements

Ralph Keeling1, Stephen Walker1, Bill Paplawsky1


Measurements of changes in atmospheric O2/N2 ratio have been carried out since 1989 using a dual wavelength interferometric method employed at the Scripps Institution of Oceanography. This method depends on detecting changes in the relative refractivity of air between the two wavelengths (Hg-198 spectral lines at 254 and 436 nm). The measurements show that, from Jan 1990 to Jan 2019, atmospheric O2/N2 has decrease by ~680 per meg globally. Accurate quantification of this trend depends both on stable standards as well as on accurate calibration of the span sensitivity of the interferometric method. This span sensitivity has been assessed via three independent controls. The first control is theoretical, and depends on the refractivities of air and pure O2, and on the optical path difference (OPD) of the interferometer. The second control is based on bleeding a small controlled amount of a gravimetrically prepared O2:CO2 mixture into the air stream passing through the interferometer. In this “bleed test” method, the change in CO2 concentration, measured using a calibrated infrared analyzer, is used to assess the actual change in O2/N2 ratio in the interferometer. The third control is based on a suite of six gravimetrically-prepared air-like mixtures, with known O2/N2 ratios, which span a range of several thousand per meg in O2/N2 around ambient air values. These gravimetric mixtures were prepared in 1992 and 1993 at the NOAA-CMDL laboratory in Boulder using a dual-pan balance (Voland model HCE-10G DOW). In 2017, the span sensitivity calculated by the theoretical method was updated to correct an error in the refractivity data used previously, and to reflect an improved assessment of the small daily changes in the OPD. With this scale update, which was applied retrospectively to all O2/N2 data from 1989, the three controls on the span sensitivity agree to within ~1% with each other.

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Outline of the UEA/ENV & CAMS/CMA Collaborative Research Project: Establishing a high Precision atmospheric Oxygen network in CHina (EPOCH)

Lingxi Zhou1, Andrew Manning2

1. CAMS/CMA 2. UEA/ENV

Atmospheric CO2 levels are increasing and O2 levels are decreasing globally due to fossil-fuel burning. O2 and CO2 are influenced by many of the same processes, particularly processes that involve the formation and destruction of organic matter, such as fuel burning, photosynthesis, and respiration. CO2 is additionally influenced, however, by inorganic reactions in seawater that have no impact on atmospheric O2. Measurements of O2 in the atmosphere are valuable mainly because they can help to unravel the relative importance of these two sorts of influences on rising CO2. Measurements of the changes in the atmospheric O2/N2 ratio are useful for constraining sources and sinks of CO2 and testing land/ocean biogeochemical models and study of climate change. The relative variations in the O2/N2 ratio are very small but can now be observed by at least six established analytical techniques plus the emerging technique of laser spectroscopy. There is considerable scientific value to be gained from different laboratories reporting O2/N2 measurements on a common scale. The O2/N2 community recognizes the Scripps O2 scale as the best candidate for a common reference. This presentation outlines work that carried out up to date by UEA/ENV, to design, assemble and install four atmospheric O2/N2 measurement systems in China in collaboration with CAMS/CMA. The project includes a 12-month data gathering, analysis and interpretation period, and includes building a system for preparing working standards. The in situ atmospheric O2/N2 systems that be built are the product of many years of development work by Dr. Manning, and existing systems under the control of ENV have been operating continuously at the Weybourne Atmospheric Observatory, UK (since 2008), the Cap San Lorenzo, Hamburg Süd container ship (since 2014), and at Halley Base, Antarctica (since January 2016).

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Challenges in maintaining the artefact-based stable isotope scale for δ13C with the aim to address GAW-WMO uncertainty requirements.

Sergey Assonov1, Manfred Groening1, Ales Fajgelj1, Colin Allison2

1. International Atomic Energy Agency (IAEA), Vienna, Austria 2. CSIRO Oceans and Atmosphere, Aspendale, Victoria 3195, Australia

WMO scales for greenhouse gas concentrations (GHGs: CO2, CH4, N2O) use a primary method (volumetric or gravimetric mixing) to prepare calibration mixtures, in this way these mixtures are SI-traceable (T & P and amount of substance). In contrast, the VPDB scale used for δ13C data of air-CO2 and air-methane is currently based on an artefact (13C/12C measured relative to VPDB, all is realised in relative way) and is, therefore, not traceable to SI. In other words, on cannot make calibration mixtures by mixing 13C and 12C entities. In practice the VPDB scale is realized using a primary reference material (RM), which is traceable to the historical artefact, and other international RMs that are traceable to the primary RM. Two significant impacts on the VPDB scale realization have occurred, after 2010 NBS19 was not available for sale at the IAEA, and in 2015 the VPDB scale-anchor (an RM: LSVEC) at negative δ13C value was found to be isotopically drifting [1]. This situation leads to the necessary development of suitable replacement RMs in order to guarantee the scale sustainability into the future [2, 3]. We present the revised, hierarchical, scheme for the VPDB scale realisation and plans for the development of new RMs. The scheme is based on a replacement primary RM, IAEA-603, and several new scale-anchors (presently three new carbonate RMs under development at the IAEA, there are plans for several pure CO2 RMs) with all values assigned in mutually consistent way with low uncertainty (note, high δ13C accuracy determinations depend on several specific corrections). This hierarchical scheme is similar to that used for the WMO GHG concentration scales; the hierarchy will provide a sustainable scale realisation, help to minimize the scale uncertainty and detect RM’ value drift, if any. It is important that the uncertainty assigned to each RM, and the scale in general, is minimized and robustly determined to address the WMO recommended data quality objectives (DQOs). (Note, this is a part of the overall Quality Assurance Scheme that we will present in an accompanying poster.) The DQOs (also known as data compatibility targets) for stable carbon isotope measurements of atmospheric CO2 and methane have been set [1, 2] at 0.01 ‰ and 0.02 ‰ for δ13C of air-CO2 and air-methane respectively; these values are those obtained with the best performing analytical method, stable isotope ratio mass-spectrometry. The DQO imply very strict requirements for the performance of analytical instruments, all measurement steps and the calibrations involved in producing final results. Up to now these target DQOs have not been demonstrated on real air samples, round-robin air cylinders [1, 2] or even on exchanges of pure CO2 between “expert” laboratories [4, 5]. While some components limiting the achievement of the target DQOs are laboratory specific, more efforts in developing “fit-for-purpose” RMs are required. In

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Challenges in maintaining the artefact-based stable isotope scale for δ13C with the aim to address GAW-WMO uncertainty requirements.



WMO scales for greenhouse gas concentrations (GHGs: CO2, CH4, N2O) use a primary method (volumetric or gravimetric mixing) to prepare calibration mixtures, in this way these mixtures are SI-traceable (T & P and amount of substance). In contrast, the VPDB scale used for δ13C data of air-CO2 and air-methane is currently based on an artefact (13C/12C measured relative to VPDB, all is realised in relative way) and is, therefore, not traceable to SI. In other words, on cannot make calibration mixtures by mixing 13C and 12C entities. In practice the VPDB scale is realized using a primary reference material (RM), which is traceable to the historical artefact, and other international RMs that are traceable to the primary RM. Two significant impacts on the VPDB scale realization have occurred, after 2010 NBS19 was not available for sale at the IAEA, and in 2015 the VPDB scale-anchor (an RM: LSVEC) at negative δ13C value was found to be isotopically drifting [1]. This situation leads to the necessary development of suitable replacement RMs in order to guarantee the scale sustainability into the future [2, 3]. We present the revised, hierarchical, scheme for the VPDB scale realisation and plans for the development of new RMs. The scheme is based on a replacement primary RM, IAEA-603, and several new scale-anchors (presently three new carbonate RMs under development at the IAEA, there are plans for several pure CO2 RMs) with all values assigned in mutually consistent way with low uncertainty (note, high δ13C accuracy determinations depend on several specific corrections). This hierarchical scheme is similar to that used for the WMO GHG concentration scales; the hierarchy will provide a sustainable scale realisation, help to minimize the scale uncertainty and detect RM’ value drift, if any. It is important that the uncertainty assigned to each RM, and the scale in general, is minimized and robustly determined to address the WMO recommended data quality objectives (DQOs). (Note, this is a part of the overall Quality Assurance Scheme that we will present in an accompanying poster.) The DQOs (also known as data compatibility targets) for stable carbon isotope measurements of atmospheric CO2 and methane have been set [1, 2] at 0.01 ‰ and 0.02 ‰ for δ13C of air-CO2 and air-methane respectively; these values are those obtained with the best performing analytical method, stable isotope ratio mass-spectrometry. The DQO imply very strict requirements for the performance of analytical instruments, all measurement steps and the calibrations involved in producing final results. Up to now these target DQOs have not been demonstrated on real air samples, round-robin air cylinders [1, 2] or even on exchanges of pure CO2 between “expert” laboratories [4, 5]. While some components limiting the achievement of the target DQOs are laboratory specific, more efforts in developing “fit-for-purpose” RMs are required. In

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particular, new RMs aimed at the realisation of the VPDB scale must have low uncertainties and fulfil the metrological traceability principle.

References

[1] GGMT-2015, GAW Report No. 229;

[2] GGMT-2017; GAW Report No. 242;

[3] Summary and recommendations from the IAEA Technical Meeting on the Development of Stable Isotope Reference Products (21–25 November 2016). Rapid Communications in Mass Spectrometry, 2018. 32(10): p. 827-830. https://doi.org/10.1002/rcm.8102

[4] “The International Atomic Energy Agency circulation of laboratory air standards for stable isotope comparisons: Aims, preparation and preliminary results”, In IAEA-TECDOC-1269 (2002), pp. 5-23. http://www-pub.iaea.org/MTCD/Publications/PDF/te_1269_web.pdf

[5] “What Have We Learnt about Stable Isotope Measurement from the IAEA CLASSIC?” In GAW Report No. 148 (2003), p 17 – 30; https://library.wmo.int/pmb_ged/wmo-td_1138.pdf

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Assuring quality in the measurement and reporting of stable isotope measurements of atmospheric carbon dioxide

Colin Allison1, Ray Langenfelds1, Sergey Assonov2, Sylvia Michel3, Duane Kitzis4

1. CSIRO Oceans & Atmosphere, Aspendale, Victoria, Australia 2. IAEA, Vienna, Austria 3. INSTAAR, Boulder, Colorado, USA 4. NOAA, Boulder, Colorado, USA

Of the forty-four laboratories that participated in the sixth WMO/IAEA Round Robin (RR6) only fifteen laboratories reported δ13C (and only thirteen reported δ18O) measurements of the CO2 [1] and only two of those laboratories submit multiple sets of measurement data to the WDCGG [2]. Further, the WDCGG accepts δ13C and δ18O (of CO2) data on two "scales": PDB and VPDB-CO2 (δ13C of CH4 data are also accepted on two scales: VPDB and VDPB-CO2). As the GGMT-2017 Meeting Report states "JRAS-06 is the recommended VPDB-CO2 scale realization for stable isotopes of CO2"[3], VPDB-CO2 should be the "scale" on which the δ13C and δ18O data are submitted. Both of the laboratories that submit multiple data sets to the WDCGG data have either implemented, or are implementing the JRAS-06 realization of the VPDB-CO2 scale and so should be reporting data on the same scale. A further situation arises in that differences between the fifteen laboratories that reported δ13C of CO2 data in RR6 significantly exceed the recommended targets for network compatibility (Table 1 in [3]). Is this "disagreement" a limiting factor in the submission of data to the WDCGG by RR participants? If so, what could be done to improve this situation? This presentation will illustrate an implementation of the JRAS-06 realization of the VPDB-CO2 scale and compare data from several laboratories to elaborate some difficulties that need to be overcome. Concluding remarks will emphasize the importance of a single calibration scale with robust uncertainty estimates for stable isotope measurements of CO2 in the upcoming seventh WMO/IAEA Round Robin (RR7) and other comparison activities, and probe the potential role of a WCC in this and other calibration activities.

References

[1] Data accessed on 5 July 2019 at (https://www.esrl.noaa.gov/gmd/ccgg/wmorr/wmorr_results.php)

[2] Data accessed on 5 July 2019 at https://gaw.kishou.go.jp/

[3] 19th WMO/IAEA Meeting on Carbon Dioxide, Other Greenhouse Gases and Related Measurement Techniques (GGMT-2017), GAW Report No. 242

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Assuring quality in the measurement and reporting of stable isotope measurements of atmospheric carbon dioxide

Colin Allison1, Ray Langenfelds1, Sergey Assonov2, Sylvia Michel3, Duane Kitzis4

1. CSIRO Oceans & Atmosphere, Aspendale, Victoria, Australia 2. IAEA, Vienna, Austria 3. INSTAAR, Boulder, Colorado, USA 4. NOAA, Boulder, Colorado, USA

Of the forty-four laboratories that participated in the sixth WMO/IAEA Round Robin (RR6) only fifteen laboratories reported δ13C (and only thirteen reported δ18O) measurements of the CO2 [1] and only two of those laboratories submit multiple sets of measurement data to the WDCGG [2]. Further, the WDCGG accepts δ13C and δ18O (of CO2) data on two "scales": PDB and VPDB-CO2 (δ13C of CH4 data are also accepted on two scales: VPDB and VDPB-CO2). As the GGMT-2017 Meeting Report states "JRAS-06 is the recommended VPDB-CO2 scale realization for stable isotopes of CO2"[3], VPDB-CO2 should be the "scale" on which the δ13C and δ18O data are submitted. Both of the laboratories that submit multiple data sets to the WDCGG data have either implemented, or are implementing the JRAS-06 realization of the VPDB-CO2 scale and so should be reporting data on the same scale. A further situation arises in that differences between the fifteen laboratories that reported δ13C of CO2 data in RR6 significantly exceed the recommended targets for network compatibility (Table 1 in [3]). Is this "disagreement" a limiting factor in the submission of data to the WDCGG by RR participants? If so, what could be done to improve this situation? This presentation will illustrate an implementation of the JRAS-06 realization of the VPDB-CO2 scale and compare data from several laboratories to elaborate some difficulties that need to be overcome. Concluding remarks will emphasize the importance of a single calibration scale with robust uncertainty estimates for stable isotope measurements of CO2 in the upcoming seventh WMO/IAEA Round Robin (RR7) and other comparison activities, and probe the potential role of a WCC in this and other calibration activities.

References

[1] Data accessed on 5 July 2019 at (https://www.esrl.noaa.gov/gmd/ccgg/wmorr/wmorr_results.php)

[2] Data accessed on 5 July 2019 at https://gaw.kishou.go.jp/

[3] 19th WMO/IAEA Meeting on Carbon Dioxide, Other Greenhouse Gases and Related Measurement Techniques (GGMT-2017), GAW Report No. 242

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Comparison of isotope ratio measurement capabilities for CO2 isotopes: Sample preparation and characterization by isotope ratio infrared spectroscopy and mass-spectrometry

Joële Viallon1, Philippe Moussay1, Edgar Flores1, Ian Chubchenko2, Francesca Rolle3, TiQuiang Ziang4, Eric Mussel Webber5, Robert Ian Wielgosz1, Segey Assonov6, Manfre Groening6

1. BIPM 2. VNIIM 3. INRIM 4. NIM 5. NPL 6. IAEA

The characteristics and performance of a system to prepare up to ten 50 mL samples of pure CO2 with on-demand (desired) 13C/12C ratios by gas mixing will be described, together with an optimized calibration system for measurements by Isotope Ratio Infrared Spectroscopy (IRIS) that has allowed measurement of δ13C and δ18O values with 0.02‰ reproducibility (1 σ). The needs for improved quality infrastructure and appropriate reference gases for CO2 isotope ratio measurements (13C/12C and 18O/16O) has been a driver for recent research and development activities within the National Metrology Institutes, and the decision of the Gas Analysis Working Group of the CCQM to plan an international comparison (CCQM-P204) of capabilities of measurements of these quantities. The comparison will be coordinated by the BIPM, which has the task of preparing the comparison samples, and the IAEA, who will assign their isotopic composition on the VPDB-CO2 reference scale which is the international scale for δ13C and δ18O data reporting for atmospheric CO2 by Global Atmospheric Watch program at WMO. The BIPM has developed a preparation facility based on blending of different pure CO2 gases of different isotopic compositions, followed by cryogenic trapping and transfer to ten 50 mL cylinders. The target isotopic ratio 13C/12C can be adjusted by accurate gas mixing proportions known from flow measurements. A Carousel sampling system with bracketing reference gas calibration and dilution system has been designed at the BIPM to allow rapid and accurate analysis of prepared gas mixtures by IRIS (Delta Ray). A key feature of the calibration system is to maintain identical treatment of sample and reference gases allowing two-point instrument’ calibration for up to 14 samples, and appropriate flushing protocols to remove any biases from memory effects of previously sampled gases. Measurements are performed by the IRIS analyzer at a mole fraction of nominally 700 μmol/mol CO2 in air, by dilution of pure CO2 gas controlled by individual low-flow mass flow controllers (0.07 ml/min), and with a feedback loop to control mole fractions to ensure that differences between references and sample gas mole faction stay below 2 μmol/mol. This level of control is necessary to prevent biases in measured isotope ratios by IRIS, the magnitude of which has also been studied with a sensitivity study that is also reported. The Carousel and IRIS measurement’s linearity have

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been validated using pure CO2 samples prepared with the gas blending facility, covering a range in delta values of -1‰ to -45‰ vs VPDB, and in all cases measurement reproducibility over several days of testing of 0.02‰ or better (1 σ) were achieved for both δ13C and δ18O, with negligible memory effects. Value assignment on the VPDB-CO2 scale for δ13C and δ18O for end-member CO2 gases and mixtures will be performed at the IAEA by mass-spectrometry (MAT253 in high accuracy dual inlet mode) and traceable to the primary RM IAEA-603 (CO2 released by H3PO4 from marble carbonate). Preliminary measurements at the IAEA allowed an optimization of gas-storage containers and feasibility to perform measurements both by mass-spectrometry and IRIS. Results will be verified against independent NIST CO2 refence materials 8562-8564. Samples produced with the BIPM gas-mixing facility and characterized at the IAEA will be distributed to institutes participating in the CCQM-P204 comparison exercise, with measurements foreseen in 2020.

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been validated using pure CO2 samples prepared with the gas blending facility, covering a range in delta values of -1‰ to -45‰ vs VPDB, and in all cases measurement reproducibility over several days of testing of 0.02‰ or better (1 σ) were achieved for both δ13C and δ18O, with negligible memory effects. Value assignment on the VPDB-CO2 scale for δ13C and δ18O for end-member CO2 gases and mixtures will be performed at the IAEA by mass-spectrometry (MAT253 in high accuracy dual inlet mode) and traceable to the primary RM IAEA-603 (CO2 released by H3PO4 from marble carbonate). Preliminary measurements at the IAEA allowed an optimization of gas-storage containers and feasibility to perform measurements both by mass-spectrometry and IRIS. Results will be verified against independent NIST CO2 refence materials 8562-8564. Samples produced with the BIPM gas-mixing facility and characterized at the IAEA will be distributed to institutes participating in the CCQM-P204 comparison exercise, with measurements foreseen in 2020.

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Strategies to assess and reduce current inter-laboratory differences in δ13C-CH4 and δ2H-CH4 measurements in air samples

Peter Sperlich1, Gordon Brailsford1, Rowena Moss1, Tony Bromley1, Sally Gray1, Ross Martin1, Heiko Moossen2, Michael Rothe2, Willi Brand2, Sylvia Englund-Michel3, Bruce Vaughn3, James White3, Taku Umezawa4, Thomas Röckmann5, Carina van der Veen5, Euan Nisbet6, Rebecca Fisher6, Dave Lowry6

1. National Institute of Water and Atmospheric Research (NIWA), Wellington, New Zealand 2. Max-Planck-Institute for Biogeochemistry (MPI-BGC), Jena, Germany 3. Institute of Arctic and Alpine Research (INSTAAR), University of Colorado, Boulder, USA 4. National Institute for Environmental Studies, Ibaraki, Japan 5. Institute for Marine and Atmospheric research Utrecht (IMAU), Utrecht University, The Netherlands 6. Royal Holloway University of London, UK

The recent study by Umezawa et al. 2018 has highlighted significant inter-laboratory differences in both carbon and hydrogen isotope ratio measurements of atmospheric CH4. The main cause of the differences between the laboratories is that a set of unique reference gases is not available. Instead, laboratories developed their own strategies to reference their measurements to the international VPDB and VSMOW scales; based on a wide range of non-CH4 reference materials that were available at the time. Laboratory-specific differences in analytical techniques have furthermore added to the differences between laboratories. We discuss a round robin for isotope ratios in atmospheric CH4, which has recently been initiated by INSTAAR/NOAA and NIWA. This round robin is now underway and will provide the opportunity to assess current laboratory offsets. Furthermore, MPI-BGC and NIWA are leading a project to develop a strategy to provide a suite of community reference gases. It is intended for our community reference gases to be distributed amongst a wider group of project partners in the near future. Consequent iterations of the round robin will enable us to assess the effect of the community reference gases on reducing the inter-laboratory offsets.

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JRAS-06: Scale maintenance and keeping up with changing stable isotopic reference materials

Heiko Moossen1, Michael Rothe1, Juergen Richter1, Willi A. Brand1

1. Max Planck Institute for Biogeochemistry

One of the most critical aspects of measuring carbon isotopic signatures of atmospheric CO2 is the stringent standardisation procedure which is required. Without it, inter-laboratory δ13C-/δ18O-CO2 comparisons are difficult at best, and impossible at worst. The stable isotope laboratory at the Max-Planck-Institute for Biogeochemistry (BGC-IsoLab) is the central calibration laboratory of the world metrological organisation / Global Atmospheric Watch (WMO/GAW) since 2015, and offers the Jena Reference Air Set (JRAS) to the scientific community. CO2 for this set of reference materials is evolved from two in-house carbonate standards and diluted into CO2-free matrix air producing CO2 in air standards. The evolved CO2 from the in-house standards has been linked to the VPDB-CO2 scale by NBS 19 measurements done in 2003/2004. The CO2 in air scale is called JRAS-06 as it has been in operation since 2006. Here we present new data showing that the link between the JRAS-06 and VPDB-CO2 scale is still valid 15 years after the primary standardisation was established. We discuss the effects changing primary standards have on the VPDB-CO2 scale and highlight some of the intricacies that are associated with high precision isotope ratio measurements.

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JRAS-06: Scale maintenance and keeping up with changing stable isotopic reference materials

Heiko Moossen1, Michael Rothe1, Juergen Richter1, Willi A. Brand1

1. Max Planck Institute for Biogeochemistry

One of the most critical aspects of measuring carbon isotopic signatures of atmospheric CO2 is the stringent standardisation procedure which is required. Without it, inter-laboratory δ13C-/δ18O-CO2 comparisons are difficult at best, and impossible at worst. The stable isotope laboratory at the Max-Planck-Institute for Biogeochemistry (BGC-IsoLab) is the central calibration laboratory of the world metrological organisation / Global Atmospheric Watch (WMO/GAW) since 2015, and offers the Jena Reference Air Set (JRAS) to the scientific community. CO2 for this set of reference materials is evolved from two in-house carbonate standards and diluted into CO2-free matrix air producing CO2 in air standards. The evolved CO2 from the in-house standards has been linked to the VPDB-CO2 scale by NBS 19 measurements done in 2003/2004. The CO2 in air scale is called JRAS-06 as it has been in operation since 2006. Here we present new data showing that the link between the JRAS-06 and VPDB-CO2 scale is still valid 15 years after the primary standardisation was established. We discuss the effects changing primary standards have on the VPDB-CO2 scale and highlight some of the intricacies that are associated with high precision isotope ratio measurements.

T32


JRAS-06 or bust! The INSTAAR Stable Isotope Lab revises its ties to primary reference materials and releases a revised data set of stable isotopes of CO2

Sylvia Michel1, Pieter Tans2, John Miller2, Heiko Moossen3, Kevin Rozmiarek1, Alyssa Johnson1, Bruce Vaughn1, James White1

1. INSTAAR, University of Colorado 2. NOAA ESRL, Global Monitoring Division 3. Max Planck Institute

The INSTAAR Stable Isotope Lab (SIL) has a twenty-nine year record of measurements of stable isotopes of carbon dioxide from NOAA’s Global Greenhouse Gas Reference Network. Until now we have been tied to the VPDB scale via in-house measurements of the primary reference material NBS19, a calcite. We propagated our local scale through time with careful measurements of our daily standards (CO2 in ambient air) to previous standards. Long-term surveillance cylinders validated consistency of the scale over time with no drift. We can now use those surveillance cylinders to move our entire dataset to the JRAS-06 realization of the VPDB scale for δ13C and δ18O of CO2, produced by the Central Calibration Laboratory at MPI-BGC, in Jena, Germany. Here we show how this affects our data – changes of - 0.02 ‰ change for δ13C and -0.13 ‰ for δ18O (with only slight variation over time due to specific standards). This improves our comparability and compatibility with other laboratories on the JRAS-06 scale, as shown by intercomparisons and a reanalysis of the 5th Round Robin. We also account for uncertainty in our propagation of JRAS-06 back in time, as well as other sources of uncertainty in our measurements. Our ability to reprocess data is possible because of careful archiving of data accessible through a relational data base that allows QA/QC retrospectively. This marks a very important step forward for the stable isotope community in achieving WMO compatibility goals, which have been pursued for many years.

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Design and implementation of an enhanced observation network in New Zealand. Gordon Brailsford1, Sara Mikaloff Fletcher1, Mike Harvey1, Sally Gray1, Rowena Moss1, Sylvia Nichol1, Peter Sperlich1, Jocelyn Turnbull2 1. National Institute of Water and Atmosphere, Wellington, New Zealand 2. GNS Science, Lower Hutt, New Zealand

The New Zealand greenhouse gas observation network has historically focused on baseline observations. The geographic isolation of N.Z. means air coming on to the country in southerly airflows is representative of air masses in the mid latitudes of the Southern Hemisphere. This network remains a cornerstone of the New Zealand research programme with regular contributions to global databases like WDCGG. New Zealand, like all countries must determine a national inventory of greenhouse gases reported to UNFCCC, to date this has been accomplished through bottom up methods. Atmospheric methods can add valuable information to national inventory assessment as discussed in the 2019 refinement to the IPCC guidelines for national greenhouse gas inventories. They can provide important verification and are complementary rather than a replacement. An initial study that incorporated atmospheric observations and an inversion model provided a national atmospheric inversion of CO2. This has demonstrated the ability of top down approaches to compliment bottom up methods in determining the national inventory. Following this pilot study we have developed the Carbon Watch NZ programme: a multi-institute collaboration to provide observation based information on the New Zealand carbon balance. The Carbon Watch NZ programme aims are to implement an observation network that provides greenhouse gas observations that are modelled to interpret the contributions to the national atmospheric carbon budget. The network design enhances the national level observation coverage, and nests within that sub-networks that investigate three environments that play important roles in the New Zealand carbon balance. The role of forests, both planted and indigenous will be studied in several regions through a combination of in situ observation and flask collections for later analysis. Urban environments will be studied in Auckland where at least three in situ stations will be established and supported by flask collections for a suite of analyses that will inform on both the origin and fate of carbon in the New Zealand urban setting. With a dominance of agriculture in New Zealand, pastures are the third key sector to be studied. Fluxes of CO2 from a range of grassland types will be assessed and upscaled via a land-use model to provide estimates of grassland carbon exchange. Observations of (ruminant) methane will also be made with the aim of determining the magnitude of change that can be detected to assess future mitigation strategies. All of these gas observations will be supported by simulations from land and ocean models providing prior estimates to a scalable high-resolution atmospheric inversion model to inform on processes and the potential of mitigation strategies.

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Design and implementation of an enhanced observation network in New Zealand. Gordon Brailsford1, Sara Mikaloff Fletcher1, Mike Harvey1, Sally Gray1, Rowena Moss1, Sylvia Nichol1, Peter Sperlich1, Jocelyn Turnbull2 1. National Institute of Water and Atmosphere, Wellington, New Zealand 2. GNS Science, Lower Hutt, New Zealand

The New Zealand greenhouse gas observation network has historically focused on baseline observations. The geographic isolation of N.Z. means air coming on to the country in southerly airflows is representative of air masses in the mid latitudes of the Southern Hemisphere. This network remains a cornerstone of the New Zealand research programme with regular contributions to global databases like WDCGG. New Zealand, like all countries must determine a national inventory of greenhouse gases reported to UNFCCC, to date this has been accomplished through bottom up methods. Atmospheric methods can add valuable information to national inventory assessment as discussed in the 2019 refinement to the IPCC guidelines for national greenhouse gas inventories. They can provide important verification and are complementary rather than a replacement. An initial study that incorporated atmospheric observations and an inversion model provided a national atmospheric inversion of CO2. This has demonstrated the ability of top down approaches to compliment bottom up methods in determining the national inventory. Following this pilot study we have developed the Carbon Watch NZ programme: a multi-institute collaboration to provide observation based information on the New Zealand carbon balance. The Carbon Watch NZ programme aims are to implement an observation network that provides greenhouse gas observations that are modelled to interpret the contributions to the national atmospheric carbon budget. The network design enhances the national level observation coverage, and nests within that sub-networks that investigate three environments that play important roles in the New Zealand carbon balance. The role of forests, both planted and indigenous will be studied in several regions through a combination of in situ observation and flask collections for later analysis. Urban environments will be studied in Auckland where at least three in situ stations will be established and supported by flask collections for a suite of analyses that will inform on both the origin and fate of carbon in the New Zealand urban setting. With a dominance of agriculture in New Zealand, pastures are the third key sector to be studied. Fluxes of CO2 from a range of grassland types will be assessed and upscaled via a land-use model to provide estimates of grassland carbon exchange. Observations of (ruminant) methane will also be made with the aim of determining the magnitude of change that can be detected to assess future mitigation strategies. All of these gas observations will be supported by simulations from land and ocean models providing prior estimates to a scalable high-resolution atmospheric inversion model to inform on processes and the potential of mitigation strategies.

T34


Evolving Greenhouse gases observational network in India

Yogesh Tiwari1, Smrati Gupta1, Santanu Halder1

1. Indian Institute of Tropical Meteorology, Pune, India

The only land station, Cape Rama (CRI) Goa in India which operated for more than 10 years has been discontinued in 2012. There were no Greenhouse gases GHGs observations over central and western boundary of India. LSCE France in collaboration with CMMACS and IIA Bangalore India started few monitoring sites in 2007 but they were mainly centered over far eastern island, east coast or extreme northern part of India. Most of these sites do not fully sample Indian sub-continent air-masses (we have shown such evidence in our publications). LSCE in Paris has done routine glass flasks sample analysis collected at weekly interval at these sites. Few of LSCE sites in India are non-operational at the moment. To fill the gap, we have already initiated various projects for Greenhouse gases monitoring at the surface (in-situ, and glass flask) and in upper atmosphere (in-situ using aircraft) over different parts of India. Also, we have established glass flask air sample analysis lab, equipped with Gas Chromatography (GC) instrument, at the IITM Pune in 2009. We started first surface site at Sinhagad (SNG) Pune in November 2009 where we collect glass flask sample on weekly interval and analyze at GC lab at Pune India. SNG is currently operational and data is available till recent period (2019). We use NOAA Boulder USA standards for calibration of observations. Also, GC lab is part of inter calibration program among the WMO/GAW laboratories in Asia among Japan, China, Korea. Further, we have installed 72-meter tall tower at the outskirts of Bhopal over central India where we are monitoring soil CO2 and atmospheric GHGs as well as its isotope. Apart from this we are monitoring various other parameters related to atmosphere and soil. This site is first test-bed site for atmospheric research in India. Further, for upper atmospheric GHGs monitoring, we have started airplane campaigns in 2014 where we have monitored horizontal and vertical profiles GHGs over different part of India using Picarro G2401-m flight instrument. At the same time we have already established GHGs transport modeling frame-work at the IITM Pune server where we are developing global as well as high resolution modeling approach to estimate GHGs sources and sinks over the Indian sub-continent and adjoining regions. Further, a surface monitoring network is always per-requisite in India, therefore we have already initiated to install systematic GHGs monitoring network in the country. Under this network, we are establishing various monitoring sites (almost 10 observational sites) at different locations in India. These sites will be equipped with in-situ GHGs monitoring instruments as well as various other weather monitoring instruments measure soil and atmospheric components. Therefore, we are trying to fill the cavity arose due to lack of GHGs observational network in India in the past. In this study we will present available outputs and discuss about efforts on establishing GHGs monitoring network in India.

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Collection of CO2 measurements in Europe for the study of the drought of Summer 2018

Michel Ramonet1, Alex Vermeulen2, Léonard Rivier1, Philippe Ciais1

1. LSCE, Université Paris Saclay, CNRS/CEA/UVSQ, Gif-sur-Yvette, France 2. ICOS ERIC Carbon Portal, University of Lund, Sweden

During the summer of 2018 a widespread drought developed over Northern and Central Europe. The significant increase in temperature and the reduction of soil moisture have disturbed CO2 exchanges with terrestrial ecosystems by various mechanisms such as the reduction of photosynthesis, or fires which were particularly important in Sweden at the end of July 2018. In this study we characterize the resulting perturbation of the seasonal cycle of the atmospheric CO2 concentrations. This extreme meteorological episode has been the driving force behind the collection of all atmospheric CO2 concentration measurements in Europe, aiming to investigate how large scale ecosystem flux anomalies impacted CO2 gradients between stations. As part of the implementation of the ICOS European infrastructure several new stations have been set up since 2015, providing an unprecedented network density to study this extreme event, compared to previous drought events in 2003 and 2015. We have merged the ICOS dataset with previous measurements made at the same sites before the development of ICOS, and with stations not part of ICOS but contributing to other international dataset like WDCGG, OBSPACK or to national networks. In total, the dataset includes 49 measurement sites, including 20 tall towers with multiple sampling levels, representing more than 5 million hourly data. The quality of the different dataset gathered may differ from site to site, and year to year. As part of RINGO European project we attempt to assess the quality of 10 long term time series by using the available information (e.g. calibration sequences, intercomparisons, target gases, comparison to flask sampling program, etc…). We will present this analysis of historical dataset, and propose the way forward to annually upgrade this European dataset. As a result of our analysis, the summer minimum of CO2 concentration associated with the Drought episode was less marked (by 3 to 5 ppm) in 2018 in most of the stations located in northern Europe. On the other hand, the CO2 build up phase after July was slower in 2018 compared to 2017, suggesting an extension of the late growing season. The few long time series available are used to put into perspective the amplitude of the CO2 anomaly observed in 2018 compared to previous European droughts in 2003, 2010 and 2015.

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Collection of CO2 measurements in Europe for the study of the drought of Summer 2018

Michel Ramonet1, Alex Vermeulen2, Léonard Rivier1, Philippe Ciais1

1. LSCE, Université Paris Saclay, CNRS/CEA/UVSQ, Gif-sur-Yvette, France 2. ICOS ERIC Carbon Portal, University of Lund, Sweden

During the summer of 2018 a widespread drought developed over Northern and Central Europe. The significant increase in temperature and the reduction of soil moisture have disturbed CO2 exchanges with terrestrial ecosystems by various mechanisms such as the reduction of photosynthesis, or fires which were particularly important in Sweden at the end of July 2018. In this study we characterize the resulting perturbation of the seasonal cycle of the atmospheric CO2 concentrations. This extreme meteorological episode has been the driving force behind the collection of all atmospheric CO2 concentration measurements in Europe, aiming to investigate how large scale ecosystem flux anomalies impacted CO2 gradients between stations. As part of the implementation of the ICOS European infrastructure several new stations have been set up since 2015, providing an unprecedented network density to study this extreme event, compared to previous drought events in 2003 and 2015. We have merged the ICOS dataset with previous measurements made at the same sites before the development of ICOS, and with stations not part of ICOS but contributing to other international dataset like WDCGG, OBSPACK or to national networks. In total, the dataset includes 49 measurement sites, including 20 tall towers with multiple sampling levels, representing more than 5 million hourly data. The quality of the different dataset gathered may differ from site to site, and year to year. As part of RINGO European project we attempt to assess the quality of 10 long term time series by using the available information (e.g. calibration sequences, intercomparisons, target gases, comparison to flask sampling program, etc…). We will present this analysis of historical dataset, and propose the way forward to annually upgrade this European dataset. As a result of our analysis, the summer minimum of CO2 concentration associated with the Drought episode was less marked (by 3 to 5 ppm) in 2018 in most of the stations located in northern Europe. On the other hand, the CO2 build up phase after July was slower in 2018 compared to 2017, suggesting an extension of the late growing season. The few long time series available are used to put into perspective the amplitude of the CO2 anomaly observed in 2018 compared to previous European droughts in 2003, 2010 and 2015.

T36


Observation of atmospheric carbon monoxide at the background stations in China

Shuangxi Fang1, Minrui Guo2, Shuo Liu3

1. China Meteorological Administration 2. Beijing Normal University 3. Chinese Academy of Sciences

The carbon monoxide (CO) is an important indirect greenhouse gas as it influences the abundance of CO2 and CH4 through direct or indirect reactions. It has been involved in the China Meteorological Administration’s GHGs observation program since 2010, by using cavity ring-down spectroscopy (CRDS) technique. In this study, the CO observed at our four stations (Lin’an, Shangdianzi, Mt. Waliguan, and Shangri-La) are represented. The records indicate that, CO mole fractions at the stations close to the economic developed regions (Lin’an and Shangdianzi) are apparently higher than those at the remote sites, which is mainly from the anthropogenic emissions. The CO at these two stations displayed decreasing trends with values larger than 1.3 ppb yr-1 from 2010 to 2017. Due to the influence of Monsoons and transport from mega cities, the CO at the SDZ station (near Beijing) present a different seasonal pattern comparing to the northern hemisphere, with the maximum in July and minimum in October. The Mt. Waliguan station is a WMO/GAW global station and the observations are generally used to represent the conditions over the Eurasia. Although the yearly average CO at this site is relatively low (115 to 135 ppb), the atmospheric CO was frequently influenced by transport from the mega cities located at the northeast and east. The Shangri-La station is located at the southern edge of the Qinghai-Tibet plateau, the atmospheric CO is mainly influenced by air mass form the Myanmar, India and other south Asian countries. As a result, the CO at this site are dominantly representing the conditions at the southern edge of the Qinghai-Tibet plateau instead of the conditions over the central plateau.

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CO2 and air quality over megacity: a case study of Seoul, Korea

Sojung Sim1, Sujong Jeong1

1. Seoul National University

Since greenhouse gas CO2 and air pollutants mainly come from anthropogenic sources in cities, monitoring urban CO2 could have the potential to understand air quality. However, our understanding on how greenhouse gases and air pollutants are related over the city is still limited. In this study, we evaluate the relationships between observed CO2 and pollutants including CO, NO2, and PM2.5 in the central area of Seoul, Korea during the winter of 2018-2019. We calculated the excess emission by subtracting the baseline value from the measured one for local enhancement only. The result shows △CO and △NO2 are highly correlated (R > 0.7 and 0.6, respectively) with △CO2 at the same time. Coefficient of correlation between △CO2 and △PM2.5 continues to increase and has a maximum correlation (R > 0.3) after 3 hours when the time of △CO2 is fixed. This is thought to be a delay for production of PM2.5 by the primary particulate matter emitted with CO2. Also, the ratio of △pollutant to △CO2 represents the air pollutants emitted by the fuel consumed, which can be used to guess emission characteristics of Seoul by comparing it with previous studies. The △CO:△CO2 (6 ppbppm-1) is slightly lower compared to ground-level value in Utah (7.38 ppb ppm-1) and KORUS-AQ airborne one in Seoul (9.09 ppb ppm-1). And the △NO2:△CO2 (0.37 ppb ppm-1) is significantly lower in Seoul compared to tunnel traffic emission value in Paris (3.32 ppb ppm-1), but △PM2.5:△CO2 (0.19 μgm-3ppm-1) is similar with the ratio in Utah (0.18 μgm-3

ppm-1). Because we focus on the city scale and the measurement points of CO2 and air pollutants are different, ratios of this study can be lower than ones of previous studies, but result is still meaningful. Our results suggest that monitoring urban CO2 can serve as an internal indicator of urban air pollutants.

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CO2 and air quality over megacity: a case study of Seoul, Korea

Sojung Sim1, Sujong Jeong1


Since greenhouse gas CO2 and air pollutants mainly come from anthropogenic sources in cities, monitoring urban CO2 could have the potential to understand air quality. However, our understanding on how greenhouse gases and air pollutants are related over the city is still limited. In this study, we evaluate the relationships between observed CO2 and pollutants including CO, NO2, and PM2.5 in the central area of Seoul, Korea during the winter of 2018-2019. We calculated the excess emission by subtracting the baseline value from the measured one for local enhancement only. The result shows △CO and △NO2 are highly correlated (R > 0.7 and 0.6, respectively) with △CO2 at the same time. Coefficient of correlation between △CO2 and △PM2.5 continues to increase and has a maximum correlation (R > 0.3) after 3 hours when the time of △CO2 is fixed. This is thought to be a delay for production of PM2.5 by the primary particulate matter emitted with CO2. Also, the ratio of △pollutant to △CO2 represents the air pollutants emitted by the fuel consumed, which can be used to guess emission characteristics of Seoul by comparing it with previous studies. The △CO:△CO2 (6 ppbppm-1) is slightly lower compared to ground-level value in Utah (7.38 ppb ppm-1) and KORUS-AQ airborne one in Seoul (9.09 ppb ppm-1). And the △NO2:△CO2 (0.37 ppb ppm-1) is significantly lower in Seoul compared to tunnel traffic emission value in Paris (3.32 ppb ppm-1), but △PM2.5:△CO2 (0.19 μgm-3ppm-1) is similar with the ratio in Utah (0.18 μgm-3

ppm-1). Because we focus on the city scale and the measurement points of CO2 and air pollutants are different, ratios of this study can be lower than ones of previous studies, but result is still meaningful. Our results suggest that monitoring urban CO2 can serve as an internal indicator of urban air pollutants.

T38


Carbon Dioxide Enhancement over Seoul Capital Area from Space and Surface Measurements

Chaerin Park1, Su-Jong Jeong1


Assessment of urban carbon emission is a critical issue to understand the global carbon cycle. In this research, we evaluate the spatial and temporal variations in atmospheric carbon dioxide concentrations over the Seoul Capital Area, where is one of apparent Megacities across the world. This study analyzed urban CO2 variations using column integrated XCO2 from Orbiting Carbon Observatory from 2014 to 2018 and ground-based measurements over Seoul capital area. Results show that Seoul has higher values of carbon dioxide concentration than its neighbor background value. From XCO2, Seoul’s carbon dioxide concentration is increasing from 398.62 ppm to 409.23 ppm during the research period. XCO2 concentration of Seoul is 1.39 ppm to 2.85 ppm higher compared to the nearby background area of Mt. Jiri. A comparison of ground-based CO2 concentrations between Seoul and Anmyeond-do (GAW site) shows that concentrations in Seoul is on average 31.06 ppm higher than that of Anmyeond-do. More details in our study will be presented in the workshop. Our Carbon dioxide anomaly statistics and distribution of Seoul can provide valuable insight for comprehending carbon dioxide emissions over the megacity across the world.

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High precision CO2 measurement at Beijing-Tianjin-Hebei city cluster in China

Bo Yao1, Ying Duan2, Lin Wu3, Ting Wang3, Wanqi Sun1, Xiaobo Dong2, Guoming Wu4

1. Meteorological Observation Center of China Meteorological Administration 2. Weather Modification Office of Hebei Province 3. Institute of Atmospheric Physics, Chinese Academy of Sciences 4. Hebei Institute of Meteorological Sciences

Carbon dioxide (CO2) is the most important greenhouse gas. Urban areas are responsible for 70% of CO2 emissions, so it is important to identify carbon sources and their emission strengths on urban scale. China is the largest developing county with the biggest CO2 anthropogenic emission in the world. However, integrated CO2 observation at city scale has not been reported in China. Supported by China National Key R&D project, observation systems based on CRDS high precision CO2 monitor and automatic calibration system have been established at six core stations in Beijing-Tianjin-Hebei city cluster. The measurement at the six stations shared the same technique, adopt the same calibration process and all the results were traced to the World Meteorological Organization (WMO) calibration scale. Moreover, two airplanes were modified to observe CO2 concentrations from near surface to 5400 m at Shijiazhuang and Tangshan. CO2 concentration in Beijing, and Shijiazhuang with fine resolution have been obtained by mobile vehicle equipped with CRDS system. The integrated observation of atmospheric CO2 was carried out by multiple research platforms in September 2018 and January 2019, aiming to quantify CO2 emission of Shijiazhuang by different methods.

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High precision CO2 measurement at Beijing-Tianjin-Hebei city cluster in China

Bo Yao1, Ying Duan2, Lin Wu3, Ting Wang3, Wanqi Sun1, Xiaobo Dong2, Guoming Wu4

1. Meteorological Observation Center of China Meteorological Administration 2. Weather Modification Office of Hebei Province 3. Institute of Atmospheric Physics, Chinese Academy of Sciences 4. Hebei Institute of Meteorological Sciences

Carbon dioxide (CO2) is the most important greenhouse gas. Urban areas are responsible for 70% of CO2 emissions, so it is important to identify carbon sources and their emission strengths on urban scale. China is the largest developing county with the biggest CO2 anthropogenic emission in the world. However, integrated CO2 observation at city scale has not been reported in China. Supported by China National Key R&D project, observation systems based on CRDS high precision CO2 monitor and automatic calibration system have been established at six core stations in Beijing-Tianjin-Hebei city cluster. The measurement at the six stations shared the same technique, adopt the same calibration process and all the results were traced to the World Meteorological Organization (WMO) calibration scale. Moreover, two airplanes were modified to observe CO2 concentrations from near surface to 5400 m at Shijiazhuang and Tangshan. CO2 concentration in Beijing, and Shijiazhuang with fine resolution have been obtained by mobile vehicle equipped with CRDS system. The integrated observation of atmospheric CO2 was carried out by multiple research platforms in September 2018 and January 2019, aiming to quantify CO2 emission of Shijiazhuang by different methods.

T40


Updates from the Los Angeles Megacities Carbon Project Jooil Kim1, Kristal Verhulst2, Anna Karion3, Peter Salameh1, Vineet Yadav2, Francesca Hopkins4, Ray Weiss1, Ralph Keeling1, Riley Duren2, Charles Miller2, Matthias Falk5, William Callahan6, Michael Stock6, Steve Prinzivalli6, James Whetstone3 1. Scripps Institution of Oceanography, University of California San Diego 2. NASA Jet Propulsion Laboratory, California Institute of Technology 3. National Institute of Standards and Technology 4. University of California Riverside 5. California Air Resources Board 6. Earth Networks, Inc.

Emissions from cities make up a dominant portion of the total greenhouse gas (GHG) emissions from human activities, and the importance of these emissions is expected to grow as urbanization trends continue around the world. As policies to quantify and reduce GHG emissions are explored and adopted at the city level, urban measurements of GHGs can help guide effective strategies and gauge success of these efforts. The Los Angeles Megacities Carbon Project (LA Megacities) is one of three urban testbeds established by the US National Institute of Standards and Technology (NIST), and is an academic, governmental and business partnership. Its current in situ measurement network of cavity ring-down spectrometer instruments consists of 7 Picarro model G2401s (measuring CO2, CH4 and CO), 3 Picarro model G2301s paired with model G5310s (measuring CO2, CH4 and CO and N2O, respectively), and 2 Picarro model G2301s (measuring CO2 and CH4). All instruments use Nafion for partial drying, are operated under custom operational protocols, and use GCWerks software for automation and data processing. We present here the current status of the measurement network and an overview of recent and ongoing contributions. Topics to be covered include general network performance and uncertainty metrics, analysis of calibration scale propagation, and early results from applying machine learning techniques to the measurement data.

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Development of A Full Carbon Budget for Auckland, New Zealand

Jocelyn Turnbull1, Elizabeth Keller1, Jeremy Thompson1, Julia Collins1, Sara Mikaloff Fletcher2, Gordon Brailsford2, Shanju Xie3, Nancy Golubiewski3, Kevin Gurney4, Lucy Hutyra5

1. GNS Science 2. NIWA 3. Auckland Council 4. Northern Arizona University 5. Boston University

City governments are often leading the way in CO2 emission mitigation efforts, both to address the climate challenge and the many associated co-benefits. Cities want to assess the potential of carbon mitigation strategies and planning decisions as well as evaluate the success of such strategies. Currently, cities estimate their emissions using one of several available city-scale protocols, loosely based on national inventory reporting methods. Getting these city-scale inventories right is challenging, and typically provide only whole city total fluxes. Critically, no reliable estimates of urban land carbon exchange are available. The recent expansion of urban greenhouse gas research means that we now have the tools to provide more detailed information. We are working with Auckland Council, the New Zealand Government’s Ministry for the Environment and local indigenous groups to develop scientifically robust urban greenhouse gas information that is useful and relevant to these stakeholders. This work forms part of CarbonWatch-NZ, which aims to provide detailed greenhouse gas flux information for all of New Zealand. We have collected flask samples from ~30 sites around Auckland in eight campaigns over the last two years. We determine the enhancements in CO2, CO, CH4 and fossil fuel CO2 (CO2_ff, derived from 14CO2) relative to incoming clean air upwind of the city. In tandem, we have developed bottom-up flux models for both CO2_ff and biogenic CO2 exchange (CO2_bio) for Auckland. In 2019, we will expand the program to include three long-term sites measuring in situ CO2, CO and CH4 along with weekly flask samples for a suite of species, and implementing a regional scale atmospheric inversion system for Auckland. We will present results from the pilot project, demonstrating that Auckland has no dormant season, and the biosphere is active year-round with little apparent seasonality. Initial results suggest that Auckland’s biogenic flux is a modest net sink. Our observations of CO: CO2_ff ratios are consistent with traffic being the dominant CO2_ff source in Auckland.

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Development of A Full Carbon Budget for Auckland, New Zealand

Jocelyn Turnbull1, Elizabeth Keller1, Jeremy Thompson1, Julia Collins1, Sara Mikaloff Fletcher2, Gordon Brailsford2, Shanju Xie3, Nancy Golubiewski3, Kevin Gurney4, Lucy Hutyra5

1. GNS Science 2. NIWA 3. Auckland Council 4. Northern Arizona University 5. Boston University

City governments are often leading the way in CO2 emission mitigation efforts, both to address the climate challenge and the many associated co-benefits. Cities want to assess the potential of carbon mitigation strategies and planning decisions as well as evaluate the success of such strategies. Currently, cities estimate their emissions using one of several available city-scale protocols, loosely based on national inventory reporting methods. Getting these city-scale inventories right is challenging, and typically provide only whole city total fluxes. Critically, no reliable estimates of urban land carbon exchange are available. The recent expansion of urban greenhouse gas research means that we now have the tools to provide more detailed information. We are working with Auckland Council, the New Zealand Government’s Ministry for the Environment and local indigenous groups to develop scientifically robust urban greenhouse gas information that is useful and relevant to these stakeholders. This work forms part of CarbonWatch-NZ, which aims to provide detailed greenhouse gas flux information for all of New Zealand. We have collected flask samples from ~30 sites around Auckland in eight campaigns over the last two years. We determine the enhancements in CO2, CO, CH4 and fossil fuel CO2 (CO2_ff, derived from 14CO2) relative to incoming clean air upwind of the city. In tandem, we have developed bottom-up flux models for both CO2_ff and biogenic CO2 exchange (CO2_bio) for Auckland. In 2019, we will expand the program to include three long-term sites measuring in situ CO2, CO and CH4 along with weekly flask samples for a suite of species, and implementing a regional scale atmospheric inversion system for Auckland. We will present results from the pilot project, demonstrating that Auckland has no dormant season, and the biosphere is active year-round with little apparent seasonality. Initial results suggest that Auckland’s biogenic flux is a modest net sink. Our observations of CO: CO2_ff ratios are consistent with traffic being the dominant CO2_ff source in Auckland.

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Progress from the Indianapolis Flux (INFLUX) tower-based urban greenhouse gas network Natasha Miles1, Nikolay Balashov2, Kenneth Davis1, Thomas Lauvaux3, Vanessa Monteiro1, Scott Richardson1, Kai Wu1 1. Penn State University 2. NASA/GSFC 3. LSCE

The overall objective of the Indianapolis Flux Experiment (INFLUX) is to develop, evaluate and improve methods for measuring greenhouse gas emissions from cities. Tower-based measurements are one aspect of the INFLUX project. Cavity ring-down spectroscopic tower-based measurements of CO2, CH4, and CO mole fractions began in Indianapolis in 2010, and have been used in conjunction with a Bayesian inversion to estimate urban greenhouse gas emissions. Additionally, fluxes have thus been directly measured via eddy covariance at a suburban tower (with anthropogenic carbon emissions as well as urban forest and grass fluxes), and at corn, soy, and grass sites in and around the city. We present progress to address various challenges for the atmospheric determination of greenhouse gas emissions. First we describe complexities of the background for urban CO2 and CH4 measured in Indianapolis. We also present updated results using standard deviation of CO2 as an indicator of point source emission strength, a method which requires no background. We then discuss flux tower measurements of urban grass, indicating significant photosynthesis even during the dormant season when vegetation models predict no net carbon uptake. Finally, we explore conditions conducive to the use of nocturnal data in inversions of urban carbon emissions.

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Greenhouse gas observations from the Northeast Corridor tower network

Anna Karion1, William Callahan2, Michael Stock2, Steve Prinzivalli2, Kristal Verhulst3, Jooil Kim4, Peter Salameh5, Israel Lopez-Coto1, James Whetstone1

1. NIST 2. Earth Networks, Inc. 3. Caltech / NASA JPL 4. Scripps Institution of Oceanography 5. GC Werks, Inc.

As the population of cities grows globally due to trends toward urbanization, so does their relative contribution to global anthropogenic greenhouse gas (GHG) budgets. Increasingly, individual city and regional governments are making pledges to achieve ambitious GHG reduction targets. Atmospheric measurements provide additional useful information to such efforts, by confirming inventory estimates, detecting trends, or estimating emissions that are not well quantified using inventory methods, such as methane and other non-CO2 emissions. The National Institute of Standards and Technology (NIST) has partnered with other federal, private, and academic institutions to establish three urban testbeds in the United States: the Indianapolis Flux Experiment (INFLUX, influx.psu.edu), the Los Angeles Megacities Carbon Project (megacities.jpl.nasa.gov), and the Northeast Corridor (NEC, www.nist.gov/topics/northeast-corridor-urban-test-bed). The goals of the urban testbeds are to develop and refine techniques for estimating greenhouse gas emissions from cities and to understand the uncertainty of emissions estimates at various spatial and temporal scales. The Northeast Corridor (NEC) was established in 2015 as the third NIST urban testbed. The goals for this project are to demonstrate that top-down atmospheric emissions estimation methods can be used in a domain that is complicated by many upwind and nearby emissions sources in the form of surrounding urban areas. The objective is to isolate the anthropogenic GHG emissions from urban areas along the U.S. East Coast from many confounding sources upwind (cities, oil and gas development, coal mines, and powerplants) and from the large biological CO2 signal from the highly productive agricultural areas and forests nearby and within the cities. The NEC project has a current focus on the urban areas of Washington, D.C. and Baltimore, Maryland, U.S.A., with existing plans to expand northward to cover the entire urbanized corridor of the Northeast U.S. The NEC project includes multiple measurement and analysis components. The backbone of the NEC project is a network of in-situ CO2 and CH4 observation stations with continuous high-accuracy mole fraction measurements of these two greenhouse gases. In addition, periodic flight campaigns of multiple weeks each year are conducted by the University of Maryland and Purdue University, focusing on wintertime observations of CO2, CH4, and CO from instrumented aircraft. The NEC project also includes an extensive modelling component, using high-resolution meteorological model output coupled to Lagrangian dispersion models to interpret observations from both aircraft and tower

75

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Greenhouse gas observations from the Northeast Corridor tower network

Anna Karion1, William Callahan2, Michael Stock2, Steve Prinzivalli2, Kristal Verhulst3, Jooil Kim4, Peter Salameh5, Israel Lopez-Coto1, James Whetstone1

1. NIST 2. Earth Networks, Inc. 3. Caltech / NASA JPL 4. Scripps Institution of Oceanography 5. GC Werks, Inc.

As the population of cities grows globally due to trends toward urbanization, so does their relative contribution to global anthropogenic greenhouse gas (GHG) budgets. Increasingly, individual city and regional governments are making pledges to achieve ambitious GHG reduction targets. Atmospheric measurements provide additional useful information to such efforts, by confirming inventory estimates, detecting trends, or estimating emissions that are not well quantified using inventory methods, such as methane and other non-CO2 emissions. The National Institute of Standards and Technology (NIST) has partnered with other federal, private, and academic institutions to establish three urban testbeds in the United States: the Indianapolis Flux Experiment (INFLUX, influx.psu.edu), the Los Angeles Megacities Carbon Project (megacities.jpl.nasa.gov), and the Northeast Corridor (NEC, www.nist.gov/topics/northeast-corridor-urban-test-bed). The goals of the urban testbeds are to develop and refine techniques for estimating greenhouse gas emissions from cities and to understand the uncertainty of emissions estimates at various spatial and temporal scales. The Northeast Corridor (NEC) was established in 2015 as the third NIST urban testbed. The goals for this project are to demonstrate that top-down atmospheric emissions estimation methods can be used in a domain that is complicated by many upwind and nearby emissions sources in the form of surrounding urban areas. The objective is to isolate the anthropogenic GHG emissions from urban areas along the U.S. East Coast from many confounding sources upwind (cities, oil and gas development, coal mines, and powerplants) and from the large biological CO2 signal from the highly productive agricultural areas and forests nearby and within the cities. The NEC project has a current focus on the urban areas of Washington, D.C. and Baltimore, Maryland, U.S.A., with existing plans to expand northward to cover the entire urbanized corridor of the Northeast U.S. The NEC project includes multiple measurement and analysis components. The backbone of the NEC project is a network of in-situ CO2 and CH4 observation stations with continuous high-accuracy mole fraction measurements of these two greenhouse gases. In addition, periodic flight campaigns of multiple weeks each year are conducted by the University of Maryland and Purdue University, focusing on wintertime observations of CO2, CH4, and CO from instrumented aircraft. The NEC project also includes an extensive modelling component, using high-resolution meteorological model output coupled to Lagrangian dispersion models to interpret observations from both aircraft and tower

T43


stations and in atmospheric inverse analyses to estimate fluxes of CO2 and CH4 from the cities of Washington, D.C. and Baltimore, Maryland. In this presentation we will focus on the high-accuracy tower observation network and associated data collection and processing methods. We will describe the tower network design and characterize the different site locations; describe the measurement methods, instrumentation, and calibration; and present the uncertainty derivation for the tower network measurements. Finally, we will present some observations from the current record and the status of current modelling efforts.

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Long-term monitoring and modelling of atmospheric CH4 to track its trend and to assess a detailed spatially explicit emission mapin the Greater Toronto and Hamilton Area, Canada Felix Vogel1, Sebastien Ars2, Nasrin Pak2, Debra Wunch2, Junhua Zhang1, Mike Moran1, Elton Chan1, Doug Worthy1 1. Environment and Climate Change Canada 2. University of Toronto

Today, cities and metropolitan areas account for ca. 70% of energy-related Greenhouse Gas (GHG) emissions globally and their share is predicted to become even more important in the future [IPCC, 2014]. Understanding processes contributing to emissions and tracking the impact of interventions will be critical if companies and city stakeholders want to cost-efficiently reduce GHG emissions under their control. Among the gases emitted due to human activities and infrastructure, methane (CH4) plays an important role as it is both a short-lived climate pollutant affecting air quality as well as being the second-most important anthropogenic GHG. There are also ‘no-regret’ mitigation options for CH4, as emissions are often fugitive (i.e., unintended) and can be reduced without significant costs, in contrast to combustion-related emissions of CO2. Within the framework of a demonstration experiment in the Greater Toronto and Hamilton Area (GTHA) in Canada that is contributing to the Integrated Global GHG information system of WMO/UNEP, multiple data streams are being combined to try to find additional mitigation potentials and track long-term trends. Here, we present the results of our atmospheric observations of CH4 and other GHGs and short-lived climate pollutants conducted in the GTHA by Environment and Climate Change Canada (ECCC) over the past decade. Long-term trends in atmospheric CH4 indicate that the concentration difference within the dense urban center and its outskirts has significantly changed since measurements began. GHG fluxes are also quantified using the Radon tracer method (Levin et al. 1999) and compared to reported emissions in the region. To date three spatialized emission products exist for the GTHA developed by the University of Toronto, the Air Quality Research Division of ECCC, and the Joint Research Centre of the European commission (which provides the global EDGAR emission product). Using Lagrangian transport modelling the CH4 concentrations predicted at our measurement stations are compared to our long-term observations to assess if these observations are able to discriminate between the three, quite different, emissions datasets. Besides these fixed site observations, we have also been conducting regular mobile measurement campaigns in the GTHA since summer 2018, and first results on typical enhancements as well as hot-spot frequencies, and their implications, will be discussed.

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Long-term monitoring and modelling of atmospheric CH4 to track its trend and to assess a detailed spatially explicit emission mapin the Greater Toronto and Hamilton Area, Canada Felix Vogel1, Sebastien Ars2, Nasrin Pak2, Debra Wunch2, Junhua Zhang1, Mike Moran1, Elton Chan1, Doug Worthy1 1. Environment and Climate Change Canada 2. University of Toronto

Today, cities and metropolitan areas account for ca. 70% of energy-related Greenhouse Gas (GHG) emissions globally and their share is predicted to become even more important in the future [IPCC, 2014]. Understanding processes contributing to emissions and tracking the impact of interventions will be critical if companies and city stakeholders want to cost-efficiently reduce GHG emissions under their control. Among the gases emitted due to human activities and infrastructure, methane (CH4) plays an important role as it is both a short-lived climate pollutant affecting air quality as well as being the second-most important anthropogenic GHG. There are also ‘no-regret’ mitigation options for CH4, as emissions are often fugitive (i.e., unintended) and can be reduced without significant costs, in contrast to combustion-related emissions of CO2. Within the framework of a demonstration experiment in the Greater Toronto and Hamilton Area (GTHA) in Canada that is contributing to the Integrated Global GHG information system of WMO/UNEP, multiple data streams are being combined to try to find additional mitigation potentials and track long-term trends. Here, we present the results of our atmospheric observations of CH4 and other GHGs and short-lived climate pollutants conducted in the GTHA by Environment and Climate Change Canada (ECCC) over the past decade. Long-term trends in atmospheric CH4 indicate that the concentration difference within the dense urban center and its outskirts has significantly changed since measurements began. GHG fluxes are also quantified using the Radon tracer method (Levin et al. 1999) and compared to reported emissions in the region. To date three spatialized emission products exist for the GTHA developed by the University of Toronto, the Air Quality Research Division of ECCC, and the Joint Research Centre of the European commission (which provides the global EDGAR emission product). Using Lagrangian transport modelling the CH4 concentrations predicted at our measurement stations are compared to our long-term observations to assess if these observations are able to discriminate between the three, quite different, emissions datasets. Besides these fixed site observations, we have also been conducting regular mobile measurement campaigns in the GTHA since summer 2018, and first results on typical enhancements as well as hot-spot frequencies, and their implications, will be discussed.

T45


Comparisons of AirCore vertical profiles of greenhouse gases from an intensive RINGO campaign at Sodankylä, Finland Huilin Chen1, Joram Hooghiem1, Rebecca Brownlow1, Rigel Kivi2, Pauli Heikkinen2, Markus Leuenberger3, Peter Nyfeler3, Michel Ramonet4, Morgan Lopez4, Andreas Engel5, Thomas Wagenhaeuser5, Johannes Laube6, Bianca Baier7, Colm Sweeney8, Francois Danis9, Cyril Crevoisier9 1. Centre for Isotope Research, University of Groningen, The Netherlands 2. Finnish Meteorological Institute, Sodankylä, Finland 3. Physics Institute, University of Bern, Switzerland 4. Laboratoire des Sciences du Climat et de l’Environnement (LSCE/IPSL), Université Paris Saclay CEA-CNRS-UVSQ, Gif-sur-Yvette, France 5. Institute for Atmospheric and Environmental Sciences, Goethe University of Frankfurt, Frankfurt, Germany 6. School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich, UK 7. Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, USA 8. National Oceanic and Atmospheric Administration, Earth System Research Laboratory, NOAA/ESRL, Boulder, Colorado, USA 9. Laboratoire de Météorologie Dynamique, CNRS, IPSL, Ecole Polytechnique, Palaiseau, France

Within the EU-funded Readiness of Integrated carbon observation system (ICOS) for Necessities of integrated Global Observations (RINGO) project, vertical profile measurements have been explored using both AirCores and the ground-based Total Carbon Column Observing Network (TCCON) Fourier-transform infrared spectrometers (FTIRs) to enhance the link between ICOS ground-based stations, TCCON, and satellite measurements. AirCore is a long coiled stainless-steel tube used for atmospheric sampling up to heights of around 30 km, which is launched on a weather balloon with one end open and the other end closed, and collects a continuous ambient air sample during descent. The analysis results of the air samples for greenhouse and other trace gas mole fractions combined with the recorded in-flight information, e.g. coil temperatures, ambient pressure and altitude, allow for the altitude registration of measurements for constructing vertical profiles. In June 2018, an intensive AirCore comparison campaign took place at the TCCON site in Sodankylä, Finland. A total of 10 balloon flights and 26 vertical profiles were made, with combinations of different AirCores and/or the Lightweight Stratospheric Air (LISA) sampler per balloon flight. The measured species include CO2, CH4, CO, O2, H2O by continuous cavity ring-down spectrometers (CRDS) at Sodankylä, and subsequent isotopic compositions of CO2, CH4 and halogenated trace gases by delayed analyses of collected stratospheric air samples conducted later in several individual home laboratories. Here we present the results from this campaign and compare different AirCore/LISA profiles to show 1) the accuracy of CO2 and CO mole fractions measured in AirCores; 2) the accuracy of the altitude registration of AirCore measurements; 3) a comparison of AirCore observations with and without drying the air sample; 4) the influence of different tubing surfaces on the accuracy of tracegas measurements.

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Continuous airborne measurements of CO2, CH4, H2O and CO in South Korea Shanlan Li1, Tae-Young Goo1, Samuel Takele Kenea1, Lev Labzovskii1, Young-Suk Oh1, Young-Hwa Byun1 1. National Institute of Meteorological Sciences

A new Korean Meteorological Administration (KMA) airborne measurement platform has been established for regular observations with scientific purpose over South Korea since 2018. CRDS analyzer mounted on the King Air 350HW was used to measure in-situ CO2, CH4, CO and H2O maxing ratios. The total uncertainty of airborne measurements was estimated to be 0.22 ppm for CO2, 3.6 ppb for CH4, and 4.3 ppb for CO by combination of NOAA whole-air accuracy, instrument precision, and water vapor correction uncertainty. The airborne vertical profile measurements were performed at a regional GWA Anmyeon-do (AMY) station that belongs to the Total Carbon Column Observing Network (TCCON) and provides concurrent observations to the Greenhouse Gases Observing Satellite (GOSAT) overpasses. Also, the lower altitude survey was conducted from the north to the south of Korea to detect the carbon plume along the region, the populated by the urban and agriculture emissions. The spatial distributions of greenhouse gases over Korea show the clear latitudinal and vertical gradient. The 1.5-8.0 km vertically averaged CO2 mixing ratios are comparable with background surface values at AMY and Ryori station but CH4 mixing ratio shows lower level than those from ground GWA stations, comparable with flask airborne data taken in the western pacific region. Furthermore, this study shows that the combination of CH4 distribution in free troposphere and trajectory analysis, taking account of convective mixing, is a useful tool in investigating CH4 transport processes.

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Continuous airborne measurements of CO2, CH4, H2O and CO in South Korea Shanlan Li1, Tae-Young Goo1, Samuel Takele Kenea1, Lev Labzovskii1, Young-Suk Oh1, Young-Hwa Byun1 1. National Institute of Meteorological Sciences

A new Korean Meteorological Administration (KMA) airborne measurement platform has been established for regular observations with scientific purpose over South Korea since 2018. CRDS analyzer mounted on the King Air 350HW was used to measure in-situ CO2, CH4, CO and H2O maxing ratios. The total uncertainty of airborne measurements was estimated to be 0.22 ppm for CO2, 3.6 ppb for CH4, and 4.3 ppb for CO by combination of NOAA whole-air accuracy, instrument precision, and water vapor correction uncertainty. The airborne vertical profile measurements were performed at a regional GWA Anmyeon-do (AMY) station that belongs to the Total Carbon Column Observing Network (TCCON) and provides concurrent observations to the Greenhouse Gases Observing Satellite (GOSAT) overpasses. Also, the lower altitude survey was conducted from the north to the south of Korea to detect the carbon plume along the region, the populated by the urban and agriculture emissions. The spatial distributions of greenhouse gases over Korea show the clear latitudinal and vertical gradient. The 1.5-8.0 km vertically averaged CO2 mixing ratios are comparable with background surface values at AMY and Ryori station but CH4 mixing ratio shows lower level than those from ground GWA stations, comparable with flask airborne data taken in the western pacific region. Furthermore, this study shows that the combination of CH4 distribution in free troposphere and trajectory analysis, taking account of convective mixing, is a useful tool in investigating CH4 transport processes.

T47


Light Rail-Based Monitoring of Greenhouse Gases Across An Urban Area

Edward Orr1, Logan Mitchell2, Ben Fasoli2, John Lin2, Frédéric Despagne1

1. ABB Inc. 2. University of Utah

Anthropogenic emissions within urban environments are characterized by spatial heterogeneity and temporal variability that present challenges for measuring urban greenhouse gases and air pollutants. To address these challenges, several instruments were mounted on public transit light-rail train cars that traverse the metropolitan Salt Lake Valley in Utah, USA to observe the temporal and spatial variability of several atmospheric species. Utilizing electrified light-rail public transit as an observational platform enables real-time measurements with low operating costs while avoiding self-contamination from vehicle exhaust. Off-axis integrated cavity output spectroscopy (OA-ICOS) laser-based analyzers were used for the real-time measurements of CO2, CH4 and NO2. The examination of temporal averages and case studies of each species reveal gradients, intermittent point sources, seasonal and diel changes, and complex relationships resulting from emissions, atmospheric chemistry, and meteorological conditions. The ongoing multi-year record of spatial and temporal air quality observations provides a valuable data set for future air quality exposure studies. The results suggest pollution and greenhouse gas emission monitoring and exposure assessment could be greatly enhanced by deploying instruments on public transit systems in urban centers worldwide.

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Mobile real-time measurement of methane in Beijing: methodology development and application

Wanqi Sun1, Bo Yao1

1. CMA Meteorologlcal Observation Centre

A fuel switching policy, converting coal to natural gas, has been put into effect across China in recent years. Fugitive emissions associated with this switch may greatly influence emissions of the whole city. A mobile platform observation of car, consisting of a power supply, an instrument, a GPS receiver and a data acquisition device, was set up and used to online monitor the atmosphere CH4 in Beijing. The observation result shows that: the CH4 concentration distribution of the urban is uniform; that of the rural-urban fringe is obvious influenced by the wind; that of the rural is mainly influenced by point sources. Meanwhile, some fugitive emission source, such as LNG the running power plant and leaking natural gas pipeline, were identified in the rural measurement. The CH4 emission comparison for heating and un-heating period shows that the methane leakage from municipal facilities is probably greatly contributed to the whole emission of the city. This methodology has enough temporal and spatial resolution to survey point and non-point sources of methane and the in urban and this observation is probably greatly help to understand the whole emission of the city.

81

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Mobile real-time measurement of methane in Beijing: methodology development and application

Wanqi Sun1, Bo Yao1

1. CMA Meteorologlcal Observation Centre

A fuel switching policy, converting coal to natural gas, has been put into effect across China in recent years. Fugitive emissions associated with this switch may greatly influence emissions of the whole city. A mobile platform observation of car, consisting of a power supply, an instrument, a GPS receiver and a data acquisition device, was set up and used to online monitor the atmosphere CH4 in Beijing. The observation result shows that: the CH4 concentration distribution of the urban is uniform; that of the rural-urban fringe is obvious influenced by the wind; that of the rural is mainly influenced by point sources. Meanwhile, some fugitive emission source, such as LNG the running power plant and leaking natural gas pipeline, were identified in the rural measurement. The CH4 emission comparison for heating and un-heating period shows that the methane leakage from municipal facilities is probably greatly contributed to the whole emission of the city. This methodology has enough temporal and spatial resolution to survey point and non-point sources of methane and the in urban and this observation is probably greatly help to understand the whole emission of the city.

T49


Statistical characterization of atmospheric CO2 in airport proximity from the CONTRAIL commercial aircraft measurements

Taku Umezawa1, Hidekazu Matsueda2, Yousuke Sawa3, Toshinobu Machida1, Yosuke Niwa1, Kaz Higuchi4, Tomohiro Oda5, Shamil Maksyutov1

1. National Institute for Environmental Studies, Tsukuba, Japan 2. Meteorological Research Institute, Tsukuba, Japan 3. Japan Meteorological Agency, Tokyo, Japan 4. York University, Toronto, Canada 5. NASA Goddard Space Flight Center, Greenbelt, USA

Urban CO2 emissions estimated from vertical atmospheric measurements can contribute to an independent verification of the reporting of national emissions and will have political implications. We analyzed atmospheric CO2 mole fraction data obtained onboard commercial aircraft in proximity to 36 airports worldwide, as part of Comprehensive Observation Network for Trace gases by Airliners (CONTRAIL). At many airports, we observed significant flight-to-flight variations of CO2 mole fraction enhancements downwind of neighboring cities, providing advective footprints of CO2 emissions from various cities. Observed CO2 variability increased with decreasing altitude, magnitude of which varied from city to city. We found that the magnitude of CO2 variability near the ground (~1 km altitude) at an airport was correlated with the intensity of CO2 emissions from a nearby city. Our study has demonstrated the utility of commercial aircraft data for city-scale anthropogenic CO2 emission studies.

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Implementing Atmospheric CO2 Measurements from Ships of Opportunity

Rik Wanninkhof1, David Munro2, Colm Sweeney3, Denis Pierrot4, Kevin Sullivan4

1. NOAA/AOML 2. CIRES/U.Colorado 3. NOAA/ESRL/GMD 4. CIMAS/U. Miami

Primary goals of the nascent Surface Ocean CO2 NETwork (SOCONET) and ongoing atmospheric Marine Boundary Layer (MBL) CO2 measurements from ships and buoys are to provide accurate surface ocean pCO2 and atmospheric xCO2 data to within 2 micro atmosphere (µatm) and 0.2 parts per million (ppm), respectively, following rigorous best practices, calibration and inter-comparison procedures. Attaining these targets will improve estimates of air-sea CO2 fluxes, and partitioning of carbon fluxes between terrestrial and coastal oceans through inverse modeling. In particular, the effects of continental airflow on MBL CO2 are not included in the widely-used NOAA MBL data product, potentially leading to biased air-sea CO2 flux estimates over coastal waters. Over the last year, NOAA/ESRL/GMD and AOML have begun a collaboration through the Ship of Opportunity (SOOP)-CO2 program to evaluate and improve the atmospheric measurement repeatability from SOOP-CO2 ships with the goal of demonstrating that measurements from underway pCO2 systems used for surface water measurements can consistently meet these targets. Here, we show initial results that demonstrate that accurate atmospheric CO2 measurements compatible to within ±0.2 ppm of the global CO2 scale maintained by the WMO/GAW Central Calibration Laboratory (CCL) are feasible from underway pCO2 systems. Methodologies needed to reach this compatibility level are presented.

T50


Implementing Atmospheric CO2 Measurements from Ships of Opportunity

Rik Wanninkhof1, David Munro2, Colm Sweeney3, Denis Pierrot4, Kevin Sullivan4

1. NOAA/AOML 2. CIRES/U.Colorado 3. NOAA/ESRL/GMD 4. CIMAS/U. Miami

Primary goals of the nascent Surface Ocean CO2 NETwork (SOCONET) and ongoing atmospheric Marine Boundary Layer (MBL) CO2 measurements from ships and buoys are to provide accurate surface ocean pCO2 and atmospheric xCO2 data to within 2 micro atmosphere (µatm) and 0.2 parts per million (ppm), respectively, following rigorous best practices, calibration and inter-comparison procedures. Attaining these targets will improve estimates of air-sea CO2 fluxes, and partitioning of carbon fluxes between terrestrial and coastal oceans through inverse modeling. In particular, the effects of continental airflow on MBL CO2 are not included in the widely-used NOAA MBL data product, potentially leading to biased air-sea CO2 flux estimates over coastal waters. Over the last year, NOAA/ESRL/GMD and AOML have begun a collaboration through the Ship of Opportunity (SOOP)-CO2 program to evaluate and improve the atmospheric measurement repeatability from SOOP-CO2 ships with the goal of demonstrating that measurements from underway pCO2 systems used for surface water measurements can consistently meet these targets. Here, we show initial results that demonstrate that accurate atmospheric CO2 measurements compatible to within ±0.2 ppm of the global CO2 scale maintained by the WMO/GAW Central Calibration Laboratory (CCL) are feasible from underway pCO2 systems. Methodologies needed to reach this compatibility level are presented.


Poster Session

85

P1


The inter-comparison activities of WCC-SF6 during 8 years

Haeyoung Lee1, Sepyo Lee1, Sang-Sam Lee1, Sang-Boom Ryoo1

1. KMA/NIMS

WMO/GAW Programme encouraged World Calibration Centres (WCCs) to help improve data quality, homogenize data from different stations and networks. The Korea Meteorological Administration (KMA) has played a role as the WCC for SF6 (WCC-SF6) since 2012 under the MoU with the WMO. To implement those activities, it is very important to keep the traceability and compatibility between Central Calibration Laboratory (CCL). Also to maintain data quality and homogenized data in and between stations, inter-comparison experiment is valuable under the GAW Program. WCC-SF6 has implemented inter-comparison experiments with CCL biennially since 2013 and first international comparison campaign with 12 labs in Europe and Asia-Pacific Countries from 2016 to 2017. So far we have conducted the audit at three major stations in GAW with our travelling cylinders to see the linearity and differences between WCC and stations. Here we would like to show the results from those activities and suggest what makes big differences in measurement as reviewing last 8 years inter comparison activities.

86

P2


Travelling cylinders as a quality control tool in ICOS atmospheric station network

Hermanni Aaltonen1, Juha Hatakka1, Michel Ramonet2, Daniel Rzesanke3, Tuomas Laurila1

1. Finnish Meteorological Institute 2. Laboratoire des Sciences du Climat et de l’Environnement 3. Max-Planck-Institute for Biogeochemistry

The quality control (QC) of European-wide ICOS atmospheric station (AS) network is implemented by several levels and methods from regular leak tests at stations via integrated data checking algorithms to station audits. Travelling QC cylinders is a method having already a long history in measurement networks, like “Round Robins” in GAW stations and “Cucumbers” in CarboEurope. The travelling cylinders approach is tested also in ICOS ASs; do these cylinders give additional value for QC that is not otherwise achieved and is the amount of additional work required in line with the QC benefits? The role of separate QC cylinders in ICOS AS network differs from most of the other measurement networks, since all the ASs are using calibration gases centrally prepared in ICOS Central Analytical Laboratory (CAL). When the calibration gases are consistent, the role of travelling QC cylinders is more like to evaluate the performance and expertise of AS and its personnel than to intercompare the gas concentration levels due to inconsistent calibration cylinders. Naturally, travelling cylinders provide also a tool to follow the stability and possible quality problems of calibration gases in AS network. The instrumentation for greenhouse gas measurements in ICOS ASs is rather uniform due to strict demands for measurement precision. Also each individual instrument is tested before the approval for ICOS AS use. However, instrument’s performance may decline by age, which is very difficult to observe from ambient air measurements only. With calibration gases the picture is basically the same. Gas concentrations inside the cylinder may drift by age, and as the lifetime of a calibration gas cylinder is several years, the drift is difficult to observe before the recalibration at CAL in the end of its lifetime. Routine QC tool for the performance of ICOS ASs is a regularly measured target cylinder. Target cylinder measurements are not used to correct ambient air measurements, but just to monitor the possible drift of instrument or measurements in general. In long run, these measurements can be used to evaluate the stability of calibration cylinders as well. As the lifetime of a target cylinder is clearly shorter than calibration cylinders, it acts as a link between AS and CAL when visiting CAL for refill. Approximately a year and half lasting test period of travelling cylinders with four ICOS ASs showed mainly good results, i.e. high measurement performance of the evaluated stations. The GAW compatibility goals were fulfilled for all the three mandatory components (CO2: ±0.1 ppm; CH4 & CO: ±2 ppb) for ICOS Class 1 ASs, excluding a couple of individual CO measurements. Not mandatory and extremely challenging component N2O showed weaker measurement performance. When travelling cylinder measurements were compared to target measurements at the ASs, the correlation was clear,

87

P2


Travelling cylinders as a quality control tool in ICOS atmospheric station network

Hermanni Aaltonen1, Juha Hatakka1, Michel Ramonet2, Daniel Rzesanke3, Tuomas Laurila1

1. Finnish Meteorological Institute 2. Laboratoire des Sciences du Climat et de l’Environnement 3. Max-Planck-Institute for Biogeochemistry

The quality control (QC) of European-wide ICOS atmospheric station (AS) network is implemented by several levels and methods from regular leak tests at stations via integrated data checking algorithms to station audits. Travelling QC cylinders is a method having already a long history in measurement networks, like “Round Robins” in GAW stations and “Cucumbers” in CarboEurope. The travelling cylinders approach is tested also in ICOS ASs; do these cylinders give additional value for QC that is not otherwise achieved and is the amount of additional work required in line with the QC benefits? The role of separate QC cylinders in ICOS AS network differs from most of the other measurement networks, since all the ASs are using calibration gases centrally prepared in ICOS Central Analytical Laboratory (CAL). When the calibration gases are consistent, the role of travelling QC cylinders is more like to evaluate the performance and expertise of AS and its personnel than to intercompare the gas concentration levels due to inconsistent calibration cylinders. Naturally, travelling cylinders provide also a tool to follow the stability and possible quality problems of calibration gases in AS network. The instrumentation for greenhouse gas measurements in ICOS ASs is rather uniform due to strict demands for measurement precision. Also each individual instrument is tested before the approval for ICOS AS use. However, instrument’s performance may decline by age, which is very difficult to observe from ambient air measurements only. With calibration gases the picture is basically the same. Gas concentrations inside the cylinder may drift by age, and as the lifetime of a calibration gas cylinder is several years, the drift is difficult to observe before the recalibration at CAL in the end of its lifetime. Routine QC tool for the performance of ICOS ASs is a regularly measured target cylinder. Target cylinder measurements are not used to correct ambient air measurements, but just to monitor the possible drift of instrument or measurements in general. In long run, these measurements can be used to evaluate the stability of calibration cylinders as well. As the lifetime of a target cylinder is clearly shorter than calibration cylinders, it acts as a link between AS and CAL when visiting CAL for refill. Approximately a year and half lasting test period of travelling cylinders with four ICOS ASs showed mainly good results, i.e. high measurement performance of the evaluated stations. The GAW compatibility goals were fulfilled for all the three mandatory components (CO2: ±0.1 ppm; CH4 & CO: ±2 ppb) for ICOS Class 1 ASs, excluding a couple of individual CO measurements. Not mandatory and extremely challenging component N2O showed weaker measurement performance. When travelling cylinder measurements were compared to target measurements at the ASs, the correlation was clear,

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emphasizing the assumed role of target cylinders in QC chain. To maintain the high data quality of the growing AS network, a broad set of QC tools is essential. However, the critical point is to evaluate the QC gains versus workload; are the improvements in the QC of the ambient air measurements in line with the increased workload.

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WCC and QA/SAC activities by JMA

Teruo Kawasaki1, Mayu Yamamoto1, Masashi Yoshida1, Kazuyuki Saito1, Kentaro Kozumi1, Genta Umezawa1, Kazuya Yukita1, Shigeharu Nishida1, Shohei Sato1, Mio Akamatsu1, Atsuya Kinoshita1, Yousuke Sawa1, Kazuhiro Tsuboi2, Kentaro Ishijima2, Hidekazu Matsueda2

1. Japan Meteorological Agency (JMA) 2. Meteorological Research Institute (MRI)

The Japan Meteorological Agency (JMA) serves as the World Calibration Centre (WCC) for methane (CH4) and the Quality Assurance/Science Activity Centre (QA/SAC) for carbon dioxide (CO2) and methane (CH4) in Asia and the South-West Pacific within the framework of the Global Atmosphere Watch (GAW) Programme of the World Meteorological Organization (WMO). As part of the WMO/GAW quality assurance system, the WCC-JMA has a fundamental role in helping to ensure the traceability of GAW network measurements to the WMO primary standard through comparison campaigns. The WCC-JMA organized five rounds of the CH4 reference gas inter-comparison experiments from 2001 to 2018 as one of the WCC activities in Asia and the South-West Pacific in cooperation with NOAA (WMO/CCL, USA), CSIRO (Australia), NIWA (New Zealand), CMA (China), KMA/KRISS (Republic of Korea), IITM (India), MRI (Japan), NIES (Japan), AIST (Japan), NIPR (Japan), and Tohoku University (Japan); the sixth round is still in progress. All the results of the inter-comparison experiments of CH4 from 2001 to 2018 are posted on the WCC-JMA web site (https://ds.data.jma.go.jp/gmd/wcc/wcc.html). In addition to the above GAW-centre activities, the JMA has made long-term continuous observations of atmospheric concentrations of major greenhouse gases such as CO2 and CH4 at Minamitorishima GAW Global Station (MNM) since the 1990s. Other major observation laboratories in Japan also began systematic measurements of atmospheric CO2 and CH4 concentrations using a flask sampling method at MNM in the 2010s. This situation enables to investigate the consistency between observation data of JMA and those of other institutions. The results are also reported in this presentation. We would like to acknowledge all the participants for supporting our WCC/JMA activities.

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WCC and QA/SAC activities by JMA

Teruo Kawasaki1, Mayu Yamamoto1, Masashi Yoshida1, Kazuyuki Saito1, Kentaro Kozumi1, Genta Umezawa1, Kazuya Yukita1, Shigeharu Nishida1, Shohei Sato1, Mio Akamatsu1, Atsuya Kinoshita1, Yousuke Sawa1, Kazuhiro Tsuboi2, Kentaro Ishijima2, Hidekazu Matsueda2

1. Japan Meteorological Agency (JMA) 2. Meteorological Research Institute (MRI)

The Japan Meteorological Agency (JMA) serves as the World Calibration Centre (WCC) for methane (CH4) and the Quality Assurance/Science Activity Centre (QA/SAC) for carbon dioxide (CO2) and methane (CH4) in Asia and the South-West Pacific within the framework of the Global Atmosphere Watch (GAW) Programme of the World Meteorological Organization (WMO). As part of the WMO/GAW quality assurance system, the WCC-JMA has a fundamental role in helping to ensure the traceability of GAW network measurements to the WMO primary standard through comparison campaigns. The WCC-JMA organized five rounds of the CH4 reference gas inter-comparison experiments from 2001 to 2018 as one of the WCC activities in Asia and the South-West Pacific in cooperation with NOAA (WMO/CCL, USA), CSIRO (Australia), NIWA (New Zealand), CMA (China), KMA/KRISS (Republic of Korea), IITM (India), MRI (Japan), NIES (Japan), AIST (Japan), NIPR (Japan), and Tohoku University (Japan); the sixth round is still in progress. All the results of the inter-comparison experiments of CH4 from 2001 to 2018 are posted on the WCC-JMA web site (https://ds.data.jma.go.jp/gmd/wcc/wcc.html). In addition to the above GAW-centre activities, the JMA has made long-term continuous observations of atmospheric concentrations of major greenhouse gases such as CO2 and CH4 at Minamitorishima GAW Global Station (MNM) since the 1990s. Other major observation laboratories in Japan also began systematic measurements of atmospheric CO2 and CH4 concentrations using a flask sampling method at MNM in the 2010s. This situation enables to investigate the consistency between observation data of JMA and those of other institutions. The results are also reported in this presentation. We would like to acknowledge all the participants for supporting our WCC/JMA activities.

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Uncertainty analysis of calibration measurements made by the ICOS Flask and Calibration Laboratory

Armin Jordan1, Daniel Rzesanke1

1. ICOS-CAL, Max-Planck-Institute for Biogeochemistry

The ICOS Central Analytical Laboratories play a central role in assuring the accuracy of atmospheric observations within the European Integrated Carbon Observation System (ICOS). One of the tasks of the Flask and Calibration Laboratory (FCL) is the central provision of reference gases to the ICOS atmospheric network and calibration of these standards based on the WMO calibration scales. One contribution to the uncertainty of ICOS atmospheric measurement data therefore is the scale transfer error introduced by these FCL measurements. Following the recommendations from the 2017 GGMT meeting the methods to estimate the FCL’s measurement uncertainties is presented. We describe which quality control measures are used to characterize the performance of the laboratory’s measurements. This assessment allows the quantification and differentiation between different uncertainty contributions and an overall estimate of the measurement uncertainties. Results from quality control activities made by the field observatories of the ICOS atmospheric station network are used to evaluate the derived measurement uncertainty estimates.

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Development of dimethyl sulfide primary reference gas mixtures for global atmospheric monitoring

Mi Eon Kim1, Ji Hwang Kang1, Yong Doo Kim1, Sangil Lee1


Dimethyl sulfide (DMS) is an important compound in global atmospheric chemistry and climate change. DMS acts as a main precursor of sulfate aerosols in the remote and marine atmosphere. Sulfate aerosols affect directly and indirectly the Earth’s radiation budget by scattering incoming solar radiation and by altering cloud physical properties. The World Metrological Organization (WMO) Global Atmosphere Watch (GAW) has selected DMS as one of the main target reactive gases that should be monitored for better understanding of physical and chemical atmospheric processes. DMS has been monitored globally and reported at nmol/mol levels. However, the measurement uncertainty is too large to track long-term trends of DMS and to advance scientific understanding of its atmospheric physicochemical processes. In this study, two different methods, such as dynamic dilution method (DDM) and static gravimetric method (SGM), have been developed to produce DMS primary reference gas mixtures (PRMs) at nmol/mol levels. For DDM, a sonic nozzle-based dilution system has been calibrated and its dilution factors have been calculated using cavity ringdown spectroscopy and methane PRMs. Results show that the dynamic dilution system generates dynamically DMS in a range of 0.4 to 12 nmol/mol with relative expanded uncertainties of less than 2%. For SGM, DMS PRMs at nmol/mol levels have been prepared gravimetrically in three different aluminum cylinders. Verification results shows that DMS PRMs in aluminum cylinders with a special internal surface coating (Experis) can be prepared with relative expanded uncertainties of less than 0.4% without any physical adsorption loss. The long-term stability of DMS PRMs has been evaluated by comparing SGM PRMs against DDM PRM and tracking the ratio of DMS-to-stable internal standard. PRMs generated by DDM have been compared against SGM PRMs 10 months after preparation of SGM PRMs. Results show that SGM PRMs at 2 – 7 nmol/mol are stable for 10 months with relative expanded uncertainties of less than 2.5% whereas SGM PRM at 0.5 nmol/mol is not stable (i.e., deviated from its gravimetrically determined mole fraction more than 5%). Measurement results of tracking the ratio show that SGM PRMs are projected to be stable for more than 60 months within a relative expanded uncertainty of 3%.

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Development of dimethyl sulfide primary reference gas mixtures for global atmospheric monitoring

Mi Eon Kim1, Ji Hwang Kang1, Yong Doo Kim1, Sangil Lee1


Dimethyl sulfide (DMS) is an important compound in global atmospheric chemistry and climate change. DMS acts as a main precursor of sulfate aerosols in the remote and marine atmosphere. Sulfate aerosols affect directly and indirectly the Earth’s radiation budget by scattering incoming solar radiation and by altering cloud physical properties. The World Metrological Organization (WMO) Global Atmosphere Watch (GAW) has selected DMS as one of the main target reactive gases that should be monitored for better understanding of physical and chemical atmospheric processes. DMS has been monitored globally and reported at nmol/mol levels. However, the measurement uncertainty is too large to track long-term trends of DMS and to advance scientific understanding of its atmospheric physicochemical processes. In this study, two different methods, such as dynamic dilution method (DDM) and static gravimetric method (SGM), have been developed to produce DMS primary reference gas mixtures (PRMs) at nmol/mol levels. For DDM, a sonic nozzle-based dilution system has been calibrated and its dilution factors have been calculated using cavity ringdown spectroscopy and methane PRMs. Results show that the dynamic dilution system generates dynamically DMS in a range of 0.4 to 12 nmol/mol with relative expanded uncertainties of less than 2%. For SGM, DMS PRMs at nmol/mol levels have been prepared gravimetrically in three different aluminum cylinders. Verification results shows that DMS PRMs in aluminum cylinders with a special internal surface coating (Experis) can be prepared with relative expanded uncertainties of less than 0.4% without any physical adsorption loss. The long-term stability of DMS PRMs has been evaluated by comparing SGM PRMs against DDM PRM and tracking the ratio of DMS-to-stable internal standard. PRMs generated by DDM have been compared against SGM PRMs 10 months after preparation of SGM PRMs. Results show that SGM PRMs at 2 – 7 nmol/mol are stable for 10 months with relative expanded uncertainties of less than 2.5% whereas SGM PRM at 0.5 nmol/mol is not stable (i.e., deviated from its gravimetrically determined mole fraction more than 5%). Measurement results of tracking the ratio show that SGM PRMs are projected to be stable for more than 60 months within a relative expanded uncertainty of 3%.

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New calibration system for methane and carbon dioxide at JMA Kentaro Ishijima1, Hidekazu Matsueda1, Kazuhiro Tsuboi1, Kentaro Kozumi2, Genta Umezawa2, Teruo Kawasaki2, Yousuke Sawa2 1. Meteorological Research Institute 2. Japan Meteorological Agency

New calibration systems of methane (CH4) and carbon dioxide (CO2) standard gases have been developed at the Japan Meteorological Agency (JMA) in collaboration with the Meteorological Research Institute. The new CH4 calibration system is based on a wavelength-scanned cavity ring-down spectroscopy (WS-CRDS) analyzer [1]. Our system shows high precision (0.06 nmol mol-1) and reproducibility (0.07 nmol mol-1) and good linearity against the WMO CH4 mole fraction scale. CH4 calibration results by the new system agree well with those by the previous GC-FID based JMA calibration system. The precision of the new WS-CRDS CH4 calibration system is found to be better by one order of magnitude than that of the previous GC-FID system. We also evaluate the stability and consistency of the JMA calibrations over the past 10 years by examining data from the World Calibration Centre (WCC) Round Robin comparison experiments in Asia and the regions in the southwest Pacific. The results ensure the traceability to the WMO scale of atmospheric CH4 measurements for the JMA/WCC comparisons. The new CO2 calibration system is based on an off-axis integrated cavity output spectroscopy (ICOS). The analyzer can separately detect four major isotopologues of CO2, enabling to significantly reduce so-called “isotope effect” in NDIR measurement of CO2 mole fraction. We employ a method by Tans et al. [2] for calculating CO2 mole fraction of the calibrated gases. The precision of CO2 mole fraction measurement by the new system is ~0.02 µmol mol-1, which is slightly surpassed by the previous NDIR based system (~ 0.014 µmol mol-1). However, the reproducibility is better for the new system (~0.01 µmol mol-1), compared to that for the previous system (~0.03 µmol mol-1), suggesting the high stability of the laser analyzer. Linearity, which is here defined as curvature of the quadratic calibration curve subtracted by the linear calibration line, is better by one order of magnitude for the new system than the previous system. Mole fraction values calibrated by the new and previous systems with the same standard scale show some differences, which depend on the mole fraction of the calibrated gases, probably due to the difference of calibration curve between both the analyzers.

References

[1] Matsueda, H., K. Tsuboi, T. Kawasaki, M. Nakamura, K. Saito, A. Takizawa, K. Dehara, and S. Hosokawa, 2018, Evaluation of a new methane calibration system at JMA for WCC Round Robin experiments, Papers in Meteor. and Geophys, 67, 57–67, doi:10.2467/mripapers.67.57.

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[2] Tans, P. P., A. M. Crotwell, and K. W. Thoning, 2017, Abundances of isotopologues and calibration of CO2 greenhouse gas measurements, Atmos. Meas. Tech., 10, 2669-2685, doi.org/10.5194/amt-10-2669-2017.

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[2] Tans, P. P., A. M. Crotwell, and K. W. Thoning, 2017, Abundances of isotopologues and calibration of CO2 greenhouse gas measurements, Atmos. Meas. Tech., 10, 2669-2685, doi.org/10.5194/amt-10-2669-2017.

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Influences of thermal fractionation and adsorption on CO2 standard mixture gravimetrically prepared using multiple steps

Nobuyuki Aoki1, Shigeyuki Ishidoya2, Shohei Murayama2

1. National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology (NMIJ/AIST) 2. Environmental Management Research Institute, National Institute of Advanced Industrial Science and Technology (AIST)

It was reported by some past studies that when half contents of one cylinder (mother) are transferred to an equal size cylinder (daughter), CO2 mole fractions in the daughter cylinder and the mother cylinder after transfer are higher and lower, respectively, than that in the mother cylinder before transfer. We have also detected that CO2 mole fractions in daughter cylinders after transfer are about 0.2 ppm lower than their mother cylinders by the half content transfer experiment. Moreover, we measured O2/N2, Ar/N2 and isotopic ratios of O2, N2 and Ar in the mother and daughter cylinders. The results suggested that the thermally-diffusive fractionation simultaneously occurred during the transfer. Therefore, if the CO2 standard mixture is prepared by multiple steps, then the CO2 mole fraction in the mixture should be different from the gravimetrically assigned values due not only to a selective adsorption of CO2 to the inner wall of the cylinder but also to the thermal fractionation during the multiple transfer. To evaluate the influence of the fractionations, we examined the shift of CO2 mole fractions in standard mixtures by a 3-step method depending on residual pressures of a source gas (a second step standard mixture, an initial inner pressure of 12 MPa). The inner pressure of the source gas decreased from 12 MPa to 1 MPa to prepare six standard mixtures by the 3-step method, and their CO2 mole fractions were determined using a Picarro G2301 calibrated by the standard mixtures prepared by the 1-step method. The gravimetrically assigned CO2 mole fractions in the standard mixtures prepared firstly and lastly shifted from 0.1 ppm to -0.1 ppm with respect to the determined mole fractions. Results of the mother-daughter transfer experiments for other greenhouse gases (CH4, N2O, CO) will also be presented and discussed.

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GHGs data comparison between NIES observation network (aircrafts, stations and ships) in the Asian-Pacific region and GOSAT Shohei Nomura1, Hitoshi Mukai1, Yukio Terao1, Toshinobu Machida1, Motoki Sasakawa1, Isamu Morino1 1. National Institute for Environmental Studies

NIES has been operated the NIES observation network for GHGs in the Asian-Pacific region by using the aircraft (CONTRAIL project), stations (e.g. Japan, India and Malaysia) and ships (e.g. Japan-USA, Japan-Australia/New Zealand, Japan-Southeast Asia). Here, we compared the data (CO2 and CH4) of NIES observation network with the GOSAT L2 CO2 corrected data (v2.75), whose biases (land and sea) were corrected by comparison with TCCON data. However, some data was found to deviate from our estimation, suggesting that further investigation was needed.

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GHGs data comparison between NIES observation network (aircrafts, stations and ships) in the Asian-Pacific region and GOSAT Shohei Nomura1, Hitoshi Mukai1, Yukio Terao1, Toshinobu Machida1, Motoki Sasakawa1, Isamu Morino1 1. National Institute for Environmental Studies

NIES has been operated the NIES observation network for GHGs in the Asian-Pacific region by using the aircraft (CONTRAIL project), stations (e.g. Japan, India and Malaysia) and ships (e.g. Japan-USA, Japan-Australia/New Zealand, Japan-Southeast Asia). Here, we compared the data (CO2 and CH4) of NIES observation network with the GOSAT L2 CO2 corrected data (v2.75), whose biases (land and sea) were corrected by comparison with TCCON data. However, some data was found to deviate from our estimation, suggesting that further investigation was needed.

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The Atmospheric Pressure Effect on N2O Analysis and the Use of a Exhaust Chamber to Minimize this Effect Caio Correia1, Luciana Gatti2, Lucas Domingues1, Ricardo dos Santos2, Raiane Neves2, Luciano Marani2, Stephane Crispim2, Maisa Ribeiro2, Manuel Gloor3, John Miller4, Wouter Peters5 1. IPEN/CQMA/LQA (Nuclear and Energy Research Institute), Sao Paulo, SP, Brazil 2. INPE/CCST/LaGEE (National Institute of Space Research) 3. University of Leeds, School of Geography, UK 4. NOAA/ESRL/GMD (Global Monitoring Division), Boulder, Colorado, US 5. Centre for Isotope research Energy and Sustainability Research Institute Groningen, Groningen University, The Netherlands

In the past we’ve demonstrated the influence of room conditions in gas chromatography analysis of nitrous oxide (N2O) using Electron Capture Detector (ECD) and micro Electron Capture Detector (µECD), which is basically the same detector with a smaller chamber, both using an Argon (95%) – Methane (5%) mixture as carrier gas. This gas provides a higher ECD sensitivity than N2 or Ar gases [1]. The pre-column and column used were both stainless steel 3/16” ED, 183cm length, packed with HayeSep® Q 100/120 mesh. Loop with 15ml volume and oven with constant temperature of 70°C. The µECD temperature was 350°C. Recently our laboratory was asked by the National Nuclear Energy Commission (CNEN) to build a laboratory exhaust chamber to keep the chromatography in, in order to exhaust any sort of leaks, once the ECD uses a radioactive source of Ni63. This exhaust chamber is equipped with an exhaust fan which is kept turned on the whole time. We discarded the influences of CO2 concentrations, and also temperature influence over our analysis in the past studies, these same tests suggested a covariance between the detector response and the laboratory room pressure, we decided to test if the exhaust chamber can act like a chamber and reduce the outside pressure influence over the analysis. This change make the analysis more stable, reducing the impact of changes in the pressure room. These studies are relevant as the N2O is the third most important natural greenhouse in terms of atmospheric radiative forcing, (WMO, 2018), then the efforts in produce a better precision in it analysis is very valuable and also ECD is the most used detector to analyze N2O in laboratories.

Reference

[1] Wang, Y., Ling, H., A new carrier gas for accurate measurements of N2O by GC-ECD. Advances in Atmospheric Sciences, Vol. 27, N0. 6, 2010, 1322-1330. WMO GREENHOUSE GAS BULLETIN 14. The State of Greenhouse Gases in the Atmosphere Based on Global Observations through 2017. No. 14, 22 November 2018. https://library.wmo.int/doc_num.php?explnum_id=5455 Acknowledgments: NOAA, NERC, ERC, FAPESP, CNPq and MCTi

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Ambient air performance of N2O Los Gatos analysers at Hohenpeissenberg Dagmar Kubistin1, Matthias Lindauer1, Arnold Sabrina1, Laurent Olivier2, Rivier Leonard2, Plass-Dülmer Christian1 1. German Meteorological Service (DWD), Meteorological Observatory Hohenpeissenberg, Germany 2. Laboratoire des Sciences du Climat et de l'Environnement (LSCE/IPSL), UMR CEA-CNRS-UVSQ, Gif sur Yvette, France

Long term N2O observations subsequently become available at the German atmospheric ICOS (Integrated Carbon Observation System) stations. Since the WMO compatibility goal of 0.1 ppb is challenging to fulfil, all deployed Los Gatos Analysers (LGR- N2O/CO/H2O –913-0015-EP) are tested under laboratory conditions by the ICOS-Metrology Lab (ATC-MLAB) and under real atmospheric conditions at the GAW station Hohenpeissenberg (HPB). The HPB-LGR device was chosen to act as a reference instrument and each LGR instrument runs for a minimum of one month in parallel before distributing to the remaining ICOS station. The sample line is operated under low pressure (0.5 bar) and an external Nafion dryer is installed in front of each LGR. The performance and stability of a series of LGR is shown for the ambient air comparison as well as first results of the N2O observations at the equipped stations.

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Ambient air performance of N2O Los Gatos analysers at Hohenpeissenberg Dagmar Kubistin1, Matthias Lindauer1, Arnold Sabrina1, Laurent Olivier2, Rivier Leonard2, Plass-Dülmer Christian1 1. German Meteorological Service (DWD), Meteorological Observatory Hohenpeissenberg, Germany 2. Laboratoire des Sciences du Climat et de l'Environnement (LSCE/IPSL), UMR CEA-CNRS-UVSQ, Gif sur Yvette, France

Long term N2O observations subsequently become available at the German atmospheric ICOS (Integrated Carbon Observation System) stations. Since the WMO compatibility goal of 0.1 ppb is challenging to fulfil, all deployed Los Gatos Analysers (LGR- N2O/CO/H2O –913-0015-EP) are tested under laboratory conditions by the ICOS-Metrology Lab (ATC-MLAB) and under real atmospheric conditions at the GAW station Hohenpeissenberg (HPB). The HPB-LGR device was chosen to act as a reference instrument and each LGR instrument runs for a minimum of one month in parallel before distributing to the remaining ICOS station. The sample line is operated under low pressure (0.5 bar) and an external Nafion dryer is installed in front of each LGR. The performance and stability of a series of LGR is shown for the ambient air comparison as well as first results of the N2O observations at the equipped stations.

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Results of a Long-Term International Comparison of Greenhouse Gas and Isotope Measurements at the Global Atmosphere Watch (GAW) Station in Alert, Nunavut, Canada Doug Worthy1, Michele Rauh1, Lin Huang1, Ken Masarie2, Ray Langenfelds3, Colin Allison3, Sylvia England Michele4, James White4, Martina Schmidt5, Michel Ramonet5, Armin Jordan6, Willi Brand6, Edward Dlugokencky7, Patricia Lang7, Ralph Keeling8, Ingeborg Levin9, Felix Vogel9 1. Environment and Climate Change Canada, Climate Research Division, Toronto, Ontario, Canada 2. Skydata Solutions LLC, Boulder, Colorado, USA 3. Centre for Australian Weather and Climate Research / CSIRO Marine and Atmospheric Research, Aspendale, Victoria, Australia 4. Institute of Arctic and Alpine Research, University of Colorado, Boulder Colorado, USA 5. Laboratoire des Sciences du Climat et de l’Environnement, Gif sur Yvette, France 6. Max Planck Institute for Biogeochemistry, Jena, Germany 7. National Oceanic and Atmospheric Administration, Earth System Research Laboratory, Boulder, Colorado, USA 8. Scripps Institute of Oceanography, La Jolla, California, USA 9. Institut Fur Umweltphysik, Heidelberg University, Heidelberg, Germany

Since 1999, Environment and Climate Change Canada (ECCC) has been operating a multi-laboratory comparison of measurements of atmospheric air at the Global Atmosphere Watch (GAW) Alert Observatory located on the northern tip of Ellesmere Island in the high Canadian Arctic. The goal of this ongoing comparison experiment is to evaluate the compatibility of measurements of atmospheric CO2, CH4, N2O, SF6, and the stable isotopes of CO2 (13C, 18O) among independent laboratories. The motivation behind the effort is to determine if independent atmospheric records can be used together in studies without introducing significant bias. The seven participating laboratories are the Commonwealth Scientific and Industrial Research Organization (CSIRO), Max Planck Institute for Biogeochemistry (MPI-BGC), University of Heidelberg, Institut für Umweltphysik (UHEI-IUP), Laboratoire des Sciences du Climat et de l'Environnement (LSCE), Scripps Institution of Oceanography (SIO), the National Oceanic and Atmospheric Administration (NOAA) in collaboration with the Stable Isotope Laboratory at the University of Colorado Institute of Arctic and Alpine Research (INSTAAR), and the host laboratory, ECCC. The results presented here are based on a comparison of measurements from co-located weekly air samples collected in each laboratory’s flasks. Flasks are returned to each laboratory for analysis. Because the comparison experiment encompasses the entire atmospheric measurement process, observed differences in the co-located measurements may be due to problems with air sample collection, storage, extraction, and analysis; data processing; and maintenance of the laboratory calibration scale. Our measure of success is linked to measurement compatibility recommendations outlined by the World Meteorological Organization (WMO) GAW greenhouse gas measurement community. Results from this 18-year comparison experiment show the co-located CSIRO,

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MPI-BGC, SIO, UHEI-IUP, ECCC, and NOAA atmospheric CO2 records from Alert are consistent to within ±0.1 ppm CO2, and the co-located CSIRO, MPI-BGC, UHEI-IUP, ECCC, and NOAA atmospheric CH4 records from Alert are consistent to within ±2 ppb CH4. Results from co-located comparison experiments between CSIRO, SIO, and NOAA at other locations further suggest that these findings at Alert are not unique to Alert but likely extend to atmospheric CO2 records across the CSIRO, SIO, and NOAA observing networks and to atmospheric CH4 records across the CSIRO and NOAA networks. While meeting the WMO recommendations for CO2 and CH4 measurement compatibility, it is important to keep in mind that we often observe periods where measurement differences exceed the WMO target levels and may persist as systematic bias for months or years. We find that only a few laboratories meet these compatibility goals for the other trace gas species and isotopes, and only when results are averaged over many years. These independent measurement records can still be used together for some specific purposes even though they may not all be consistent to within the WMO/GAW recommended compatibility window if we provide users with a defensible estimate of the overall measurement compatibility derived from our findings. Our estimate of overall measurement compatibility when combining Alert flask air records from each of the participating laboratories is (0.54 to +0.53) ppm CO2, (0.10 to +0.06)‰ 13C-CO2, (0.62 to +0.45)‰ 18O-CO2, (5.0 to +6.2) ppb CH4, (0.75 to +1.19) ppb N2O, and (0.14 to +0.09) ppt SF6. This upper and lower limit contains 95% of the entire difference distribution for each trace gas species and isotope and represents our best estimate of measurement compatibility based on this work.

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MPI-BGC, SIO, UHEI-IUP, ECCC, and NOAA atmospheric CO2 records from Alert are consistent to within ±0.1 ppm CO2, and the co-located CSIRO, MPI-BGC, UHEI-IUP, ECCC, and NOAA atmospheric CH4 records from Alert are consistent to within ±2 ppb CH4. Results from co-located comparison experiments between CSIRO, SIO, and NOAA at other locations further suggest that these findings at Alert are not unique to Alert but likely extend to atmospheric CO2 records across the CSIRO, SIO, and NOAA observing networks and to atmospheric CH4 records across the CSIRO and NOAA networks. While meeting the WMO recommendations for CO2 and CH4 measurement compatibility, it is important to keep in mind that we often observe periods where measurement differences exceed the WMO target levels and may persist as systematic bias for months or years. We find that only a few laboratories meet these compatibility goals for the other trace gas species and isotopes, and only when results are averaged over many years. These independent measurement records can still be used together for some specific purposes even though they may not all be consistent to within the WMO/GAW recommended compatibility window if we provide users with a defensible estimate of the overall measurement compatibility derived from our findings. Our estimate of overall measurement compatibility when combining Alert flask air records from each of the participating laboratories is (0.54 to +0.53) ppm CO2, (0.10 to +0.06)‰ 13C-CO2, (0.62 to +0.45)‰ 18O-CO2, (5.0 to +6.2) ppb CH4, (0.75 to +1.19) ppb N2O, and (0.14 to +0.09) ppt SF6. This upper and lower limit contains 95% of the entire difference distribution for each trace gas species and isotope and represents our best estimate of measurement compatibility based on this work.

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How to deal with water vapor for Greenhouse gas dry mole fraction measurement with Cavity Enhanced Spectrometer: water vapor correction vs Nafion dryer.

Olivier Laurent1, Carole Philippon1, Camille Yver kwok1, Leonard Rivier1

1. Laboratoire des Sciences du Climat et l’Environnement (LSCE/IPSL), UMR CNRS-CEA-UVSQ, Université Paris Saclay,91191 Gif-sur-Yvette, France

Greenhouse gas (GHG) mole fraction in the atmosphere is usually presented as mole fraction in dry air in order to avoid the effect of the high variability of the water vapor content in the atmosphere. The first technology used for GHG measurement, gas chromatography or non-dispersive infra-red spectroscopy, required to dry the air sample prior to analysis at a dew point lower than -50°C. The emergence of new GHG analyzers using infrared Enhanced Cavity Spectroscopy which measure the water vapor content in the air sample, allows providing the dry mole fraction of GHG without any drying system upstream by applying appropriate correction of the water vapor effects (dilution, pressure broadening…). This presentation presents the results of the tests conducted at the Metrology Lab of the ICOS Atmosphere Thematic Centre (ATC) located at LSCE in France. The tests focus on the performance of the water vapor correction on Cavity Enhanced Spectrometer, in particular its stability over time, compared to the use of Nafion dryer which induces bias on the measurement of few species. It attempts to propose the most appropriate strategy to fulfil the WMO and ICOS specifications in term of compatibility goals.

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Metrological performance assessment of different Cavity Enhanced Spectrometer to measure atmospheric nitrous oxide.



The Metrology Lab of the ICOS Atmosphere Thematic Centre (ATC), located at LSCE in Gif-sur-Yvette, France, has tested different nitrous oxide Infra red Spectrometer in order to assess their compliancy to ICOS specifications for field measurement within the European ICOS network. The conducted tests consisted in characterizing the metrological performance in term of short and long term repeatability, drift, linearity, cross sensitivity with other atmospheric compounds, thermal and pressure sensitivity, water vapor correction (to derive the dry mixing ratio) among others. The presentation will show the main results of the assessment conducted in laboratory as well as field validation.

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Metrological performance assessment of different Cavity Enhanced Spectrometer to measure atmospheric nitrous oxide.



The Metrology Lab of the ICOS Atmosphere Thematic Centre (ATC), located at LSCE in Gif-sur-Yvette, France, has tested different nitrous oxide Infra red Spectrometer in order to assess their compliancy to ICOS specifications for field measurement within the European ICOS network. The conducted tests consisted in characterizing the metrological performance in term of short and long term repeatability, drift, linearity, cross sensitivity with other atmospheric compounds, thermal and pressure sensitivity, water vapor correction (to derive the dry mixing ratio) among others. The presentation will show the main results of the assessment conducted in laboratory as well as field validation.

P14


Laboratory Investigation of CO2 Biases Related to Water Vapor Surface Adsorption in Air Samples Stored in Glass Flasks

Don Neff1,2, Alici Edwards3, Colm Sweeney1, Arlyn Andrews1, Kathryn McKain1,2

1. NOAA 2. CIRES 3. Science and Technology Corporation

Laboratory experiments have revealed that the presence of water vapor in atmospheric air samples collected and stored in glass flasks, in conjunction with contamination on the flask surface, can significantly bias measurements of carbon dioxide in these samples. The process can bias the measured dry-air mole fraction of carbon dioxide, ranging from a 0.1 ppm to more than a 1.0 ppm bias in the sample relative to the ambient air initially collected.

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P15


Estimation of greenhouse gas emission factors based on observed covariance of CO2, CH4, N2O and CO mole fractions

Laszlo Haszpra1, Zita Ferenczi2, Zoltan Barcza3

1. Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences 2. Hungarian Meteorological Service 3. Dep. of Meteorology, Eötvös Loránd University, Budapest

On the base of observed covariance between carbon dioxide, methane, carbon monoxide and nitrous oxide atmospheric dry air mole fraction in a region of the Pannonian (Carpathian) Basin during three cold air pool episodes in January-February 2017, emission factors relative to carbon dioxide were determined. For the determination of the emission of carbon dioxide, a simple boundary-layer budget model was compiled. The model gave 7.34 g m-2 day-1 carbon dioxide emission for the footprint area of the measurements on average for the period of the episodes. The 6.7-13.8 nmol μmol-1, 0.15-0.31 nmol μmol-1 and 15.0-25.8 nmol μmol-1 ratios for CH4:CO2, N2O:CO2 and CO:CO2, respectively, correspond to 17.9-37.9 mg m-2 day-1 methane, 1.1-2.2 mg m-2 day-1 nitrous oxide and 69.9-120.4 mg m-2 day-1 carbon monoxide emissions for the region. These values are somewhat higher than the officially reported bottom-up annual national averages for Hungary, which are explained by the winter conditions and intensive domestic heating.

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P15


Estimation of greenhouse gas emission factors based on observed covariance of CO2, CH4, N2O and CO mole fractions

Laszlo Haszpra1, Zita Ferenczi2, Zoltan Barcza3

1. Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences 2. Hungarian Meteorological Service 3. Dep. of Meteorology, Eötvös Loránd University, Budapest

On the base of observed covariance between carbon dioxide, methane, carbon monoxide and nitrous oxide atmospheric dry air mole fraction in a region of the Pannonian (Carpathian) Basin during three cold air pool episodes in January-February 2017, emission factors relative to carbon dioxide were determined. For the determination of the emission of carbon dioxide, a simple boundary-layer budget model was compiled. The model gave 7.34 g m-2 day-1 carbon dioxide emission for the footprint area of the measurements on average for the period of the episodes. The 6.7-13.8 nmol μmol-1, 0.15-0.31 nmol μmol-1 and 15.0-25.8 nmol μmol-1 ratios for CH4:CO2, N2O:CO2 and CO:CO2, respectively, correspond to 17.9-37.9 mg m-2 day-1 methane, 1.1-2.2 mg m-2 day-1 nitrous oxide and 69.9-120.4 mg m-2 day-1 carbon monoxide emissions for the region. These values are somewhat higher than the officially reported bottom-up annual national averages for Hungary, which are explained by the winter conditions and intensive domestic heating.

P16


Operation of new WDCGG website and started of satellite data collection

Atsuya Kinoshita1, Saki Ohkubo1, Shou Shimamura1, Yousuke Sawa1

1. Japan Meteorological Agency

The World Data Centre for Greenhouse Gases (WDCGG) is one of the World Data Centres (WDCs) under the Global Atmosphere Watch (GAW) programme, which has been operating since 1990. It serves to collect, archive and distribute data on such gases (e.g., CO2, CH4, CFCs and N2O) and other related gases (such as CO) in the atmosphere, which are measured under GAW and other programmes. The new WDCGG website (https://gaw.kishou.go.jp/) started in August 2018, incorporating many requests from the data providers and users. Here are some examples of improvements: - Better visibility of the data - Introduction of detailed metadata with flexible length - Addition of common data flags for WDCGG based on the site specific flags - Start of sending relevant information such as numbers of downloads to the data providers The data submitted to WDCGG are used for global analysis for key greenhouse gases in the WMO Greenhouse Gas Bulletin, which is annually published before COP. Detailed data and analyses are also provided in WMO WDCGG Data Summary. We believe that these publications/activities meet the expectations for updated information on greenhouse gas levels supported by global observational efforts and growing data availability. In addition, WDCGG began online provision of CO2 observation data from Japan’s Ibuki Greenhouse gases Observing SATellite (GOSAT) in March 2019. Integration of remote sensing satellite data and existing surface-based in situ data is expected to promote the wider use of this information and facilitate long-term monitoring of global distribution and sub-continental CO2 emission/absorption estimates. WDCGG plans to continue improving its services for the collection, archiving and distribution of data worldwide to support the monitoring of climate change and policy making, thereby helping to reduce environmental risks to society. We would like to acknowledge all the data contributors and users for supporting our WDCGG activities.

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P17


Enhanced terrestrial carbon uptake over South Korea revealed by atmospheric CO2 measurements

Jeongmin Yun1, Su-Jong Jeong1, Chang-Hoi Ho1, Hoonyoung Park1, Junjie Liu2

1. Seoul National University 2. Jet Propulsion Laboratory

The exact assessment of the role of terrestrial carbon balance in the regional carbon cycle is critical for understanding climate change. However, the lack of numbers of local measurements limits our knowledge of the regional-scale terrestrial carbon cycle. In this study, we explored changes in the regional-scale terrestrial carbon cycle over South Korea by utilizing long-term atmospheric CO2 measurements for the period 1999–2017. The influence of the regional land surface on atmospheric CO2 was estimated from the difference between the CO2 concentrations (ΔCO2) for two major wind directions: wind from the land sector and wind from the ocean sector. We found a significant decreasing trend in ΔCO2 of 4.75 ppmv decade-1 (p < 0.05) during the growing season (May through October) suggesting that the regional land carbon uptake increased relative to the surrounding ocean areas. For the same period, the remotely sensed normalized difference vegetation index increased by 0.03 decade-

1 across 90% of the South Korean territory. In accordance with the nationwide vegetation greening trend, process-based terrestrial model simulations estimated that the vegetation increase would lead to an enhancement of terrestrial carbon uptake by 19.5 g C m-2 decade-1 for the growing season. Based on the multiple lines of evidence from surface observations, satellite data, and modeling, our results suggest that the terrestrial carbon uptake over South Korea has been enhanced during the recent two decades. These findings highlight the fact that atmospheric CO2 measurements could open up the possibility of detecting regional changes in the terrestrial carbon cycle in data-limited environments.

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P17


Enhanced terrestrial carbon uptake over South Korea revealed by atmospheric CO2 measurements

Jeongmin Yun1, Su-Jong Jeong1, Chang-Hoi Ho1, Hoonyoung Park1, Junjie Liu2

1. Seoul National University 2. Jet Propulsion Laboratory

The exact assessment of the role of terrestrial carbon balance in the regional carbon cycle is critical for understanding climate change. However, the lack of numbers of local measurements limits our knowledge of the regional-scale terrestrial carbon cycle. In this study, we explored changes in the regional-scale terrestrial carbon cycle over South Korea by utilizing long-term atmospheric CO2 measurements for the period 1999–2017. The influence of the regional land surface on atmospheric CO2 was estimated from the difference between the CO2 concentrations (ΔCO2) for two major wind directions: wind from the land sector and wind from the ocean sector. We found a significant decreasing trend in ΔCO2 of 4.75 ppmv decade-1 (p < 0.05) during the growing season (May through October) suggesting that the regional land carbon uptake increased relative to the surrounding ocean areas. For the same period, the remotely sensed normalized difference vegetation index increased by 0.03 decade-

1 across 90% of the South Korean territory. In accordance with the nationwide vegetation greening trend, process-based terrestrial model simulations estimated that the vegetation increase would lead to an enhancement of terrestrial carbon uptake by 19.5 g C m-2 decade-1 for the growing season. Based on the multiple lines of evidence from surface observations, satellite data, and modeling, our results suggest that the terrestrial carbon uptake over South Korea has been enhanced during the recent two decades. These findings highlight the fact that atmospheric CO2 measurements could open up the possibility of detecting regional changes in the terrestrial carbon cycle in data-limited environments.

P18


Comparison of reginal simulation of terrestrial CO2 flux from the updated version of CarbonTracker Asia (CTA) with FLUXCOM and other inversions over East Asia

Samuel Takele Kenea1, Lev Labzovskii1, Tae-Young Goo1, Young-Suk Oh1, Shanlan Li1, Young-Hwa Byun1

1. Climate Research Division, National Institute of Meteorological Sciences, Jeju-do, Republic of Korea

The terrestrial carbon fluxes exhibit strong variability among the components of carbon cycle, which drive the temporal variations in the growth rate of atmospheric CO2 concentrations. Previous findings pointed out that there are large uncertainties still remained in the estimates of net ecosystem exchange of CO2 with atmosphere in East Asia (EA), particularly, in the boreal and eastern part of temperate EA. This study is emphasized on the evaluation of model performance in NEE estimations over EA. Here, we used nested grid CarbonTracker model (CTA with updated version of CT2017) estimates of NEE flux and compare with data driven NEE flux from FLUXCOM as well as employing the global inverse model outputs derived from Copernicus Atmospheric Monitoring Service (CAMS Monitoring Atmospheric Composition and Climate (MACC) and Jena in EA during 2001-2013. CTA is one of the data assimilation systems that use an ensemble Kalman filter method to optimize fluxes on ecoregion. This work highlights the differences on mean and standard deviation (SD) of NEE flux estimates between CTA and CT2017 NOAA (National Oceanic and Atmospheric Administration Earth System) with respect to the spatial resolution change. We noticed a reduction of uncertainty of NEE in CTA in the southeast boreal Asia and southeast temperate Eurasia during the peak of growing season season. This reduction is evidenced due to the introduction of additional constraint data such as aircraft CO2 measurements from CONTRAIL (Comprehensive Observation Network for Trace gases by Airline). We found that CTA aggregated NEE fluxes are slightly better correlated with the data driven fluxes particularly over croplands, conifer forests, fields/woods/savanna land cover types than CT2017. A good agreement between them is prominent in the areas where more observation data are used as a constraint and poor agreement is confined in the areas with no observation data coverage. Moreover, a contrasting NEE pattern is identified in tropical Asia. The influence of prior NEE is high on the posterior estimates of NEE from CTA in the region with no observation data. We also compare the time series of the aggregated regional NEE flux and show that CTA underestimates carbon uptake in summer and overestimates outgassing in winter. This finding suggests a tendency of vertical shifting on the pattern of NEE flux without phase shift. In the peak growing season, the net aggregated flux estimated from CTA and FLUXCOM are 0.5 and 1.7 g C m-2 d-1, respectively. However, CTA estimate is nearly consistent with CAMS and MACC, and slightly underestimated against Jena. Furthermore, the spatial correlation between CTA and

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FLUXCOM showed positive correlation (R > 0.6 0) in temperate broadleaf and mixed forests areas over Korea, Japan, and in the north eastern part of the domain, and negative correlation, about -0.63, in tropical and subtropical moist broadleaf forests in southern part of the given domain. We also examined the simulated annual mean NEE flux during daytime and nighttime with data-driven flux; this approach could benefit to indicate the modeling errors associated with the planetary boundary layer (PBL). A noticeable difference between them is largely confined in the southern part of the region of interest.

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FLUXCOM showed positive correlation (R > 0.6 0) in temperate broadleaf and mixed forests areas over Korea, Japan, and in the north eastern part of the domain, and negative correlation, about -0.63, in tropical and subtropical moist broadleaf forests in southern part of the given domain. We also examined the simulated annual mean NEE flux during daytime and nighttime with data-driven flux; this approach could benefit to indicate the modeling errors associated with the planetary boundary layer (PBL). A noticeable difference between them is largely confined in the southern part of the region of interest.

P19


Recent GAW activities of KMA

Yuwon Kim1, Haeyoung Lee1, Seongwoon Noh1, Sanghoon Kim1, Jae-Cheon Choi1

1. Korea Meteorological Administration

The KMA monitors 36 components in the fields of greenhouse gases, reactive gases, aerosols, UV, stratospheric ozone, atmospheric radiation, and total atmospheric deposition, in accordance with the measurement recommendations of GAW program at four main stations which are located in the west (at Anmyeondo, Chungnam Province), south (at Gosan, Jeju), and east (at Pohang and Ulleungdo, Gyungbook Province) of the Korean Peninsula, respectively. Based on the monitoring results, every July, it publishes a Korea Global Atmosphere Watch Report in Korean and its summary in English, which show the results of observations along with QA/QC methods, causes of data missing, and specific notes. According to the 2018 Korea Global Atmosphere Watch Report, annual mean of CO2 in 2018 was the highest at Anmyeondo (415.2 ppm), followed by Gosan (414.3 ppm) and Ulleungdo (412.7 ppm), which indicates that the concentration in 2018 has increased compared to the previous year. The CO2 at Anmyeondo station,which has the longest record of CO2 in Korea, showed that its absolute difference from the annual mean in 2017 increased by 3.0 ppm, higher than the past decade's average annual increase of 2.4 ppm/yr. Other observation results in Korea will be also showed in this GGMT-2019. In addition, we will introduce the recent KMA's activities related to the SF6 WCC and the pilot project on WMO IG3IS.

108

P20


Abrupt changes of atmospheric CO2 during the last glacial termination and the Common Era

Jinho Ahn1, Hunkyu Lee1, Christo Buizert2, Ed Brook2

1. Seoul National University 2. Oregon State University

Recent high-resolution ice core records from WAIS (West Antarctic Ice Sheet) Divide, Dome C and Law Dome ice cores show abrupt changes of atmospheric CO2 concentration at specific time intervals on decadal to centennial timescales. The abrupt features may help us better understand non-linear nature of carbon cycle feedbacks to climate changes and will be useful in improving predictions for future climate changes. However, the integrity of ice and analytical methods remain not entirely proved. In this context, analyses for multiple cores with a high-precision method should be accomplished to accurately constrain nature of the CO2 changes. Here we present new ice core results from Siple Dome and Styx ice cores, Antarctica that cover the last glacial deglaciation and the Common Era. Compared with existing records, 1-2% of CO2 concentration offsets are found among different Antarctic ice cores. However, magnitudes and speeds of the CO2 changes in WAIS Divide ice are relatively well confirmed: The Siple Dome record during the last glacial termination clearly shows abrupt increases of CO2 with a rate of 10 ppm per century. The Styx record during the Common Era agrees well with WAIS Divide record on multi-decadal timescales. Combining all the available high-resolution records, we provide composite CO2 records for the last glacial termination and the Common Era. Causes of the abrupt CO2 changes will be discussed by comparison with other available paleoclimate records.

109

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Abrupt changes of atmospheric CO2 during the last glacial termination and the Common Era

Jinho Ahn1, Hunkyu Lee1, Christo Buizert2, Ed Brook2

1. Seoul National University 2. Oregon State University

Recent high-resolution ice core records from WAIS (West Antarctic Ice Sheet) Divide, Dome C and Law Dome ice cores show abrupt changes of atmospheric CO2 concentration at specific time intervals on decadal to centennial timescales. The abrupt features may help us better understand non-linear nature of carbon cycle feedbacks to climate changes and will be useful in improving predictions for future climate changes. However, the integrity of ice and analytical methods remain not entirely proved. In this context, analyses for multiple cores with a high-precision method should be accomplished to accurately constrain nature of the CO2 changes. Here we present new ice core results from Siple Dome and Styx ice cores, Antarctica that cover the last glacial deglaciation and the Common Era. Compared with existing records, 1-2% of CO2 concentration offsets are found among different Antarctic ice cores. However, magnitudes and speeds of the CO2 changes in WAIS Divide ice are relatively well confirmed: The Siple Dome record during the last glacial termination clearly shows abrupt increases of CO2 with a rate of 10 ppm per century. The Styx record during the Common Era agrees well with WAIS Divide record on multi-decadal timescales. Combining all the available high-resolution records, we provide composite CO2 records for the last glacial termination and the Common Era. Causes of the abrupt CO2 changes will be discussed by comparison with other available paleoclimate records.

P21


Introduction of Ganseong Global Climate Change Monitoring Station of Ministry of Environment, Korea

Taekyu Kim1, Kyoungbin Lee1, Miae Seong1, Jaehyun Lim1

1. Global Environment Research Division, Climate and Air Quality Research Department, National Institute of Environmental Research

One of the stations set up for measuring background atmosphere in Korea, is located in Ganseong, Gangwon Province, named the Global Climate Change Monitoring Station, operated by the Ministry of Environment, Korea. The monitoring station was originally set up in Gosan, Jeju Island, and operated from 2002 to 2011, but was moved to Ganseong located on the country's eastern coast in July 2011 due to its proximity to the Korea Meteorological Administration's monitoring station. The purpose of the station is to analyze trends and characteristics of the greenhouse gases such as carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O) and Chlorofluorocarbons (CFCs) in Korea. Meteorological variables (wind speed, wind direction, air temperature, humidity) and air pollution variables (SO2, CO, O3, NOx, NO, NO2, PM10) were also measured in this station. We analyzed the trends of greenhouse gases from 2012 to 2018 and the data was compared with the ones from home and abroad, which had been registered in WDCGG. The Ganseong station is meaningful in that it can give insight to distinguish the domestic source and foreign source of CO2 and CH4. It is necessary to keep an eye on greenhouse gases concentration in Ganseong station and do further examination on their sources and impacts.

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The Macquarie Island high precision CO2 record - Calculating uncertainties and exploring trends

Ann Stavert1, Ray Langenfelds1, Rachel Law1, Marcel van der Schoot1, Darren Spencer1, Paul Krummel1, Scott Chambers2, Alistair Williams2, Sylvester Werczynsk2, Roger Francey1, Russell Howden1

1. CSIRO 2. ANSTO

The Southern Ocean (south of 30° S) is a key global-scale sink of carbon dioxide (CO2). However, the isolated and inhospitable nature of this environment has restricted the number of oceanic and atmospheric CO2 measurements in this region. This has limited the scientific community's ability to investigate trends and seasonal variability of the sink. Compared to regions further north, the near-absence of terrestrial CO2 exchange and strong large-scale zonal mixing demands unusual inter-site measurement precision to help distinguish the presence of midlatitude to high latitude ocean exchange from large CO2 fluxes transported southwards in the atmosphere. Here we describe a continuous, in situ, ultra-high-precision Southern Ocean region CO2 record, which ran at Macquarie Island (54°37′ S, 158°52′ E) from 2005 to 2016 using a LoFlo2 instrument, along with its calibration strategy, uncertainty analysis and baseline filtering procedures. Uncertainty estimates calculated for minute and hourly frequency data range from 0.01 to 0.05 µmol mol−1 depending on the averaging period and application. Higher precisions are applicable when comparing Macquarie Island LoFlo measurements to those of similar instruments on the same internal laboratory calibration scale and more uncertain values are applicable when comparing to other networks. A comparison with flask records of atmospheric CO2 at Macquarie Island highlights the limitation of the flask record (due to corrections for storage time and limited temporal coverage) when compared to the new high-precision, continuous record: the new record shows much less noisy seasonal variations than the flask record. As such, this new record is ideal for improving our understanding of the spatial and temporal variability of the Southern Ocean CO2 flux, particularly when combined with data from similar instruments at other Southern Hemispheric locations. This presentation will explore the method used to calculate the uncertainties and trends and patterns in the uncertainties over time and with CO2 mole fraction.

111

P22


The Macquarie Island high precision CO2 record - Calculating uncertainties and exploring trends

Ann Stavert1, Ray Langenfelds1, Rachel Law1, Marcel van der Schoot1, Darren Spencer1, Paul Krummel1, Scott Chambers2, Alistair Williams2, Sylvester Werczynsk2, Roger Francey1, Russell Howden1

1. CSIRO 2. ANSTO

The Southern Ocean (south of 30° S) is a key global-scale sink of carbon dioxide (CO2). However, the isolated and inhospitable nature of this environment has restricted the number of oceanic and atmospheric CO2 measurements in this region. This has limited the scientific community's ability to investigate trends and seasonal variability of the sink. Compared to regions further north, the near-absence of terrestrial CO2 exchange and strong large-scale zonal mixing demands unusual inter-site measurement precision to help distinguish the presence of midlatitude to high latitude ocean exchange from large CO2 fluxes transported southwards in the atmosphere. Here we describe a continuous, in situ, ultra-high-precision Southern Ocean region CO2 record, which ran at Macquarie Island (54°37′ S, 158°52′ E) from 2005 to 2016 using a LoFlo2 instrument, along with its calibration strategy, uncertainty analysis and baseline filtering procedures. Uncertainty estimates calculated for minute and hourly frequency data range from 0.01 to 0.05 µmol mol−1 depending on the averaging period and application. Higher precisions are applicable when comparing Macquarie Island LoFlo measurements to those of similar instruments on the same internal laboratory calibration scale and more uncertain values are applicable when comparing to other networks. A comparison with flask records of atmospheric CO2 at Macquarie Island highlights the limitation of the flask record (due to corrections for storage time and limited temporal coverage) when compared to the new high-precision, continuous record: the new record shows much less noisy seasonal variations than the flask record. As such, this new record is ideal for improving our understanding of the spatial and temporal variability of the Southern Ocean CO2 flux, particularly when combined with data from similar instruments at other Southern Hemispheric locations. This presentation will explore the method used to calculate the uncertainties and trends and patterns in the uncertainties over time and with CO2 mole fraction.

P23


Development of Novel Trace Methane and Trace Carbon Dioxide Analyzers - Performance Evaluation Studies and Results of Field Deployment

Graham Leggett1, Kristen Minish1, Israel Begashaw1, Ryan Walbridge1, Derek Trutna1, Mark Johnson1, Anatoly Komissarov1

1. LI-COR

We report on the development, performance evaluation, and field deployment of recently commercially available trace gas analyzers for the measurement of atmospheric methane and carbon dioxide [1]. Based on Optical Feedback Cavity Enhanced Absorption Spectroscopy (OF-CEAS), the analyzers offer both the sensitivity and stability necessary for long-term atmospheric monitoring measurements, meeting the measurement compatibility goals as defined by WMO/GAW and other measurement networks. The first two analyzers released on this common platform are the LI-7810 CH4/CO2/H2O and LI-7815 CO2/H2O Trace Gas Analyzers. We introduce the now commercially available trace gas analyzers and implementation of the OF-CEAS technology. Performance characterization, including results from long-term measurement stability tests for methane and carbon dioxide at approximately atmospheric background concentration, is given. Allan deviation plots for measurements of methane and carbon dioxide, at similar concentrations, are also presented. In addition, we present data supporting stable operation from -25 degrees C to +45 degrees C, as well as an integrated water correction delivering dry mole fraction data. To make the LI-7810 and LI-7815 ready for laboratory deployment for atmospheric measurement applications, we worked in collaboration with GCWerks, resulting in a new version of the software tailored to these analyzers. We summarize how the software is used to manage data acquisition, instrument calibration, and system diagnostics. The introduction of the LI-7810 and LI-7815 analyzers also provides the sampling rate, response time, and dynamic range needed for multiple applications in mobile and agile deployment. Field results of a mobile area survey are presented, where the LI-7810 was installed in a car and driven to locations of interest to determine the presence of methane emissions. Potential sources included a landfill site, an anaerobic digester, and intensive agricultural operations. Open source tools were used to process concentration and geospatial data to visualize data using Google Earth. In conclusion, the work presented here has resulted in two commercially available trace gas analyzers, the LI-7810 and LI-7815 analyzers, for the measurement of methane and carbon dioxide. These portable and rugged instruments exceed requirements for both long-term atmospheric background measurements and offer a versatile platform for a range of mobile and agile measurements relevant to the better understanding of greenhouse gas emissions from anthropogenic and natural sources.

Reference

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[1] The initial principles and some portions of the new technology presented herein were developed in part based on the grant from the MONITOR Program by the U.S. Department of Energy Advanced Research Projects Agency - Energy (ARPA-E), under award number DE-AR0000537.

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[1] The initial principles and some portions of the new technology presented herein were developed in part based on the grant from the MONITOR Program by the U.S. Department of Energy Advanced Research Projects Agency - Energy (ARPA-E), under award number DE-AR0000537.

P24


Development of a new flask-air analysis system for the Global Greenhouse Gas Reference Network

Andrew Crotwell1,2, Edward Dlugokencky1, Patricia Lang1, Monica Madronich1,2, Eric Moglia1,2, Gabrielle Petron1,2, Kirk Thoning1

1. Global Monitoring Division, Earth System Research Laboratory, NOAA, Boulder CO 2. Cooperative Institute for Environmental Sciences, University of Colorado, Boulder CO

The Carbon Cycle Greenhouse Gases group (CCGG) of NOAA ESRL GMD monitors the major long-lived greenhouse gases (CO2, CH4, N2O, and SF6, along with CO and H2) by collecting discrete air samples (flask samples) from a global network of surface sites through its Global Greenhouse Gas Reference Network (GGGRN). In addition to the surface sites, the CCGG aircraft project collects flask-air samples by light aircraft to provide vertical profiles through the free troposphere. Air samples are returned to Boulder for analysis on a single analytical system to provide high internal consistency of the measurements. The current flask-air analysis system, which measures all six species simultaneously, has been in use since 1997 and has measured more than 300,000 discrete air samples. New analytical techniques based on laser spectroscopy have become commercially available that may lead to improvements in measurement uncertainty. However, these instruments are often developed for in situ applications where sample gas is unlimited. For flask-air samples, the amount of gas available is limited by the size of the sample collected and the needs of additional measurements performed on the flasks after the CCGG analysis. We describe here the development and testing of a new flask-air analysis system using laser spectroscopic techniques for CO2, CH4, N2O, and CO (along with gas chromatographic techniques for SF6 and H2) that minimizes gas usage while improving the analytical repeatability for CO2 (±0.02 μmol mol-1), CH4 (±0.1 nmol mol-1), and N2O (±0.03 nmol mol-1). The analytical performance for CO (±0.2 nmol mol-1), SF6 (±0.04 pmol mol-1), and H2 (±1.0 nmol mol-1) is the same as for the current system. Other improvements in consistency of sample/standard gas treatment, time of analysis, and efficiency of operation will be highlighted.

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Working standard gas saving system for in-situ CO2 and CH4 measurements and calculation method for concentrations and their uncertainty

Motoki Sasakawa1, Noritsugu Tsuda1, Toshinobu Machida1, Mikhail Arshinov2, Denis Davydov2, Alexander Fofonov2 1. CGER, National Institute for Environmental Studies 2. Institute of Atmospheric Optics, Russian Academy of Sciences, Siberian Branch, Russia

Delivering working standard gases to remote sites is a significant issue for long-term atmospheric observation. Thus, to reduce the consumption of the gases, Watai et al. [1] developed a system that utilizes on-site air as sub - working standard gas to track the baseline drift of an NDIR (Non-Dispersive Infrared) sensor. Watai et al. [1] then installed the system at a tower site at Berezorechka (56°08′45″N 84°19′55″E) in West Siberia in 2001 to measure CO2 concentrations semi-continuously. We added a semiconductor sensor for CH4 measurement [2] to the system, then expanded the tower observation network [3-5]. The tower network named JR-STATION (Japan-Russia Siberian Tall Tower Inland Observation Network) now consists of six towers in West Siberia. We further added a CRDS (Cavity Ring-Down Spectroscopy) at Karasevoe (58°14′44″N 82°25′28″E) in 2015 (Picarro G2401), and at Demyanskoe (59°47′29″N 70°52′16″E) and Noyabrsk (63°25′45″N 75°46′48″E) in 2016 (Picarro G2301) to renew the system. We reorganized the calculation method for the concentration to produce its uncertainty for each data at the same time. The uncertainty for CO2 varied in the same range as the previously estimated value (±0.3 ppm). On the other hand, the uncertainty for CH4 was often larger than the previously estimated value (±5 ppb) in an early study [3]. In this presentation, we will show the details of the modified measurement system and the calculation method. We will also present a comparison between the data produced with the NDIR (and the semiconductor sensor) and the CRDS data. The data was released until 2017 through our database (http://db.cger.nies.go.jp/portal/).

References

[1] Watai, T. et al., Atmos. Ocean. Tech. 27, 843-855, 2010.

[2] Suto, H. et al., J. Atmos. Ocean. Tech. 27, 1175-1184, 2010.

[3] Sasakawa, M. et al., Tellus 62B, 403-416, 2010.

[4] Sasakawa, M. et al., Tellus 64B, doi:10.3402/tellusb.v64i0.17514, 2012.

[5] Sasakawa, M. et al., J. Geophys. Res. 118, 1-10, doi:10.1002/jgrd.50755, 2013.

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P25


Working standard gas saving system for in-situ CO2 and CH4 measurements and calculation method for concentrations and their uncertainty

Motoki Sasakawa1, Noritsugu Tsuda1, Toshinobu Machida1, Mikhail Arshinov2, Denis Davydov2, Alexander Fofonov2 1. CGER, National Institute for Environmental Studies 2. Institute of Atmospheric Optics, Russian Academy of Sciences, Siberian Branch, Russia

Delivering working standard gases to remote sites is a significant issue for long-term atmospheric observation. Thus, to reduce the consumption of the gases, Watai et al. [1] developed a system that utilizes on-site air as sub - working standard gas to track the baseline drift of an NDIR (Non-Dispersive Infrared) sensor. Watai et al. [1] then installed the system at a tower site at Berezorechka (56°08′45″N 84°19′55″E) in West Siberia in 2001 to measure CO2 concentrations semi-continuously. We added a semiconductor sensor for CH4 measurement [2] to the system, then expanded the tower observation network [3-5]. The tower network named JR-STATION (Japan-Russia Siberian Tall Tower Inland Observation Network) now consists of six towers in West Siberia. We further added a CRDS (Cavity Ring-Down Spectroscopy) at Karasevoe (58°14′44″N 82°25′28″E) in 2015 (Picarro G2401), and at Demyanskoe (59°47′29″N 70°52′16″E) and Noyabrsk (63°25′45″N 75°46′48″E) in 2016 (Picarro G2301) to renew the system. We reorganized the calculation method for the concentration to produce its uncertainty for each data at the same time. The uncertainty for CO2 varied in the same range as the previously estimated value (±0.3 ppm). On the other hand, the uncertainty for CH4 was often larger than the previously estimated value (±5 ppb) in an early study [3]. In this presentation, we will show the details of the modified measurement system and the calculation method. We will also present a comparison between the data produced with the NDIR (and the semiconductor sensor) and the CRDS data. The data was released until 2017 through our database (http://db.cger.nies.go.jp/portal/).

References

[1] Watai, T. et al., Atmos. Ocean. Tech. 27, 843-855, 2010.

[2] Suto, H. et al., J. Atmos. Ocean. Tech. 27, 1175-1184, 2010.

[3] Sasakawa, M. et al., Tellus 62B, 403-416, 2010.

[4] Sasakawa, M. et al., Tellus 64B, doi:10.3402/tellusb.v64i0.17514, 2012.

[5] Sasakawa, M. et al., J. Geophys. Res. 118, 1-10, doi:10.1002/jgrd.50755, 2013.

P26


The ICOS automated flask sampler

Markus Eritt1, Richard Kneissl1, Martin Strube1, Lars Borchardt1, Armin Jordan1

1. ICOS-CAL / MPI-BGC Jena, Germany

An automated sampling device for the collection of discrete grab air samples in glass flasks for the later analysis in the central analytical laboratory (ICOS-CAL) is presented. The sample data is used for quality control for the in-situ measurements at class 1 stations in the ICOS network and to obtain additional supplementary information on the sample origin (O2/N2, δ13C, Δ14C) from the flask samples. The automated flask sampler developed and built at ICOS-CAL is capable of taking flask air samples under highly standardized conditions. Sampling event time schemes can be pre-programmed and communication with external devices (i.e. loggers) is possible. Sampling and sensor data is automatically stored and all necessary sampling related data can be automated transferred to the ICOS CAL. The sampler is controlled by an integrated computer opening a broad range of applications. The poster will give a overview of the sampler and its capabilities.

116

P27


Update on measurements of N2O and CO at the Cape Grim Baseline Air Pollution Station: commissioning of a new high precision in situ analyser E-A. Guerette1, Z. M. Loh1, P. B. Krummel1, R. L. Langenfelds1, D. A. Spencer1, J. Z. Ward2, N. Somerville2, S. Cleland2 1. CSIRO 2. Australian Bureau of Meteorology

Measurements of atmospheric nitrous oxide (N2O) and carbon monoxide (CO) at the Cape Grim Baseline Air Pollution Station have been made under the auspices of the Advanced Global Atmospheric Gases Experiment (AGAGE) since 1993, utilising a gas chromatography multi-detector system (GC-MD; electron capture (ECD) for N2O and reduction gas (RGA) for CO), which measures a single ambient aliquot once every 40 minutes. There is also a long record of measurements of these species from weekly/fortnightly flask samples collected under baseline conditions. Recently (March 2019), a new CO and N2O analyser based on mid-IR cavity ring-down spectroscopy (CRDS) (Picarro Inc., model G5310) was installed at Cape Grim to increase both measurement frequency and precision. Here we present an update on comparisons between the existing N2O and CO measurements at Cape Grim. We also present the initial CRDS N2O and CO timeseries and compare it to both the AGAGE GC-MD measurements and to the baseline flask record. We also share insights gained from tests performed on the analyser at our Aspendale laboratories before its deployment, and from the first ~6 months of operation at Cape Grim.

117

P27


Update on measurements of N2O and CO at the Cape Grim Baseline Air Pollution Station: commissioning of a new high precision in situ analyser E-A. Guerette1, Z. M. Loh1, P. B. Krummel1, R. L. Langenfelds1, D. A. Spencer1, J. Z. Ward2, N. Somerville2, S. Cleland2 1. CSIRO 2. Australian Bureau of Meteorology

Measurements of atmospheric nitrous oxide (N2O) and carbon monoxide (CO) at the Cape Grim Baseline Air Pollution Station have been made under the auspices of the Advanced Global Atmospheric Gases Experiment (AGAGE) since 1993, utilising a gas chromatography multi-detector system (GC-MD; electron capture (ECD) for N2O and reduction gas (RGA) for CO), which measures a single ambient aliquot once every 40 minutes. There is also a long record of measurements of these species from weekly/fortnightly flask samples collected under baseline conditions. Recently (March 2019), a new CO and N2O analyser based on mid-IR cavity ring-down spectroscopy (CRDS) (Picarro Inc., model G5310) was installed at Cape Grim to increase both measurement frequency and precision. Here we present an update on comparisons between the existing N2O and CO measurements at Cape Grim. We also present the initial CRDS N2O and CO timeseries and compare it to both the AGAGE GC-MD measurements and to the baseline flask record. We also share insights gained from tests performed on the analyser at our Aspendale laboratories before its deployment, and from the first ~6 months of operation at Cape Grim.

P28


Performance analysis of Spatial Heterodyne Spectroscopy on column-averaged carbon dioxide observation

Ye Hanhan1, Wang Xianhua1, Xiong Wei1, Shi Hailiang1, Li Zhiwei1

1. Hefei institutes of Physical Science, Chinese Academy of Sciences

Carbon Dioxide (CO2) is the most important greenhouse gas in the atmosphere and plays an important role in global climate, accurate knowledge about atmospheric concentration and variability of CO2 is a foundation for study on climate change. Since relative small variation on CO2 column-averaged concentration, Spatial Heterodyne Spectrometer (SHS) measuring CO2 absorption band spectrum at 1580nm with high spectral resolution sensitive to small variation has been designed and constructed. In this paper, the theory and instrument characterization of SHS were introduced briefly, the retrieval algorithm for column-averaged CO2 was described, and the performance of SHS was analyzed through simulation study, together with results of on-ground and in-flight engineering test. The measurements show clear CO2 absorption lines and expected sensitivity, and a good agreement was found between the retrievals and GOSAT CO2 products. The results show that the ability of spatial heterodyne spectroscopy for column-averaged CO2 is validated.

118

P29


Contrasting the differences in CO2 atmospheric growth over Korea with global patterns

Lev Labzovskii1, Samuel Takele Kenea1, Tae-Young Goo1, Jinwon Kim1, Haeyoung Lee1, Shanlan Li1, Young-Suk Oh1, Young-Hwa Byun1

1. National Institute of Meteorological Sciences

Increase of atmospheric CO2 fraction is the main driver of the global climate warming and the subject of a wide range of climate mitigation policies. This increase currently equals to ~1 ppm and mainly driven by the effects of El-Nino Southern Oscillation and by anthropogenic emissions. The problem is that the local drivers of atmospheric CO2 interannual variability (IAV) are less understood at local scales outside the tropics. This work is therefore dedicated to the short-term investigation of contrasts in IAV of XCO2 between Korea and the entire world. To this end, we use XCO2 output from CarbonTracker-Asia (CTA) and Copernicus Atmospheric Monitoring Service (CAMS) systems in 2005-2015 years and further compare the results with the most recent estimates on IAV of XCO2 from Global Carbon Budget-2018 and the composites of spaceborne XCO2 observations. We show that IAV of XCO2 is always higher over Korea compared to global scales (in 2005-2015) and this difference is significant in 70% (CAMS) and 90% (CTA) of cases. The main drivers of contrasted CO2 growth over Korea (compared to the globe) are Net Primary Productivity (NPP) of ecosystem and the temperature variations that were observed a year before the growth is observed (the role of anthropogenic emissions is minor). Spatial correlation analysis revealed that the contrasting IAV of XCO2 over Korea can be predicted for both CAMS and CTA using the NPP and temperature estimates at 0.5 x 0.5 degree resolution. For CAMS, the temperature changes exhibit high agreement (R > 0.70) with positive shifts in IAV of XCO2 over Korea during the next year for 60% of the Korean territory while the role of NPP is slightly lower (R = 0.60-0.70) and applicable for 10% of Korean territory. For CTA both temperature and NPP changes exert lower but reasonable agreement with positive shifts in IAV of XCO2 over Korea during the next year (R > 0.60) nearly ~40% of Korean territory. High predictability of changes using NPP and temperature of previous year is evidenced in the northern part of peninsula precisely over the area covered by the broadleaf deciduous trees that are more tolerant to excessive temperature events from productivity standpoint.

119

P29


Contrasting the differences in CO2 atmospheric growth over Korea with global patterns

Lev Labzovskii1, Samuel Takele Kenea1, Tae-Young Goo1, Jinwon Kim1, Haeyoung Lee1, Shanlan Li1, Young-Suk Oh1, Young-Hwa Byun1

1. National Institute of Meteorological Sciences

Increase of atmospheric CO2 fraction is the main driver of the global climate warming and the subject of a wide range of climate mitigation policies. This increase currently equals to ~1 ppm and mainly driven by the effects of El-Nino Southern Oscillation and by anthropogenic emissions. The problem is that the local drivers of atmospheric CO2 interannual variability (IAV) are less understood at local scales outside the tropics. This work is therefore dedicated to the short-term investigation of contrasts in IAV of XCO2 between Korea and the entire world. To this end, we use XCO2 output from CarbonTracker-Asia (CTA) and Copernicus Atmospheric Monitoring Service (CAMS) systems in 2005-2015 years and further compare the results with the most recent estimates on IAV of XCO2 from Global Carbon Budget-2018 and the composites of spaceborne XCO2 observations. We show that IAV of XCO2 is always higher over Korea compared to global scales (in 2005-2015) and this difference is significant in 70% (CAMS) and 90% (CTA) of cases. The main drivers of contrasted CO2 growth over Korea (compared to the globe) are Net Primary Productivity (NPP) of ecosystem and the temperature variations that were observed a year before the growth is observed (the role of anthropogenic emissions is minor). Spatial correlation analysis revealed that the contrasting IAV of XCO2 over Korea can be predicted for both CAMS and CTA using the NPP and temperature estimates at 0.5 x 0.5 degree resolution. For CAMS, the temperature changes exhibit high agreement (R > 0.70) with positive shifts in IAV of XCO2 over Korea during the next year for 60% of the Korean territory while the role of NPP is slightly lower (R = 0.60-0.70) and applicable for 10% of Korean territory. For CTA both temperature and NPP changes exert lower but reasonable agreement with positive shifts in IAV of XCO2 over Korea during the next year (R > 0.60) nearly ~40% of Korean territory. High predictability of changes using NPP and temperature of previous year is evidenced in the northern part of peninsula precisely over the area covered by the broadleaf deciduous trees that are more tolerant to excessive temperature events from productivity standpoint.

P30


Quality analysis of on-orbit observation data of Greenhouse gases Monitoring Instrument on GaoFeng-5 satellite

Hailiang Shi1, Wei Xiong1, Zhiwei Li1, Haiyan Luo1


Greenhouse gases Monitoring Instrument (GMI) is the first greenhouse gas satellite payload based on the spatial heterodyne spectroscopy (SHS) in the world. It was successfully launched on May 28, 2018. In this paper, the quality of on-orbit observation data acquired after the start of GMI is analyzed. The interferograms of each spectral channel are compared with ground test data, and the zero optical path difference (ZPD)and interferometric modulation (IM) are analyzed. Using the GMI ground data processing system, spectral reconstruction and calibration coefficient loading of interferogram were carried out, and the spectrum were compared with the theoretical simulation spectrum and the GOSAT measured spectrum respectively. In addition, the spectral and radiation stability of greenhouse gases at different times were analyzed. Through the analysis of GMI on-orbit observation data, it shows that GMI payload spectral resolution, signal-to-noise ratio, detection sensitivity, spectral stability, radiation stability and other indicators have met the theoretical design requirements, and the overall performance has reached the international advanced level, laying the foundation for the next production of high-precision greenhouse gas data products.

120

P31


Observing patterns of CO2 and air pollutants of cities using satellite data

Hayoung Park1, Su-Jong Jeong1


Cities account for more than 70% of the global CO2 emissions and are a major source of air pollutants which impact the environment, air quality, and climate change. This study aims to observe the patterns of CO2 and air pollutants CO and NO2 of cities across the world using satellite data. We use satellite data from the Orbiting Carbon Observatory-2 (OCO-2) for CO2 and the Sentinel-5 Precursor (S5P) Tropospheric Monitoring Instrument (TROPOMI) for air pollutants CO and NO2. We observe the concentrations of CO2 and calculate the urban CO2 enhancements (ΔCO2) over more than 50 cities. Since CO and NO2 are often co-emitted with CO2 during anthropogenic combustion, we go on to observe the relationships of CO2 and air pollutants CO and NO2 over the selected cities of the study. Our analyses show that globally, CO2 and air pollutants CO and NO2 show a linear pattern. On a regional scale, cities show different ratios of CO2 and air pollutants according to their different emission characteristics and policies.

121

P31


Observing patterns of CO2 and air pollutants of cities using satellite data

Hayoung Park1, Su-Jong Jeong1


Cities account for more than 70% of the global CO2 emissions and are a major source of air pollutants which impact the environment, air quality, and climate change. This study aims to observe the patterns of CO2 and air pollutants CO and NO2 of cities across the world using satellite data. We use satellite data from the Orbiting Carbon Observatory-2 (OCO-2) for CO2 and the Sentinel-5 Precursor (S5P) Tropospheric Monitoring Instrument (TROPOMI) for air pollutants CO and NO2. We observe the concentrations of CO2 and calculate the urban CO2 enhancements (ΔCO2) over more than 50 cities. Since CO and NO2 are often co-emitted with CO2 during anthropogenic combustion, we go on to observe the relationships of CO2 and air pollutants CO and NO2 over the selected cities of the study. Our analyses show that globally, CO2 and air pollutants CO and NO2 show a linear pattern. On a regional scale, cities show different ratios of CO2 and air pollutants according to their different emission characteristics and policies.

P32


14CO2 observations in atmospheric CO2 at Anmyeondo GAW station, Korea:implication for fossil fuel CO2 and emission ratios

Haeyoung Lee1,2, Edward J. Dlugokencky3, Jocelyn C. Turnbull4, Scott J. Lehman5, John Miller3, Jeongsik Lim6, Sepyo Lee1, Gangwoong Lee2, Sang-Sam Lee1, Sang-Boom Ryoo1 1 KMA/NIMS 2 Hankuk University of Foreign Studies 3.National Atmosphere and Ocean Administration 4.National Isotope Center, GNS 5.INSTAAR, University of Colorado 6Korea Research Institute of Standard and Science

Korea is a rapidly developing country with fast economic growth, and it is also located next to China, which is the world’s largest emitter of anthropogenic CO2. To quantify Korea’s CO2 emissions, it is important to understand CO2 emissions and sinks for the surrounding region. For this presentation, we used flask-air samples collected from a 40 m tower during May 2014 to August 2016 at Anmyeondo (AMY, 36.53° N, 126.32°E; 46 m a.s.l) Global Atmosphere Watch (GAW) station, located in the western part of Korea, for analysis of 14CO2 as a fossil fuel CO2 tracer. 70 flask-air pairs were collected and analysed at NOAA/ESRL for CO2, CH4, N2O, SF6 and for △14C by INSTARR. △14CO2 at AMY varied from -59.5±1.8‰ (1σ) to 23.1±1.8‰ and its mean value was -6.2±18.8‰ during the experiment period. The contribution to atmospheric CO2 from fossil fuel combustion at AMY (CO2_ff) ranged between -0.05 and 32.7 ppm, with an average was 9.7±7.8 ppm (1 σ). Large CO2_ff enhancements were observed regardless of season. When compared to the 4.4±5.4 ppm CO2_ff found by Turnbull et al. (2011) for 2004 to 2010, these new values were nearly double. CO2_ff in outflow from China also increased to 13.4±8.2 ppm from 6.7 ±10.5 ppm for 2009 to 2010. For CO2_bio, there is a strong seasonal cycle with the lowest values from July to September since photosynthetic drawdown is expected to be strong in summer with a mean value of 0.9±5.8 ppm. We also implemented a cluster analysis using HYSPLIT backward to study the influence of air mass transport. Based on clusters of trajectories from specific regions, trace gas enhancement: CO2_ff ratio and correlation coefficients were analyzed to determine potential of alternative proxies to △14C. For CO: CO2_ff, observed values during outflow from the Asian continent were greater (from 24.28 ±4.79 to 34.89±4.83) than in Korea Local air (7.28±0.43). Korea Local samples were similar to inventories (7.33 in 2012, EDGARv4.3.2) while air masses originating in China were greater than the inventory (20.98 in 2012).

122

P33


Distinguishing Artifacts from Real Variability in Airborne Measurements of δ(Ar/N2)

Eric Morgan1, Britt Stephens2, Benni Birner1, Ralph Keeling1

1. Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, USA 2. National Center for Atmospheric Research, Boulder, CO, USA

Atmospheric oxygen, δ(O2/N2), is an important carbon cycle tracer. Measurements of δ(O2/N2) with isotope ratio mass spectrometry (IRMS) allow for the argon to nitrogren ratio, δ(Ar/N2), to also be quantified. This raises the possibility to correct δ(O2/N2) data with δ(Ar/N2) for fractionation artifacts, if the mechanism is known. To correct for fractionation, however, it is necessary to consider the real sources of variability in δ(Ar/N2), which are primarily air-sea gas exchange for tropospheric samples and gravitational fractionation for stratospheric samples. Airborne data from several global campaigns show scatter in δ(Ar/N2) which is larger than expected, as inferred from surface data. We find that this variability of observed δ(Ar/N2) is about 2-5 times greater than we would expect in the lower troposphere. Some of this scatter is due to mass-dependent fractionation at the sampling inlet. We have tested two sample inlet designs, a fin-shaped inlet and a diffusing inlet, and find that the fin shape fractionates δ(Ar/N2) approximately +20 per meg in lower troposphere, with an altitude dependence that increases this to a maximum of +34 per meg at 7-8 km. Additional sources of scatter appear to be related to thermal fractionation and/or mass-dependent fractionation, but are not likely to be acquired during flask storage, as no relationship exists between δ(Ar/N2) and storage time. Finally, we discuss various correction schemes for airborne δ(O2/N2) data based on δ(Ar/N2), and their impacts on the interpretation of observed variability.

123

P33


Distinguishing Artifacts from Real Variability in Airborne Measurements of δ(Ar/N2)

Eric Morgan1, Britt Stephens2, Benni Birner1, Ralph Keeling1

1. Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, USA 2. National Center for Atmospheric Research, Boulder, CO, USA

Atmospheric oxygen, δ(O2/N2), is an important carbon cycle tracer. Measurements of δ(O2/N2) with isotope ratio mass spectrometry (IRMS) allow for the argon to nitrogren ratio, δ(Ar/N2), to also be quantified. This raises the possibility to correct δ(O2/N2) data with δ(Ar/N2) for fractionation artifacts, if the mechanism is known. To correct for fractionation, however, it is necessary to consider the real sources of variability in δ(Ar/N2), which are primarily air-sea gas exchange for tropospheric samples and gravitational fractionation for stratospheric samples. Airborne data from several global campaigns show scatter in δ(Ar/N2) which is larger than expected, as inferred from surface data. We find that this variability of observed δ(Ar/N2) is about 2-5 times greater than we would expect in the lower troposphere. Some of this scatter is due to mass-dependent fractionation at the sampling inlet. We have tested two sample inlet designs, a fin-shaped inlet and a diffusing inlet, and find that the fin shape fractionates δ(Ar/N2) approximately +20 per meg in lower troposphere, with an altitude dependence that increases this to a maximum of +34 per meg at 7-8 km. Additional sources of scatter appear to be related to thermal fractionation and/or mass-dependent fractionation, but are not likely to be acquired during flask storage, as no relationship exists between δ(Ar/N2) and storage time. Finally, we discuss various correction schemes for airborne δ(O2/N2) data based on δ(Ar/N2), and their impacts on the interpretation of observed variability.

P34


Trend in atmospheric CO2 concentrations and carbon isotopic compositions observed at a regional background site in East Asia

Hyeri Park1, Mi-Kyung Park1, Sunyoung Park1

1. Kyungpook Institute of Oceanography, Kyungpook National University, Daegu 41566, Republic of Korea / Department of Oceanography, Kyungpook National University, Daegu 41566, Republic of Korea

Increase of atmospheric CO2 is anthropogenic, but seasonal and diurnal variability dominating individual observations is caused by the terrestrial biosphere. Therefore, to estimate the fossil fuel contributions to local atmospheric observations of CO2, radiocarbon (14C) of atmospheric CO2 is an ideal tracer since fossil fuel-derived CO2 is free of 14C while all other significant sources have 14C content similar to that of the atmosphere. In this study, we present 11-year observations of atmospheric CO2 concentration, and corresponding stable carbon isotopic composition of atmospheric CO2 (δ13C-CO2) obtained on a weekly basis at Gosan station (Jeju Island, Korea; 33oN, 126oE, 72m above sea level) from 2001 to 2011. The radiocarbon isotope compositions (Δ14C-CO2) were also analyzed in 2001 and 2011. The time series have shown that the observed CO2 concentrations at Gosan have increased by 23.0±1.5 ppm from 2001 to 2011, which corresponds to the decrease of δ13C of -0.30±0.02 ‰ and Δ14C decrease of -50.9±9.4 ‰. The variations for atmospheric CO2 concentrations, δ13C and Δ14C were similar to those from other background stations during the same time period in the northern hemisphere. The derived ratio between Δ14C decrease vs. CO2 increase was -2.2±0.9 ‰/ppm which is in agreement with ~2.8 ‰ of Δ14C depletion, occurring when 14C-depleted fossil fuel-derived 1 ppm CO2 was added atmospheric CO2 of 380 ppm [1]. The weekly concentration data were further analyzed to identify regional background data and pollution events, in comparison with the high-frequency in-situ measurement of CO2 concentrations made from 2009 to 2011. Δ14C values representing pollution events at Gosan were identified by separated background and pollution data. Atmospheric CO2 pollution enhancement by 1 ppm at Gosan in 2011 was corresponding to -1.9±1.3 ‰ of reduction in Δ14C. This is consistent with the observed 11-year changes of CO2 concentrations and Δ14C-CO2. Therefore, we confirm that the observed increase in atmospheric CO2 concentrations for the 11 years at Gosan can be explained by the influence of fossil fuel burnings.

Reference

[1] Turnbull, J. C., Miller, J. B., Lehman, S. J., Tans, P. P., Sparks, R. J., & Southon, J. (2006). Comparison of 14CO2, CO, and SF6 as tracers for recently added fossil fuel CO2 in the atmosphere and implications for biological CO2 exchange. Geophysical research letters, 33(1).

124

P35


European atmospheric 14CO2 activities within the ICOS RI network Samuel Hammer1, Sebastian Conil2, Marc Delmotte3, Juha Hatakka4, Michal Heliasz5, Arjan Hensen6, Dagmar Kubistin7, Matthias Lindauer7, Mikaell Ottosson-Löfvenius8, Meelis Mölder9, Michiel Ramonet3, Gerard Spain10, Martin Steinbacher11, Garbiela Vítková12, Ingeborg Levin13 1. ICOS Central Radiocarbon Laboratory, Heidelberg University, 69120 Heidelberg, Germany 2. Direction Recherche & Développement, Andra, CMHM, RD960, 55290 Bure France 3. Laboratoire des Sciences du Climat et de l'Environnement (LSCE), CEA - Orme des Merisiers 91191 Gif sur Yvette, France 4. Climate Research Programme, Finnish Meteorological Institute, Helsinki, Finland 5. Center for Environmental and Climate Research, Lund University, Sölvegatan 12, SE-22362, Lund, Sweden 6. Energy research Centre of the Netherlands (ECN), Petten, the Netherlands 7. German Meteorological Service, Meteorological Observatory Hohenpeissenberg, Germany 8. Dept. of forest ecology and management, Swedish university of agricultural sciences, Sweden 9. Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden 10. National University of Ireland Galway, Galway, Ireland 11. Empa, Laboratory for Air Pollution/Environmental Technology, Duebendorf, Switzerland 12. Global Change Research Institute, Czech Academy of Sciences, Brno, Czech Republic 13. Institut für Umweltphysik, Heidelberg University, Heidelberg, Germany

Radiocarbon in atmospheric CO2 (14C) has successfully proven to be a very powerful tracer for carbon cycle studies and for quantifying atmospheric CO2 originating from the combustion of fossil fuels. The European Integrated Carbon Observation System (ICOS) research infrastructure (ICOS-RI.eu) has thus selected 14CO2 as one of the mandatory parameters to be sampled at all atmospheric ICOS Class 1 stations. Class 1 stations are committed to the most ambitious set of parameters. The samples are subsequently analysed at the ICOS Central Radiocarbon Laboratory. ICOS follows a two-pronged sampling strategy for 14CO2. On the one hand, flask samples will be collected as spot samples during predefined conditions; on the other hand, continuous, two-weekly integrated samples are collected to estimate long-term trends of fossil fuel CO2 at the sites. We present updated results of ICOS integrated 14CO2 samples from 12 European stations, starting in 2015. These measurements provide an overview of the current 14CO2 levels at predominantly background stations but also illustrate the influence from regional fossil fuel sources or nuclear emissions visible at some of the ICOS stations.

125

P35


European atmospheric 14CO2 activities within the ICOS RI network Samuel Hammer1, Sebastian Conil2, Marc Delmotte3, Juha Hatakka4, Michal Heliasz5, Arjan Hensen6, Dagmar Kubistin7, Matthias Lindauer7, Mikaell Ottosson-Löfvenius8, Meelis Mölder9, Michiel Ramonet3, Gerard Spain10, Martin Steinbacher11, Garbiela Vítková12, Ingeborg Levin13 1. ICOS Central Radiocarbon Laboratory, Heidelberg University, 69120 Heidelberg, Germany 2. Direction Recherche & Développement, Andra, CMHM, RD960, 55290 Bure France 3. Laboratoire des Sciences du Climat et de l'Environnement (LSCE), CEA - Orme des Merisiers 91191 Gif sur Yvette, France 4. Climate Research Programme, Finnish Meteorological Institute, Helsinki, Finland 5. Center for Environmental and Climate Research, Lund University, Sölvegatan 12, SE-22362, Lund, Sweden 6. Energy research Centre of the Netherlands (ECN), Petten, the Netherlands 7. German Meteorological Service, Meteorological Observatory Hohenpeissenberg, Germany 8. Dept. of forest ecology and management, Swedish university of agricultural sciences, Sweden 9. Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden 10. National University of Ireland Galway, Galway, Ireland 11. Empa, Laboratory for Air Pollution/Environmental Technology, Duebendorf, Switzerland 12. Global Change Research Institute, Czech Academy of Sciences, Brno, Czech Republic 13. Institut für Umweltphysik, Heidelberg University, Heidelberg, Germany

Radiocarbon in atmospheric CO2 (14C) has successfully proven to be a very powerful tracer for carbon cycle studies and for quantifying atmospheric CO2 originating from the combustion of fossil fuels. The European Integrated Carbon Observation System (ICOS) research infrastructure (ICOS-RI.eu) has thus selected 14CO2 as one of the mandatory parameters to be sampled at all atmospheric ICOS Class 1 stations. Class 1 stations are committed to the most ambitious set of parameters. The samples are subsequently analysed at the ICOS Central Radiocarbon Laboratory. ICOS follows a two-pronged sampling strategy for 14CO2. On the one hand, flask samples will be collected as spot samples during predefined conditions; on the other hand, continuous, two-weekly integrated samples are collected to estimate long-term trends of fossil fuel CO2 at the sites. We present updated results of ICOS integrated 14CO2 samples from 12 European stations, starting in 2015. These measurements provide an overview of the current 14CO2 levels at predominantly background stations but also illustrate the influence from regional fossil fuel sources or nuclear emissions visible at some of the ICOS stations.

P36


Five years of δ13C(CO2) measurements from an in situ Fourier transform infrared trace gas and isotope analyser at Lauder, New Zealand

Dan Smale1, David Griffith2, Rowena Moss1, Gordon Brailsford1

1. NIWA, New Zealand 2. School of Chemistry & Centre for Atmospheric Chemistry, University of Wollongong, Australia

We present a five year time series (2014 - 2018) of in situ δ13C(CO2) measurements made at the NIWA Lauder atmospheric research station using a Fourier transform infrared trace gas and isotope analyser. Individual isotopologue measurements of CO2 (12CO2, 13CO2 and CO18O) are calibrated (instead of a ratio-based calibration approach) using the methodology set out in Griffith, AMT, 2018. We assess the long-term performance of the analyser and compare the calibrated measurements to that of collocated δ13C(CO2) flask samples.

126

P37


The effect of phosphoric acid on carbon dioxide standard gas evolution

Jun Sonobe1, Megumi Isaji1, Tracey Jacksier2, Rick Socki2, Rie Sato3

1. Air Liquide Laboratories 2. American Air Liquide 3. Shoko Science

Stable isotope scales are artifact-based. That is, they are dependent on established reference materials (RMs) with assigned values for both the definition and the scale realization; their primary RMs are not SI traceable. The primary RM NBS19, composed of marble carbonate (defined values δ13C: +1.95‰, δ18O: -2.20‰, VPDB). formerly recognized by IUPAC for the definition and realization of the VPDB δ13C and δ18O scale, is now exhausted. Marble carbonates are useful reference materials because they have been shown to be isotopically stable over time. A new marble carbonate, IAEA-603, (δ13C: +2.46 ± 0.01‰, δ18O: -2.37‰ ± 0.04‰, VPDB), released in 2016, has replaced NBS19. IAEA-603 is currently recommended to be used as the primary RM to realize the VPDB scale. All air sample measurements are performed against CO2 extracted from air mixtures, usually in cylinders. Regular recalibration and correction for drift, if found, are essential for proper laboratory practice. Of critical importance is the presence of moisture in air, as oxygen isotope exchange between CO2 and H2O during sample storage can potentially change the δ18O composition of that CO2. This issue can be addressed by careful flask pre-treatment and employing air sample drying techniques. In order to improve CO2 stable isotope measurement, GGMT 2017 requests that IAEA continues to develop the capability to evolve CO2 from carbonates by H3PO4 acidic reaction as follows.

CaCO3 + H3PO4 → CO2 + CaHPO4 + H2O

By using the above reaction to release CO2 from primary RMs and creating CO2-in-air mixtures for testing purpose, the IAEA can validate the JRAS-06 scale. As a test of this validation process, phosphoric acid manufactured by various suppliers was used as a means of understanding which factors influence CO2, C and O isotope ratios during acid dissolution of IAEA-603 and CO-1, respectively. δ13C and δ18O of CO2 evolved by these different acid suppliers were compared with standard value defined by published results of IAEA-603 and CO-1. Furthermore, an alternative solution is proposed to improve the reliability of carbon and oxygen isotope analyses.

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The effect of phosphoric acid on carbon dioxide standard gas evolution

Jun Sonobe1, Megumi Isaji1, Tracey Jacksier2, Rick Socki2, Rie Sato3

1. Air Liquide Laboratories 2. American Air Liquide 3. Shoko Science

Stable isotope scales are artifact-based. That is, they are dependent on established reference materials (RMs) with assigned values for both the definition and the scale realization; their primary RMs are not SI traceable. The primary RM NBS19, composed of marble carbonate (defined values δ13C: +1.95‰, δ18O: -2.20‰, VPDB). formerly recognized by IUPAC for the definition and realization of the VPDB δ13C and δ18O scale, is now exhausted. Marble carbonates are useful reference materials because they have been shown to be isotopically stable over time. A new marble carbonate, IAEA-603, (δ13C: +2.46 ± 0.01‰, δ18O: -2.37‰ ± 0.04‰, VPDB), released in 2016, has replaced NBS19. IAEA-603 is currently recommended to be used as the primary RM to realize the VPDB scale. All air sample measurements are performed against CO2 extracted from air mixtures, usually in cylinders. Regular recalibration and correction for drift, if found, are essential for proper laboratory practice. Of critical importance is the presence of moisture in air, as oxygen isotope exchange between CO2 and H2O during sample storage can potentially change the δ18O composition of that CO2. This issue can be addressed by careful flask pre-treatment and employing air sample drying techniques. In order to improve CO2 stable isotope measurement, GGMT 2017 requests that IAEA continues to develop the capability to evolve CO2 from carbonates by H3PO4 acidic reaction as follows.

CaCO3 + H3PO4 → CO2 + CaHPO4 + H2O

By using the above reaction to release CO2 from primary RMs and creating CO2-in-air mixtures for testing purpose, the IAEA can validate the JRAS-06 scale. As a test of this validation process, phosphoric acid manufactured by various suppliers was used as a means of understanding which factors influence CO2, C and O isotope ratios during acid dissolution of IAEA-603 and CO-1, respectively. δ13C and δ18O of CO2 evolved by these different acid suppliers were compared with standard value defined by published results of IAEA-603 and CO-1. Furthermore, an alternative solution is proposed to improve the reliability of carbon and oxygen isotope analyses.

P38


Assessment of an Isotope Ratio Infrared Spectrometer to measure isotope ratios of carbon dioxide in air under laboratory conditions and at Baring Head, New Zealand

Peter Sperlich1, Rowena Moss1, Gordon Brailsford1, John McGregor1, Sylvia Nichol1, Sara Mikaloff Fletcher1, Magda Mandic2, C. Ian Schipper3, Paul Krummel4, Zoe Loh4, Ray Langenfels4

1. National Institute of Water and Atmospheric Research (NIWA), Wellington, New Zealand 2. Thermo Fisher Scientific, Bremen, Germany 3. Victoria University of Wellington, New Zealand 4. Commonwealth Scientific and Industrial Research Organisation (CSIRO), Aspendale, Australia

NIWA’s program for observations of isotope ratios in atmospheric carbon dioxide is currently based on flask measurements, generating about 130-140 measurements per year from stations in New Zealand and Antarctica. A range of in-situ analysers are now available that enable observations with much higher temporal resolution. One important question is how the data quality of such new analytical technologies compares with that of the traditional isotope ratio mass spectrometry (IRMS) -based methods. In this study, we explore the performance of the Thermo Scientific™ Delta Ray™ Isotope Ratio Infrared Spectrometer (IRIS), which measures carbon and oxygen isotope ratios as well as carbon mole fractions of atmospheric CO2. We performed a range of experiments with the Delta Ray IRIS in our atmospheric laboratory, including stability tests, matrix air effects (variations in N2/O2/Ar of the air) and measurements in flask samples. The instrument was also deployed at our observatory at Baring Head, New Zealand, over a 26-day trial period. We show the resolution of a Delta Ray in an environment with minimal variability in the measured parameters and compare its performance to that of well-established systems to measure mixing- and isotope ratios in air.

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Development of a Quality Assurance Scheme for stable isotope measurements in agreement with the GAW Quality Assurance Principles



A key component of the Global Atmospheric Watch (GAW) Quality Assurance Scheme (QAS) [1] for each greenhouse gas (GHG) is establishing and then reaching appropriate data quality objectives (DQOs). As DQOs are to be used “as the basis for establishing the quality and quantity of data needed to support decisions” (p22 in [1]) they include, but are not limited to, quantities describing measurement uncertainty and/or network compatibility. However, data compatibility targets (as components of DQOs) for stable isotope data of atmospheric CO2 and methane (established at 0.01 ‰ and 0.02 ‰ for δ13C of air-CO2 and air-methane [1]) have not been demonstrated, either on real air samples or on round-robin air cylinders [1, 2]. Many QAS elements in the area of stable isotopes are missing or not well developed; these elements include a World/Regional Calibration Centre (WCC/RCC), standard operating procedures (SOPs), recommendations on calibration transfer, measurements, instrumental tests, data treatment and uncertainty propagation, and audits. For example, discrepancies have been observed on methane isotope data that can be clustered into several groups, including a broken calibration traceability with no update of values for reference materials in use, and non-synchronised raw data treatment and instrumental corrections [2]. In this respect, the revised, hierarchical scheme of international reference materials (RMs) aimed at the sustainable, with the lowest possible uncertainty, realisation of the VPDB scale (all RMs are traceable to the primary RM on this artefact-based scale, as described in a companion presentation) is only a part of the QAS for stable isotopes. This poster presents and discusses various aspects of a QAS being developed for stable isotope measurements that is in agreement with the GAW Quality Assurance Principles and identifies the important roles that the “missing” elements play. Such a QAS is becoming more critical with the increased use of optical isotope analysers deployed in continuous mode for regional studies, used in parallel with stable isotope ratio mass-spectrometry, where analytical principles and the components of measurement uncertainty are very different for the two techniques.

References

[1] GAW implementation Plan 2016-2023, GAW report 228

[2] GGMT-2017, GAW Report 242.

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Development of a Quality Assurance Scheme for stable isotope measurements in agreement with the GAW Quality Assurance Principles



A key component of the Global Atmospheric Watch (GAW) Quality Assurance Scheme (QAS) [1] for each greenhouse gas (GHG) is establishing and then reaching appropriate data quality objectives (DQOs). As DQOs are to be used “as the basis for establishing the quality and quantity of data needed to support decisions” (p22 in [1]) they include, but are not limited to, quantities describing measurement uncertainty and/or network compatibility. However, data compatibility targets (as components of DQOs) for stable isotope data of atmospheric CO2 and methane (established at 0.01 ‰ and 0.02 ‰ for δ13C of air-CO2 and air-methane [1]) have not been demonstrated, either on real air samples or on round-robin air cylinders [1, 2]. Many QAS elements in the area of stable isotopes are missing or not well developed; these elements include a World/Regional Calibration Centre (WCC/RCC), standard operating procedures (SOPs), recommendations on calibration transfer, measurements, instrumental tests, data treatment and uncertainty propagation, and audits. For example, discrepancies have been observed on methane isotope data that can be clustered into several groups, including a broken calibration traceability with no update of values for reference materials in use, and non-synchronised raw data treatment and instrumental corrections [2]. In this respect, the revised, hierarchical scheme of international reference materials (RMs) aimed at the sustainable, with the lowest possible uncertainty, realisation of the VPDB scale (all RMs are traceable to the primary RM on this artefact-based scale, as described in a companion presentation) is only a part of the QAS for stable isotopes. This poster presents and discusses various aspects of a QAS being developed for stable isotope measurements that is in agreement with the GAW Quality Assurance Principles and identifies the important roles that the “missing” elements play. Such a QAS is becoming more critical with the increased use of optical isotope analysers deployed in continuous mode for regional studies, used in parallel with stable isotope ratio mass-spectrometry, where analytical principles and the components of measurement uncertainty are very different for the two techniques.

References

[1] GAW implementation Plan 2016-2023, GAW report 228

[2] GGMT-2017, GAW Report 242.

P40


Characterisation of optical isotope analysers for carbon dioxide in the framework of EMPIR project SIRS

Ivan Prokhorov1, Gang Li1, Olav Werhahn1, Volker Ebert1, Farilde Steur2, Harro Meijer2, Francesca Rolle3, Tuomas Poikonen4, Jan Petersen5, David Balslev-Harder5, Joachim Mohn6

1. Physikalisch-Technische Bundesanstalt (PTB), Braunschweig, Germany 2. Centre for Isotope Research (CIO), University of Groningen, Groningen, Netherlands 3. Istituto Nazionale di Ricerca Metrologica (INRIM), Torino, Italy 4. VTT Technical Research Centre of Finland Ltd, Espoo, Finland 5. Danish Fundamental Metrology (DFM), Hørsholm, Denmark 6. Laboratory for Air Pollution and Environmental Technology, Empa, Dübendorf, Switzerland

The increase of carbon dioxide (CO2) concentration in the atmosphere due to anthropogenic emission is the main cause of global warming. The isotopic composition of atmospheric CO2 provides a powerful tracer for sources and sinks of this potent greenhouse gas applicable at various spatial and temporal scales. The ongoing EMPIR[1] project "Metrology for Stable Isotope Reference Standards (SIRS)"[2] is dedicated to providing metrological support on gaseous CO2 reference materials, and development of spectroscopic methods for isotope ratio measurements of CO2. The uncertainty target is 0.1 permil for δ13C and 0.5 permil for δ18O. Technological advances in mid-IR optical sensors provide paths for high sensitivity isotope ratio determination near 4.5 um, where isotopologues of carbon dioxide have strong ro-vibrational absorption lines and, thus, can be detected at ambient concentrations. Optical isotope ratio spectrometry (OIRS) has substantially increased popularity in atmospheric and biogeochemical research. However, a metrological characterisation of OIRS instruments is required in order to ensure traceability and improved comparability in isotopic signatures, which is of great importance for the scientific community. We present the SIRS protocol for metrological characterisation of the OIRS which also includes recent GAW recommendations [4] and employs the methods reported in the literature [5, and references therein]. Development of the protocol has been done alongside the characterisation of two commercial instruments for CO2 isotope analysis based on DFG source and QCL direct absorption spectroscopy, which have been characterised at PTB and the University of Groningen, respectively. The performance of both instruments demonstrates the precision on the level of 0.01 permil for δ18O and δ13C at atmospheric CO2 concentrations. The ongoing research implies a comparison of the calibration strategies, quantification of matrix gas effects and estimation of the uncertainty budget.

References

[1] https://www.euramet.org/research-innovation/research-empir/

[2] https://www.vtt.fi/sites/SIRS

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[3] B. Kühnreich, S. Wagner, J. C. Habig, O. Möhler, H. Saathoff, V. Ebert, Appl. Phys. B 119:177–187, 2015

[4] GAW report, 242. 19th WMO/IAEA Meeting on Carbon Dioxide, Other Greenhouse Gases and Related Measurement Techniques (GGMT-2017) (27-31 August 2017; Dübendorf, Dübendorf, Switzerland)

[5] David W. T. Griffith, Atmos. Meas. Tech. 11, 6189–6201, 2018 Acknowledgments: The EMPIR initiative is co-funded by the European Union’s Horizon 2020 research and innovation programme and the EMPIR Participating States.

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[3] B. Kühnreich, S. Wagner, J. C. Habig, O. Möhler, H. Saathoff, V. Ebert, Appl. Phys. B 119:177–187, 2015

[4] GAW report, 242. 19th WMO/IAEA Meeting on Carbon Dioxide, Other Greenhouse Gases and Related Measurement Techniques (GGMT-2017) (27-31 August 2017; Dübendorf, Dübendorf, Switzerland)

[5] David W. T. Griffith, Atmos. Meas. Tech. 11, 6189–6201, 2018 Acknowledgments: The EMPIR initiative is co-funded by the European Union’s Horizon 2020 research and innovation programme and the EMPIR Participating States.

P41


Isotope Ratio Stability of CO2 Mixtures in Natural Air

Megumi Isaji1, Jun Sonobe2, Tracey Jacksier2, Matt Matthew3, Takuya Shimosaka4, Shohei Murayama5

1. Air Liquide Laboratories, Tokyo Innovation Campus, Yokosuka-shi, Kanagawa, 239-0847, Japan 2. American Air Liquide, Delaware Innovation Campus 3. Airgas, an Air Liquide company 4. National Metrology Institute Japan, The National Institute of Advanced Industrial Science and Technology 5. Envionmental Management Research Institute, The National Institute of Advanced Industrial Science & Technology

It is essential to utilize internationally traceable reference materials in order to standardize atmospheric CO2 stable isotope measurements. The IAEA international standards for 13C and 18O use calcium carbonate, traceable to Vienna Pee Dee Belemnite (VPDB). A significant discrepancy for both δ13C and δ18O values can often be observed between laboratories because of their specific procedures for generating CO2 from the reference material. Moreover, several reports have described that δ18O values from VPDB have significant variances. Trace amounts of water associated with the phosphoric acid fractionates δ18O during the phosphoric acid dehydration process. In order to minimize this variability, it has been recommended to utilize the new gaseous reference materials, Jena Reference Air Set (JRAS) by Max Planck Institute for Biogeochemistry which is CO2/Air gas mixture. New CO2/Air gas mixtures has been developed as working standard that has not been produced through a calcium carbonate acid-decomposition process. The CO2/Air standard gas mixtures were isotopically adjusted with pure CO2 and Natural air from Izana (Spain). The National Institute of Advanced Industrial Science and Technology (AIST) prepared 400 ppm CO2 gas mixtures with a 2-step blending process into three aluminum cylinders (Luxfer 6061) up to 4 MPa. Prior to filling, two cylinders were evacuated with baking; the third was evacuated without baking. The CO2 δ13C and δ18O values were analyzed by AIST and a 1 year stability test for both δ13C and δ18O was performed. The 1 year stability of δ13C in CO2 was confirmed by AIST and data fluctuations of the three cylinders were within analytical error. Isotope fractionation was not observed at the beginning of the experiment. Furthermore, no fractionation was observed when the pressure of the cylinders was depleted to less than 1.0 MPa. We will also discuss stability of δ18O in CO2.

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Development of international N2O reference materials for site preference measurements

Joanna Rupacher1, Sakae Toyoda2, Heiko Moossen3, Christina Biasi4, Longfei Yu1, Naohiro Yoshida5, Paul Brewer6, Joachim Mohn1

1. Empa, Laboratory for Air Pollution/Environmental Technology, Dübendorf, Switzerland 2. Tokyo Institute of Technology, Department of Chemical Science and Engineering, Yokohama, Japan 3. Max-Planck-Institute for Biogeochemistry (MPI-BGC), Stable Isotope Laboratory (IsoLab), Jena, Germany 4. University of Eastern Finland, Biogeochemistry Research Group, Kuopio, Finland 5. Tokyo Institute of Technology, Earth-Life Science Institute, Tokyo, Japan 6. National Physical Laboratory, Gas and Particle Metrology, Teddington, UK

Nitrous oxide (N2O) is one of the most important greenhouse gases in the Earth’s atmosphere today, as well as a strong stratospheric ozone-depleting gas. The concentration of N2O has been rising since the Industrial Revolution due to changes in many of its sources, both natural and anthropogenic. Measurements of the four most abundant stable isotopologues of N2O (14N14N16O, 15N14N16O, 14N15N16O, and 14N14N18O) can provide a valuable constraint on source attribution of atmospheric N2O. Recent advancements in Optical Isotope Ratio Spectroscopy (OIRS) allow for specific and high precision analysis of 15N substitution in the central (α) and terminal (β) nitrogen position and thus the 15N site preference (SP≡ δ15Nα - δ15Nβ) in N2O. Commercial OIRS analyzers become increasingly available, complementing well-established Isotope Ratio Mass Spectrometry (IRMS), however, to date, no international standards with stated uncertainty exist that link δ15Nα and δ15Nβ to the AIR-N2 isotopic scale. In addition, calibration of OIRS analyzers requires N2O isotope standards in whole air at ambient amount fractions, to account for gas matrix effects and spectral interferences. Within the framework of the EMPIR project “Metrology for Stable Isotope Reference Standards (SIRS),” we aim to develop such standards to be made available to the global community. These will be gaseous standards available as pure N2O or N2O diluted in whole air. To tie the δ15Nα and δ15Nβ values to the AIR-N2 scale, we are synthesizing NH4NO3 salts with a range of δ15N-NO3 and δ15N-NH4 values, each of which will be determined precisely by an international group of laboratories. Each salt will then be thermally decomposed to achieve a quantitative conversion of NH4NO3 to N2O, thus providing several tie-points directly to the internationally accepted AIR-N2 isotope scale. Here, we present the details of this aspect of the EMPIR project and specifically the methods described above.

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Development of international N2O reference materials for site preference measurements

Joanna Rupacher1, Sakae Toyoda2, Heiko Moossen3, Christina Biasi4, Longfei Yu1, Naohiro Yoshida5, Paul Brewer6, Joachim Mohn1

1. Empa, Laboratory for Air Pollution/Environmental Technology, Dübendorf, Switzerland 2. Tokyo Institute of Technology, Department of Chemical Science and Engineering, Yokohama, Japan 3. Max-Planck-Institute for Biogeochemistry (MPI-BGC), Stable Isotope Laboratory (IsoLab), Jena, Germany 4. University of Eastern Finland, Biogeochemistry Research Group, Kuopio, Finland 5. Tokyo Institute of Technology, Earth-Life Science Institute, Tokyo, Japan 6. National Physical Laboratory, Gas and Particle Metrology, Teddington, UK

Nitrous oxide (N2O) is one of the most important greenhouse gases in the Earth’s atmosphere today, as well as a strong stratospheric ozone-depleting gas. The concentration of N2O has been rising since the Industrial Revolution due to changes in many of its sources, both natural and anthropogenic. Measurements of the four most abundant stable isotopologues of N2O (14N14N16O, 15N14N16O, 14N15N16O, and 14N14N18O) can provide a valuable constraint on source attribution of atmospheric N2O. Recent advancements in Optical Isotope Ratio Spectroscopy (OIRS) allow for specific and high precision analysis of 15N substitution in the central (α) and terminal (β) nitrogen position and thus the 15N site preference (SP≡ δ15Nα - δ15Nβ) in N2O. Commercial OIRS analyzers become increasingly available, complementing well-established Isotope Ratio Mass Spectrometry (IRMS), however, to date, no international standards with stated uncertainty exist that link δ15Nα and δ15Nβ to the AIR-N2 isotopic scale. In addition, calibration of OIRS analyzers requires N2O isotope standards in whole air at ambient amount fractions, to account for gas matrix effects and spectral interferences. Within the framework of the EMPIR project “Metrology for Stable Isotope Reference Standards (SIRS),” we aim to develop such standards to be made available to the global community. These will be gaseous standards available as pure N2O or N2O diluted in whole air. To tie the δ15Nα and δ15Nβ values to the AIR-N2 scale, we are synthesizing NH4NO3 salts with a range of δ15N-NO3 and δ15N-NH4 values, each of which will be determined precisely by an international group of laboratories. Each salt will then be thermally decomposed to achieve a quantitative conversion of NH4NO3 to N2O, thus providing several tie-points directly to the internationally accepted AIR-N2 isotope scale. Here, we present the details of this aspect of the EMPIR project and specifically the methods described above.

P43


How good are our measurements of δ13C-CH4?

Sylvia Michel1, Kevin Romiarek1, Bruce Vaughn1, Alyssa Johnson1, Isaac Vimont2, John Miller2, James White1

1. INSTAAR, University of Colorado 2. NOAA ESRL, Global Monitoring Division

The INSTAAR Stable Isotope Lab at the University of Colorado has a twenty-year record of δ13C measurements of methane from a subset of sample flasks in NOAA’s Global Greenhouse Gas Reference Network. These data have been useful for testing hypotheses about the source of the increase in the atmospheric methane burden since 2007 (Schwietzke et al., 2016, Schaeffer et al., 2016, Nisbet et al., 2016). However, the signals interpreted in these studies, with a range of ~0.3 ‰, are small relative to our quoted measurement reproducibility of 0.07 ‰, which is based on surveillance cylinders. As the growth rate of the atmospheric methane burden remains above 5 ppb yr-1, and more scrutiny is given to both natural and anthropogenic emission sources, it will become increasingly more important not to over- or understate uncertainties in critical δ13C-CH4 measurements. Here we ask what we can do to improve our data quality, both by increasing measurement precision from our analytical system, and by strengthening our post-processing quality control. Analytical uncertainty dominates the error in our calculations of global means– unlike for methane mole fraction, where uncertainty is dominated by variability in the atmosphere or by the choice of sites in the network – and we test different metrics for applying error to our calculations of global means. We also test the effect of our network on the globally averaged time series. Despite the large noise-to-signal ratio, our measurements are useful for understanding changes in the global methane budget.

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Calibration Methodology for the Scripps 13C/12C and 18O/16O stable isotope program 1992-2018

Keeling Ralph1, Lueker Timothy1, Bollenbacher Alane1, Walker Stephen1, Morgan Eric1


We describe the calibration method for measurements of 13C/12C and 18O/16O ratios of atmospheric CO2 by the Scripps CO2 program from 1992-2018. The method depends principally on repeat analysis of CO2 derived from a suite of high-pressure gas cylinders filled with compressed natural air pumped at La Jolla. The first set of three cylinders were given isotopic assignments in 1994 based on comparisons with material artifacts NBS16, NBS17, and NBS19. Six cylinders subsequently brought into service were assigned values by comparing directly or indirectly with this first set. A tenth cylinder with natural CO2 in air was obtained from MPI Jena. All cylinders contain natural levels of N2O. Aliquots of CO2 from these cylinders have repeatedly been extracted into heat-sealed glass ampoules before introduction into the mass spectrometer. Some of these ampoules have been stored for many years before analysis, allowing long-term isotopic drift of the cylinders to be quantified. We find that five of the nine La Jolla cylinders have drifted downwards in δ18O, δ13C, or both, at rates up to of -0.11‰ per decade. The Jena cylinder has drifted upwards in δ18O at a rate of +0.10 ‰ per decade. The calibration method includes corrections for cylinder drift, isobaric interferences, and the presence of N2O. Drift-corrected analyses of the Jena cylinder establishes offsets of +0.037 ‰ in δ13C and +0.041 ‰ in δ18O between the Scripps and JRAS isotopic scales (Scripps more positive).

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Calibration Methodology for the Scripps 13C/12C and 18O/16O stable isotope program 1992-2018

Keeling Ralph1, Lueker Timothy1, Bollenbacher Alane1, Walker Stephen1, Morgan Eric1


We describe the calibration method for measurements of 13C/12C and 18O/16O ratios of atmospheric CO2 by the Scripps CO2 program from 1992-2018. The method depends principally on repeat analysis of CO2 derived from a suite of high-pressure gas cylinders filled with compressed natural air pumped at La Jolla. The first set of three cylinders were given isotopic assignments in 1994 based on comparisons with material artifacts NBS16, NBS17, and NBS19. Six cylinders subsequently brought into service were assigned values by comparing directly or indirectly with this first set. A tenth cylinder with natural CO2 in air was obtained from MPI Jena. All cylinders contain natural levels of N2O. Aliquots of CO2 from these cylinders have repeatedly been extracted into heat-sealed glass ampoules before introduction into the mass spectrometer. Some of these ampoules have been stored for many years before analysis, allowing long-term isotopic drift of the cylinders to be quantified. We find that five of the nine La Jolla cylinders have drifted downwards in δ18O, δ13C, or both, at rates up to of -0.11‰ per decade. The Jena cylinder has drifted upwards in δ18O at a rate of +0.10 ‰ per decade. The calibration method includes corrections for cylinder drift, isobaric interferences, and the presence of N2O. Drift-corrected analyses of the Jena cylinder establishes offsets of +0.037 ‰ in δ13C and +0.041 ‰ in δ18O between the Scripps and JRAS isotopic scales (Scripps more positive).

P45


NIWA’s δ13C-CO2 measurement programme: Twenty years of monitoring in New Zealand and Antarctica.

Rowena Moss1, Gordon Brailsford1, Mike Kotkamp1, Ross Martin1, Sylvia Nichol1, Dan Smale1, Peter Sperlich1, Sara Mikaloff-Fletcher1, Pieter Tans2, Sylvia Englund Michel3, Ralph Keeling4, David Griffith5 1National Institute of Water and Atmospheric Research (NIWA), Wellington, New Zealand 2 National Oceanic and Atmospheric Administration (NOAA), Boulder, Colorado, USA 3Institute of Arctic and Alpine Research (NSTAAR), Boulder, Colorado, USA 4Scripps Institution of Oceanography, San Diego, California, USA 5University of Wollongong, New South Wales, Australia.

NIWA is monitoring atmospheric trace gas species at multiple locations in New Zealand and Antarctica. NIWA’s main monitoring sites include i) Baring Head (BHD), a coastal site at the Southern tip of New Zealand’s North Island, ii) Lauder (LAU), an inland site in the central South Island of New Zealand and iii) Arrival Heights (ARH), an observatory on Ross Island in McMurdo Sound in Antarctica. Stable carbon isotopes in atmospheric carbon dioxide (13C-CO2) are measured at all three sites and represent a tracer to constrain CO2 fluxes. NIWA’s 13C-CO2 measurements started in 1997 at BHD and ARH, while it commenced in 2009 at LAU. An in situ FTIR instrument has also been measuring 13C-CO2 for the last 5 years at LAU providing a continuous timeseries for this site. At all three sites, air is sampled in flasks during specific meteorological conditions, i.e. during Southerly events at BHD to sample Southern Ocean background air, or during mid-afternoon at LAU when the atmospheric boundary layer is well mixed. All flasks are analysed for 13C-CO2 at the main gaslab in Wellington, using the same Gas Chromatography coupled Isotope Ratio Mass Spectrometry (GC-IRMS) system, ensuring optimal internal data consistency. Our instrument comprises a purpose-built GC unit and a commercial IRMS (MAT 252, Thermo Fisher, Bremen, Germany). In the last 20 years, the 13C-CO2 monitoring programme has generated 1,708 measurements, with about 1182 from BHD, 158 from ARH, 230 from LAU. BHD is also sampled for 13C-CO2 analysis within the NOAA and the Scripps flask networks, providing intercomparison time series.

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Multipoint normalization of δ18O of water against the VSMOW2-SLAP2 scale with an uncertainty assessment

Taewan Kim1, Sangbum Hong2, Jeongsoon Lee1, Jeong Sik Lim1

1. Korea Research Institute of Standards and Science 2. Korea Polar Research Institute

In this study, we measured the oxygen stable isotope ratio of drinking water using gas chromatography isotope ratio mass spectrome-try. The δ18O value of drinking water was normalized based on the Vienna Standard Mean Ocean Water 2 (VSMOW2), Standard Light Antarctic Precipitation 2 (SLAP2), and Greenland Ice Sheet Precipitation (GISP) scale by CO2 equilibrium for 24 h. The isotope ratio responses of a dummy sample drifted as much as 0.145‰ due to a significant decrease in the amount of injected sample. The autodilution technique improved measurement precision of the δ18O of dummy sample two-fold compared to that without autodilution to 0.025‰. The autodilution of an injected concentration of equilibrated CO2 also helped improve the measurement precision of the isotope ratio response. The drift of the ratio responses was tested using linear model regression to validate linearity within the sample concentration and isotope ratio ranges. Measurement reliability was assessed using various statistical approaches. One-way analysis of variance verified non-reproducible results of individual measurements. Normalization uncertainties were then assessed by various normalization schemes including two-point and three-point values consisting of the VSMOW2, SLAP2, and GISP standards, showing equivalent results associated with similar extent of normalization uncertainties among various normalization methods. In particular, the uncertainty of the GISP (0.09‰) contributed to one-third of the total normalization uncertainty, implying that the three-point normalization can be improved by a potential standard of which uncertainty is equivalent to the bracketing standards, VSMOW2 (0.02‰) and SLAP2 (0.02‰).

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Multipoint normalization of δ18O of water against the VSMOW2-SLAP2 scale with an uncertainty assessment

Taewan Kim1, Sangbum Hong2, Jeongsoon Lee1, Jeong Sik Lim1

1. Korea Research Institute of Standards and Science 2. Korea Polar Research Institute

In this study, we measured the oxygen stable isotope ratio of drinking water using gas chromatography isotope ratio mass spectrome-try. The δ18O value of drinking water was normalized based on the Vienna Standard Mean Ocean Water 2 (VSMOW2), Standard Light Antarctic Precipitation 2 (SLAP2), and Greenland Ice Sheet Precipitation (GISP) scale by CO2 equilibrium for 24 h. The isotope ratio responses of a dummy sample drifted as much as 0.145‰ due to a significant decrease in the amount of injected sample. The autodilution technique improved measurement precision of the δ18O of dummy sample two-fold compared to that without autodilution to 0.025‰. The autodilution of an injected concentration of equilibrated CO2 also helped improve the measurement precision of the isotope ratio response. The drift of the ratio responses was tested using linear model regression to validate linearity within the sample concentration and isotope ratio ranges. Measurement reliability was assessed using various statistical approaches. One-way analysis of variance verified non-reproducible results of individual measurements. Normalization uncertainties were then assessed by various normalization schemes including two-point and three-point values consisting of the VSMOW2, SLAP2, and GISP standards, showing equivalent results associated with similar extent of normalization uncertainties among various normalization methods. In particular, the uncertainty of the GISP (0.09‰) contributed to one-third of the total normalization uncertainty, implying that the three-point normalization can be improved by a potential standard of which uncertainty is equivalent to the bracketing standards, VSMOW2 (0.02‰) and SLAP2 (0.02‰).

P47


Developing a system to measure nitrous oxide isotopomers in air

Peter Sperlich1, Mike Harvey1, Ross Martin1, John McGregor1, Colin Nankivell1

1. NIWA

Nitrous oxide (N2O) is a powerful greenhouse gas as well as an ozone-depleting substance. While the global N2O budget is fairly well constrained, our knowledge of the processes of N2O formation is limited. The analysis of N2O isotopomers may be the key to provide such information: The site preference (14N15N16O(α) – 15N14N16O(β)) is thought to be independent of the substrate isotopic composition, and furthermore depends only on the reaction(s) forming and destroying N2O. As a new potential tool, site preferences may enable the differentiation between nitrification and denitrification production pathways including the distinct impact of several microbial communities. Quantum cascade laser spectrometers – such as our Los Gatos Research N2O1A-23e-EP analyser (LGR) – make rapid measurement of isotopomer variants. However, high N2O mixing ratios are required in order to detect small variations of the site preference in air samples. Therefore, we developed a N2O pre-concentration system that is coupled to our LGR, which we modified to analyse discrete samples. We show experiments that demonstrate the performance of the cryogenic N2O pre-concentrating unit and the modified LGR.

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P48


Optical method for clumped isotope measurements - the case of carbon dioxide

Ivan Prokhorov1, Tobias Kluge1, Christof Janssen2

1. Institute of Environmental Physics, Heidelberg University, Heidelberg, Germany 2. LERMA-IPSL, Sorbonne Universite, CNRS, Observatoire de Paris, PSL Universite, Paris, France

The isotope exchange between the doubly substituted 13C16O18O molecule and the carbon dioxide isotopologue 12C16O16O has become an exciting new tool for geochemical and atmospheric research. Applications of this isotope proxy and thermometer range from stratospheric chemistry to carbonate-based geothermometry studies. Full exploitation of this new tool is nevertheless limited due to time-consuming and costly analysis using mass spectrometric instrumentation. Laser spectroscopic measurement methods, on the contrary, might overcome many of these limitations, in particular, the serious constraint of isobaric interferences. We present a laser-based CO2 isotopologue thermometer with capability for rapid analysis and simplified sample preparation. An important advantage of the new instrument is that it can unambiguously measure all isotopologues of the 12C16O16O + 13C16O18O ↔ 13C16O16O + 12C16O18O exchange reaction. Its equilibrium constant and the corresponding temperature are therefore determined directly. The current measurement precision is better than 50 ppm within about 60 to 90 minutes [1]. Unlike mass spectrometric measurements, the laser approach is also independent of the isotope composition of the calibration gas. The use of an uncalibrated working reference is therefore sufficient, and usage of international calibration standards is obsolete. This and the relatively low cost and size factors should help to spread this frontier science methodology to more laboratories and technological applications. Other isotopologues of carbon dioxide, such as 12C18O18O, and further molecules can be accessed using the methodology. This opens up exciting new avenues in isotope research.

Reference

[1] Prokhorov, Kluge, Janssen, "Optical clumped isotope thermometry of carbon dioxide", Scientific Reports 9, 4765 (2019)

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Optical method for clumped isotope measurements - the case of carbon dioxide

Ivan Prokhorov1, Tobias Kluge1, Christof Janssen2

1. Institute of Environmental Physics, Heidelberg University, Heidelberg, Germany 2. LERMA-IPSL, Sorbonne Universite, CNRS, Observatoire de Paris, PSL Universite, Paris, France

The isotope exchange between the doubly substituted 13C16O18O molecule and the carbon dioxide isotopologue 12C16O16O has become an exciting new tool for geochemical and atmospheric research. Applications of this isotope proxy and thermometer range from stratospheric chemistry to carbonate-based geothermometry studies. Full exploitation of this new tool is nevertheless limited due to time-consuming and costly analysis using mass spectrometric instrumentation. Laser spectroscopic measurement methods, on the contrary, might overcome many of these limitations, in particular, the serious constraint of isobaric interferences. We present a laser-based CO2 isotopologue thermometer with capability for rapid analysis and simplified sample preparation. An important advantage of the new instrument is that it can unambiguously measure all isotopologues of the 12C16O16O + 13C16O18O ↔ 13C16O16O + 12C16O18O exchange reaction. Its equilibrium constant and the corresponding temperature are therefore determined directly. The current measurement precision is better than 50 ppm within about 60 to 90 minutes [1]. Unlike mass spectrometric measurements, the laser approach is also independent of the isotope composition of the calibration gas. The use of an uncalibrated working reference is therefore sufficient, and usage of international calibration standards is obsolete. This and the relatively low cost and size factors should help to spread this frontier science methodology to more laboratories and technological applications. Other isotopologues of carbon dioxide, such as 12C18O18O, and further molecules can be accessed using the methodology. This opens up exciting new avenues in isotope research.

Reference

[1] Prokhorov, Kluge, Janssen, "Optical clumped isotope thermometry of carbon dioxide", Scientific Reports 9, 4765 (2019)

P49


A cryogen-free automated measurement system of stable carbon isotope ratio of atmospheric methane

Taku Umezawa1, Stephen Andrews2, Takuya Saito1

1. National Institute for Environmental Studies, Tsukuba, Japan 2. University of York, York, UK

Although methane plays an important role in climate change and atmospheric chemistry, its global budget remains quantitatively uncertain due mainly to a wide variety of source types. The stable carbon isotope ratio of atmospheric methane (δ13C-CH4) is useful for separating contributions of different source categories, but due to the complex and laborious analysis, limited measurement data exists. We present a new system for δ13C-CH4 measurement, optimized for the automated analysis of air samples. Although the system is designed in principle similarly to those in previous studies, we successfully set up the system with no use of cryogens (e.g. liquid nitrogen) and attained reproducibility sufficient for atmospheric measurement (~0.1‰). We performed automated continuous measurements of ambient air outside our laboratory at about hourly intervals for 2 months, which characterized imprint of local methane sources well. Future measurement operation for flask air samples from existing atmospheric monitoring programs will provide large number of atmospheric δ13C-CH4 data.

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Measuring stables isotopes of CO2 (13C and 17,18O) in vertical profiles over the Amazon Raiane A.L.Neves1, Luciana V.Gatti1,2, Luana S.Basso1, Luciano Marani1, Stephene P.Crispim1, Caio S.C.Correia1,2, Lucas G.Domingues1,2, Dipayan Paul3, Bert Scheeren3, Getachew A.Adnew4, Thomas Röckmann4, Wouter Peters5,6 1. National Institute for Space Research (INPE/CCST/LaGEE), São José dos Campos, SP, Brazil 2. Nuclear and Energy Research Institute (IPEN), SP, Brazil 3. Centre for Isotope Res. Energy and Sust. Res.Institute Groningen, Groningen University, The Netherlands 4. Institute for Marine and Atmospheric Research, Utrecht University, The Netherlands 5. Dep. of Meteorology and Air Quality Environ. Sciences Group, Wageningen University, The Netherlands 6. Centre for Isotope Res. Energy and Sust. Res.Institute Groningen, Groningen University, The Netherlands

The most abundant Greenhouse gas (GHG) in our atmosphere is carbon dioxide (CO2) and in 2017 its concentration reached 146% of pre-industrial levels [1]. In the period 2007-2016 around 44% of total CO2 emissions from human activities accumulated in the atmosphere, while 22% was stored in the ocean and 28% on land [1], but important questions remain on the processes behind this partitioning, and their persistence under climate change. The study of the stable isotopologues of CO2 – 13COO, C17OOand C18OO – can provide new insights, for example on the efficiency of water use during photosynthesis [2].They also can be helpful in determining the temporal and spatial distribution of sources and sinks, and to estimate the contributions of C3 and C4 to total primary productivity [3].In 2010 we extended our program of GHG measurements (CO2, CH4, N2O, SF6) by making vertical profiles in 3 more sites over the Amazon [4]. Measurements are made by weekly at four sites: The first SAN (2.86ºS; 54.95ºW), and the tree news: RBA (9.01ºS, 64.72ºW), ALF 98.80ºS, 56.75ºW) and TEF (3.31ºS, 65.8°W), which started in 2013 to replace TAB (5.96ºS, 70.06ºW). Since June 2016, 700 ml of air from each flask has been used to extract pure CO2 in glass vials, to determine δ13C ratios in CO2 at the stable isotope laboratory in Groningen, the Netherlands. We currently have close to 1500 vials ready for analysis. In addition, directanalysis on air in each flask started in Feb-2017 at LaGEE. CO2 and its stable isotopes (δ13C, and Excess-17O, derived from δ17O and δ18O) are measured on a TILDAS-D CO2 Analyzer from Aerodyne Inc, through a limited number (12-16) repeat measurements of 15ml aliquots of air, interspersed with a measurement of a known reference gas for normalization. Note that a useful measurement of the oxygen isotopes necessitated rigorous drying (< 2 deg dewpoint T) of very humid tropical air (2-4% H2O), using a custom built Nafion drying system (Paul et al., 2019, in preparation). Total sample usage from the isotope system is ~275ml including flushing of lines and manifolds. We will present the stable isotope program at LaGEE and the results we have accumulated so far at the four sites, as well as details on the precision, repeatability, stability, and calibration of the measurements.

References

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Measuring stables isotopes of CO2 (13C and 17,18O) in vertical profiles over the Amazon Raiane A.L.Neves1, Luciana V.Gatti1,2, Luana S.Basso1, Luciano Marani1, Stephene P.Crispim1, Caio S.C.Correia1,2, Lucas G.Domingues1,2, Dipayan Paul3, Bert Scheeren3, Getachew A.Adnew4, Thomas Röckmann4, Wouter Peters5,6 1. National Institute for Space Research (INPE/CCST/LaGEE), São José dos Campos, SP, Brazil 2. Nuclear and Energy Research Institute (IPEN), SP, Brazil 3. Centre for Isotope Res. Energy and Sust. Res.Institute Groningen, Groningen University, The Netherlands 4. Institute for Marine and Atmospheric Research, Utrecht University, The Netherlands 5. Dep. of Meteorology and Air Quality Environ. Sciences Group, Wageningen University, The Netherlands 6. Centre for Isotope Res. Energy and Sust. Res.Institute Groningen, Groningen University, The Netherlands

The most abundant Greenhouse gas (GHG) in our atmosphere is carbon dioxide (CO2) and in 2017 its concentration reached 146% of pre-industrial levels [1]. In the period 2007-2016 around 44% of total CO2 emissions from human activities accumulated in the atmosphere, while 22% was stored in the ocean and 28% on land [1], but important questions remain on the processes behind this partitioning, and their persistence under climate change. The study of the stable isotopologues of CO2 – 13COO, C17OOand C18OO – can provide new insights, for example on the efficiency of water use during photosynthesis [2].They also can be helpful in determining the temporal and spatial distribution of sources and sinks, and to estimate the contributions of C3 and C4 to total primary productivity [3].In 2010 we extended our program of GHG measurements (CO2, CH4, N2O, SF6) by making vertical profiles in 3 more sites over the Amazon [4]. Measurements are made by weekly at four sites: The first SAN (2.86ºS; 54.95ºW), and the tree news: RBA (9.01ºS, 64.72ºW), ALF 98.80ºS, 56.75ºW) and TEF (3.31ºS, 65.8°W), which started in 2013 to replace TAB (5.96ºS, 70.06ºW). Since June 2016, 700 ml of air from each flask has been used to extract pure CO2 in glass vials, to determine δ13C ratios in CO2 at the stable isotope laboratory in Groningen, the Netherlands. We currently have close to 1500 vials ready for analysis. In addition, directanalysis on air in each flask started in Feb-2017 at LaGEE. CO2 and its stable isotopes (δ13C, and Excess-17O, derived from δ17O and δ18O) are measured on a TILDAS-D CO2 Analyzer from Aerodyne Inc, through a limited number (12-16) repeat measurements of 15ml aliquots of air, interspersed with a measurement of a known reference gas for normalization. Note that a useful measurement of the oxygen isotopes necessitated rigorous drying (< 2 deg dewpoint T) of very humid tropical air (2-4% H2O), using a custom built Nafion drying system (Paul et al., 2019, in preparation). Total sample usage from the isotope system is ~275ml including flushing of lines and manifolds. We will present the stable isotope program at LaGEE and the results we have accumulated so far at the four sites, as well as details on the precision, repeatability, stability, and calibration of the measurements.

References

P50


[1] WMO-World Meteorological Organization. Greenhouse Gas Bulletin –2017.

[2] Peters et al., “Increased Water-Use Efficiency and Reduced CO2 Uptake by Plants During Droughts at a Continental Scale.” Nature Geoscience, 2018.

[3] Suits, N.S., Denning, A.S., et al. Simulations of carbon isotope discrimination of the terrestrial biosphere. Global Biogeochemical Cycles, v.19, p. 1-15, 2005.

[4] Gatti, L.V., Gloor, M., et. al. Drought sensitivity of Amazonian carbon balance revealed by atmospheric measurements. Nature, v.506, p.76-79, 2014.

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On the performance of simultaneous measurements of δ13C-CO2, δ18O-CO2 and δ17O-CO2 by Quantum Cascade Dual-Laser Absorption Spectrometry in whole air atmospheric samples from Lutjewad station, the Netherlands Bert A. Scheeren1, Farilde M. Steur1, David D. Nelson2, Getachew A. Adnew3, Wouter Peters4,1, Harro A.J. Meijer1 1. Center for Isotope Research (CIO), University of Groningen, Groningen, The Netherlands 2. Aerodyne Research, Inc., Billerica, MA, USA 3. Institute for Marine and Atmospheric Research (IMAU), Utrecht University, The Netherlands 4. Department of Meteorology and Air Quality, Wageningen University

We present the first results of δ13C-CO2, δ18O-CO2, δ17O-CO2 and “excess” 17O-CO2 or Δ17O-CO2 measurements in air samples using new Aerodyne Quantum Cascade Dual-Laser Spectrometer system (QCDLAS). The air samples are collected at Lutjewad monitoring station in the Netherlands, located at the Dutch Wadden sea coast (6.353° E, 53.404° N) in a rural environment. The Δ17O-CO2 anomaly is defined as the deviation from normal mass dependent fractionation reflected in the meteoric water line (following a slope of 0.528), resulting from isotopic exchange between water and CO2 occurring over water bodies and in leaf stomata. As such, atmospheric Δ17O-CO2 has been used as a parameter to study gross primary production (GPP), notably as function of water availability. Here, the determination of Δ17O-CO2 is derived from the direct measurement of δ17O-CO2 next to δ18O-CO2 (Δ17O = ln(δ17O +1)-0.528×ln(δ18O +1)). We give an overview of the instrument set-up, performance, as well as problems we encountered during its 2 years of operation. Furthermore, we show results from flask samples collected at 60 m altitude on a bi-weekly rate at Lutjewad station spanning from July 2016 until January 2019. The location of Lutjewad station allows to measure clean marine background air from the north-northwest (~15% of the time) in contrast to more polluted continental air from a prevalent south-westerly direction (~50% of the time). Our observations include the summer of 2018 which saw exceptional hot and dry conditions in large parts of Europe, including the Netherlands, leading to droughts, heatwaves and wildfires. Hence, using the summer 2018 results we discuss the potential of using the Δ17O-CO2 signal as a tracer for suppressed plant assimilation due to water stress.

143

P51


On the performance of simultaneous measurements of δ13C-CO2, δ18O-CO2 and δ17O-CO2 by Quantum Cascade Dual-Laser Absorption Spectrometry in whole air atmospheric samples from Lutjewad station, the Netherlands Bert A. Scheeren1, Farilde M. Steur1, David D. Nelson2, Getachew A. Adnew3, Wouter Peters4,1, Harro A.J. Meijer1 1. Center for Isotope Research (CIO), University of Groningen, Groningen, The Netherlands 2. Aerodyne Research, Inc., Billerica, MA, USA 3. Institute for Marine and Atmospheric Research (IMAU), Utrecht University, The Netherlands 4. Department of Meteorology and Air Quality, Wageningen University

We present the first results of δ13C-CO2, δ18O-CO2, δ17O-CO2 and “excess” 17O-CO2 or Δ17O-CO2 measurements in air samples using new Aerodyne Quantum Cascade Dual-Laser Spectrometer system (QCDLAS). The air samples are collected at Lutjewad monitoring station in the Netherlands, located at the Dutch Wadden sea coast (6.353° E, 53.404° N) in a rural environment. The Δ17O-CO2 anomaly is defined as the deviation from normal mass dependent fractionation reflected in the meteoric water line (following a slope of 0.528), resulting from isotopic exchange between water and CO2 occurring over water bodies and in leaf stomata. As such, atmospheric Δ17O-CO2 has been used as a parameter to study gross primary production (GPP), notably as function of water availability. Here, the determination of Δ17O-CO2 is derived from the direct measurement of δ17O-CO2 next to δ18O-CO2 (Δ17O = ln(δ17O +1)-0.528×ln(δ18O +1)). We give an overview of the instrument set-up, performance, as well as problems we encountered during its 2 years of operation. Furthermore, we show results from flask samples collected at 60 m altitude on a bi-weekly rate at Lutjewad station spanning from July 2016 until January 2019. The location of Lutjewad station allows to measure clean marine background air from the north-northwest (~15% of the time) in contrast to more polluted continental air from a prevalent south-westerly direction (~50% of the time). Our observations include the summer of 2018 which saw exceptional hot and dry conditions in large parts of Europe, including the Netherlands, leading to droughts, heatwaves and wildfires. Hence, using the summer 2018 results we discuss the potential of using the Δ17O-CO2 signal as a tracer for suppressed plant assimilation due to water stress.

P52


Pha Din GAW regional station and development orientation of climate change observing network in VietNam

Thi Quynh Hoa Vu1, Thi Van Anh Tong1

1. Viet Nam Hydrological and Meteorological Administration

Greenhouse gases (GHG) and aerosols in the atmosphere are very closely linked to global warming and climate change, where it is carefully monitored to ensure that GHG emissions are always low. In view of the global GHG concentrations they showed an increase in pattern, and one of them is because of human activities. However, in large regions of Africa, South-East Asia and South America, observations of atmospheric variables are not available. The project Capacity Building and Twinning for Climate Observing Systems (CATCOS) establishes measurement of these essential climate variables at selected stations in four countries (including VietNam). In close collaboration, Swiss and international partner instituations make the measured data traceable, quality-controlled and available at the International Data Centers for aerosols or GHG, respectively. Within the CATCOS Project, the National Hydro-Meteorological Service of Vietnam (NHMS) together with the Paul Scherrer Institute (PSI) and the Swiss Federal Laboratories for Materials Science and Technology (Empa) established aerosol and greenhouse gas observations at Pha Din station. Subsequent to the successful implementation of the measuring equipment, joint efforts concentrate on training and twinning activities. Pha Din station has been offcially operated from March 2014. In this poster, I will present: i) The introduction of Pha Din GAW regional station, ii) The locations, iii) The installation, iv) The equipment/Data, v) The training/Workshop, vi) The development orientation, vii) Data series of Greenhouse gases from 2014 to 2018.

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Where is the missing CO2? A regional multi-species approach to trace the fate of atmospheric CO2 in Fiordland National Park, New Zealand.

Peter Sperlich1, Sara Mikaloff Fletcher1, Gordon Brailsford1, Rowena Moss1, Jocelyn Turnbull2, Liz Keller2, Steve Montzka3, Mao-Chang Liang4

1. National Institute of Water and Atmospheric Research (NIWA), Wellington, New Zealand 2. GNS-Science, Lower Hutt, New Zealand 3. National Ocean Atmosphere Administration (NOAA), Boulder, United States of America 4. Institute of Earth Sciences, Academia Sinica, Taiwan

A robust understanding of CO2 fluxes is vital for accurate estimates of future atmospheric carbon dioxide (CO2) levels. However, current estimation techniques show large disagreement on terrestrial CO2 fluxes. In particular, atmospheric data suggests a larger net CO2 sink than previously thought for New Zealand’s Fiordland region, one of our largest indigenous, temperate rainforests with an area of 12,600 km2 and a mean annual precipitation of up to 15 m. We will test the hypothesis that Fiordland’s forest is more productive than previously thought with flask samples in air parcels before and after the air has passed over Fiordland’s forests. We will use a multi-tracer ensemble to determine biogeochemical trace-gas exchange on spatial scales of 50-100 km. While measurements of CO2 mole fractions indicate CO2 level changes directly, measurements of δ13C-CO2 distinguish the forest’s net CO2 uptake due to the characteristic isotope fractionation during photosynthesis. A modified Keeling-Plot-Analysis of existing CO2 mixing and isotope ratio data from a coastal site (Baring Head) and inland site (Lauder) suggests this approach is suitable to resolve atmospheric gradients on ~100 km scales. Moreover, we will use COS (carbonyl sulfide) as an independent tracer for photosynthetic CO2 uptake, and Δ14C-CO2 to examine ecosystem respiration and residence times. We will also analyse δ18O, Δ17O and clumped isotopes in CO2 and assess the suitability of these tracers to further constrain Fiordland’s CO2 fluxes. Our measurement results will be interpreted using state-of-the-art bottom-up and top-down models. This study will help to better understand regional CO2 fluxes on process levels and assess the most suitable tracers for regional carbon cycle observations in comparable ecosystems.

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Where is the missing CO2? A regional multi-species approach to trace the fate of atmospheric CO2 in Fiordland National Park, New Zealand.

Peter Sperlich1, Sara Mikaloff Fletcher1, Gordon Brailsford1, Rowena Moss1, Jocelyn Turnbull2, Liz Keller2, Steve Montzka3, Mao-Chang Liang4

1. National Institute of Water and Atmospheric Research (NIWA), Wellington, New Zealand 2. GNS-Science, Lower Hutt, New Zealand 3. National Ocean Atmosphere Administration (NOAA), Boulder, United States of America 4. Institute of Earth Sciences, Academia Sinica, Taiwan

A robust understanding of CO2 fluxes is vital for accurate estimates of future atmospheric carbon dioxide (CO2) levels. However, current estimation techniques show large disagreement on terrestrial CO2 fluxes. In particular, atmospheric data suggests a larger net CO2 sink than previously thought for New Zealand’s Fiordland region, one of our largest indigenous, temperate rainforests with an area of 12,600 km2 and a mean annual precipitation of up to 15 m. We will test the hypothesis that Fiordland’s forest is more productive than previously thought with flask samples in air parcels before and after the air has passed over Fiordland’s forests. We will use a multi-tracer ensemble to determine biogeochemical trace-gas exchange on spatial scales of 50-100 km. While measurements of CO2 mole fractions indicate CO2 level changes directly, measurements of δ13C-CO2 distinguish the forest’s net CO2 uptake due to the characteristic isotope fractionation during photosynthesis. A modified Keeling-Plot-Analysis of existing CO2 mixing and isotope ratio data from a coastal site (Baring Head) and inland site (Lauder) suggests this approach is suitable to resolve atmospheric gradients on ~100 km scales. Moreover, we will use COS (carbonyl sulfide) as an independent tracer for photosynthetic CO2 uptake, and Δ14C-CO2 to examine ecosystem respiration and residence times. We will also analyse δ18O, Δ17O and clumped isotopes in CO2 and assess the suitability of these tracers to further constrain Fiordland’s CO2 fluxes. Our measurement results will be interpreted using state-of-the-art bottom-up and top-down models. This study will help to better understand regional CO2 fluxes on process levels and assess the most suitable tracers for regional carbon cycle observations in comparable ecosystems.

P54


Atmospheric trace gas observations: Latest update from the Cape Point station

Casper Labuschagne1, Thumeka Mkololo1, Warren Joubert1, Lynwill Martin1, Ernest Mbambalala1, Danie vd Spuy1

1. South African Weather Service, Cape Point Global Atmosphere Watch

The Cape Point (CPT) long-term trace gas station, which celebrated its 40th year of existence in 2018, has become a valuable source of climatic information for modelers and policy makers alike. The station’s carbon dioxide (CO2) record for which measurements started in 1993, is still showing an unabated upward trend, displaying an annual growth rate that currently ranges between 2.0 – 2.4 ppm/yr for the 2018 -19 season. On a decadal scale, the background mean values have increased by 11.78, 13.14, and 21.10 ppm respectively for each of the past 3 decades. Similarly, the atmospheric methane (CH4) growth at CPT has recently displayed a much stronger increase - roughly doubling from levels of 5.5 ppb/yr in the early 2000’s to well over 11.0 ppb/yr during the most recent 3 years. The observed increase from the CPT record follows a similar global trend, which are currently believed to be the result of a combination of multiple factors, such as changes in wetland dynamics (microbial activity), decreased biomass burning and OH chemistry. The CPT nitrous oxide (N2O) measurements have been resumed again in late 2017 with the addition of a high frequency device, also capable of isotopic measurements. The long-term average (0.88 ppb/yr obtained from a linear fit) at CPT closely resemble that of the global annual mean of 0.93 ppb/yr. Contrasting the observed increases in greenhouse gas atmospheric mixing ratios, our carbon monoxide (CO) record on the other hand, has displayed a small, but significant decreasing trend over the past 8+ years having started around 2005. This downward trend ranging between -0.7 and -1.6 ppb/yr has also been observed in the UTLS via remote sensing and seems to be most prevalent in the southern hemisphere mid latitude region. The exact driving forces for this are still under investigation. Cape Point’s 33year old surface ozone record is also displaying some interesting long-term features of late. The bulk of the historic data record had a smoothed 12month growth rate that varies between -0.5 – 0.5 ppb/yr, however since 2015 this feature has changed with observed growth rates of 1 – 3.5 ppb/yr observed for 2016 – 2018 period. The processes responsible for these observed changes are still being investigated and early indications points to possible stratospheric tropospheric exchange enhancements within the southern hemisphere mid latitude region (typically within the Hadley cell circulation domain).

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High frequency measurements of atmospheric HFCs at a regional monitoring site in East Asia and the implications for regional emissions

Sunyoung Park1, Hyeri Park2, Mi-Kyung Park2, Shalan Li2, Jooil Kim3, Alison Redington4, Alistair Manning4

1. Department of Oceanography, Kyungpook National University, Republic of Korea 2. Kyungpook Institute of Oceanography, Kyungpook National University, Republic of Korea 3. Scripps Institution of Oceanography, UCSD, USA 4. Hadley Centre, UK Met Office, UK

Chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs) are all long-lived potent greenhouse gases affecting climate for decades to millennia after being emitted. The radiative forcing reduced by controlling ozone depleting CFCs and HCFCs under the Montreal Protocol (MP) was estimated to be as much as 35% of that of CO2 in 2010 [1]. However, this climate benefit achieved by the MP was considered to be significantly offset by increased use of HFCs with 100-year GWPs ranging from 100 to 14000 as substitutes for CFCs and HCFCs and thus significant future increases in HFC-associated warming. Finally the Kigali Amendment to the MP, which comes into force in 2019, sets schedules for the phasedown of global production and consumption of HFCs. This study presents 9-year, high frequency atmospheric measurement records of major HFCs (HFC-23, HFC-134a, HFC-32, HFC-125, HFC-152a and HFC-143a) obtained at a regional monitoring site in East Asia (Gosan station, Jeju Island, Korea; 33°N, 126°E) from 2008 to 2017. We examine the magnitude and changes of observed pollution events for each HFC compound, and suggest their annual emissions originating from eastern China, the Korean peninsula and western Japan for the period 2008–2017. The emission estimates are made by interspecies correlation method using atmospheric observations of other species measured at Gosan, and by inverse techniques based on NAME–InTEM (Numerical Atmospheric dispersion Modeling Environment–Bayesian Inversion Technique for Emissions Modelling) and on FlexInvert (a Bayesian inversion framework based on the FLEXPART Lagrangian transport model). These ‘top-down’ estimates are compared with country-specific, inventory-based ‘bottom-up’ emission estimates. We also discuss the contributions of country-based, six HFCs’ CO2-eq emissions to the global total and non-Annex I countries’ CO2-eq emissions.

Reference

[1] Velders et al. (2012), Preserving Montreal Protocol climate benefits by limiting HFCs, Science, 24, 335(6071), 922-3, doi: 10.1126/science.1216414.

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High frequency measurements of atmospheric HFCs at a regional monitoring site in East Asia and the implications for regional emissions

Sunyoung Park1, Hyeri Park2, Mi-Kyung Park2, Shalan Li2, Jooil Kim3, Alison Redington4, Alistair Manning4

1. Department of Oceanography, Kyungpook National University, Republic of Korea 2. Kyungpook Institute of Oceanography, Kyungpook National University, Republic of Korea 3. Scripps Institution of Oceanography, UCSD, USA 4. Hadley Centre, UK Met Office, UK

Chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs) are all long-lived potent greenhouse gases affecting climate for decades to millennia after being emitted. The radiative forcing reduced by controlling ozone depleting CFCs and HCFCs under the Montreal Protocol (MP) was estimated to be as much as 35% of that of CO2 in 2010 [1]. However, this climate benefit achieved by the MP was considered to be significantly offset by increased use of HFCs with 100-year GWPs ranging from 100 to 14000 as substitutes for CFCs and HCFCs and thus significant future increases in HFC-associated warming. Finally the Kigali Amendment to the MP, which comes into force in 2019, sets schedules for the phasedown of global production and consumption of HFCs. This study presents 9-year, high frequency atmospheric measurement records of major HFCs (HFC-23, HFC-134a, HFC-32, HFC-125, HFC-152a and HFC-143a) obtained at a regional monitoring site in East Asia (Gosan station, Jeju Island, Korea; 33°N, 126°E) from 2008 to 2017. We examine the magnitude and changes of observed pollution events for each HFC compound, and suggest their annual emissions originating from eastern China, the Korean peninsula and western Japan for the period 2008–2017. The emission estimates are made by interspecies correlation method using atmospheric observations of other species measured at Gosan, and by inverse techniques based on NAME–InTEM (Numerical Atmospheric dispersion Modeling Environment–Bayesian Inversion Technique for Emissions Modelling) and on FlexInvert (a Bayesian inversion framework based on the FLEXPART Lagrangian transport model). These ‘top-down’ estimates are compared with country-specific, inventory-based ‘bottom-up’ emission estimates. We also discuss the contributions of country-based, six HFCs’ CO2-eq emissions to the global total and non-Annex I countries’ CO2-eq emissions.

Reference

[1] Velders et al. (2012), Preserving Montreal Protocol climate benefits by limiting HFCs, Science, 24, 335(6071), 922-3, doi: 10.1126/science.1216414.

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GHG Vertical Profiles Measurement Program in the Amazon Luciana Gatti1, John Miller2, Manuel Gloor3, Lucas Domigues4, Caio Correia4, Luciano Marani1, Luana Basso1, Graciela Tejada1, Viviane Borges1, Wouter Peters5, Henrique Cassol6, Stephane Crispim1, Raiane Lopes1, Maisa Ribeiro1, Christiane Morais7, Carlos Aquino7, Dimas Silva1

1. INPE/CCST/LaGEE 2. NOAA/ESRL/GMD 3. University of Leeds 4. IPEN 5. University Groningen 6. INPE 7. Instituto Federal de Rondonia

Amazon is the major tropical land regions and is still been poorly comprehend, with only very few regular greenhouse gas measurements available in the tropics, and mostly not of a suitable nature for estimating carbon balances. Amongst the land regions in the tropics of particular importance for the global carbon cycle is the Amazon, by far the largest region hosting the largest carbon pool in vegetation and soils (~200 PgC). Net carbon exchange between tropical land and the atmosphere is potentially important because it holds large amounts of carbon in forests and soils which can be released on short time-scales e.g. via deforestation or changes in growing conditions, like increased heat and the extension of dry season. Such changes may thus cause feedbacks on global climate. To understand the role of the Amazon in the global carbon balance, we developed a scientific strategy of GHG measures, using small aircraft to perform vertical profiles. The aircraft measurement program was started in 2000 with monthly/biweekly vertical profile sampling at SAN (2.86°S, 54.95°W). From December 2004 to December 2007 we performed vertical profiles at MAN (Dec 2004 / Dec 2007). In 2010, a new step in our program was started. We added three more aircraft sites: TAB (5.96°S, 70.06°W), RBA (9.38°S, 67.62°W) and ALF (8.80°S, 56.75°W). In 2013 TAB site was moved to TEF (3.39°S, 65.6°W) and we add two more aircraft sites with vertical profiles from 300m to 7300 m, at Salinopolis (SAH 0.60°S, 47.37°W) near the Atlantic coast and RBH at the same place then RBA, in the western Amazon to compare with GOSAT. In 2017 we started a new place at Pantanal, the biggest flooded area in Brazil. During this time, until now, it was performed 860 vertical profiles.

References

[1] L.V. Gatti et all, Drought sensitivity of Amazonian carbon balance revealed by atmospheric measurements. Nature, DOI: 10.1038/nature12957, 2014.

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[2] L.S. Basso et al, Seasonality variability of CH4 fluxes from the eastern Amazon Basin inferred from atmospheric profiles. J. Geophys. Res. Atmos., doi. 10.1002/2015JD023874

[3] L.V. Gatti, Vertical profiles of CO2 above eastern Amazonia suggest a net carbon flux to the atmosphere. Tellus DOI: 10.1111/j.1600-0889.2010.00484.x

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[2] L.S. Basso et al, Seasonality variability of CH4 fluxes from the eastern Amazon Basin inferred from atmospheric profiles. J. Geophys. Res. Atmos., doi. 10.1002/2015JD023874

[3] L.V. Gatti, Vertical profiles of CO2 above eastern Amazonia suggest a net carbon flux to the atmosphere. Tellus DOI: 10.1111/j.1600-0889.2010.00484.x

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Background Concentrations of CO2, CO and N2O in Brazilian Coast Luciano Marani1, Viviane Borges2, Luciana Gatti1, Lucas Domingues2, Caio Correia1, Luana Basso1, Ricardo dos Santos1, Stephane Crispim1, Raiane Neves1, Manuel Gloor3, John Miller4 1. Earth System Science Center (CCST), National Institute for Space Research (INPE), São José dos Campos, SP, Brazil 2. Nuclear and Energy Research Institute (IPEN), SP, Brazil 3. School of Geography, University of Leeds, Leeds, UK. 4. Global Monitoring Division, Earth System Research Laboratory, National Oceanic and Atmospheric Administration (NOAA), Boulder, Colorado, USA.

There are fell measures on background greenhouse gases (GHG) in the tropical areas, mainly in the Atlantic Ocean coast. Understand the characteristic GHG concentrations in Tropical Global range on Atlantic Ocean is an important task for many studies to determine GHG balances and the contribution of Amazon area to the regional and global budget. The Amazon Forest represent around 50% of the world's rainforest [1]. To a better understand of the typical GHG background for the Amazon, we presented a study of the concentration of these gases in air masses that arrive on North and Northeast Brazilian Coast in the period of 2006 to 2018. These measurements start in Arembepe (ABP: 12º45’46.79”S; 38º10’08.39”W, 15 meters above sea-level) in 2006 and goes to 2010. Since 2010, we started collect air samples on Salinopolis (SAL: 00º36’15.03”S; 47º22’25.02”W, 10 m a.s.l) and Natal (NAT: 05º29’21.83”S; 35º15’39.42”W, 15 m a.s.l. from 2010 to 2015 and 05º47’43.12”S; 35º11’07.27”W, 87 m a.s.l. since 2015). In 2014, the sampling starts in Camocim (CAM: 02º51’47.00”S; 40º51’36.70”W, 21.5 m a.s.l.). The samples were collected weekly by using a pair of glass flasks (2.5 L) and a portable sampler, totalling 1700 samples. The air samples were analysed to quantify carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), sulphur hexafluoride (SF6) and carbon monoxide (CO) on the Greenhouse Gas Laboratory (at IPEN until April 2015 and later at LaGEE/CCST/INPE). In this work, we present the observations of CO2, N2O and CO at these stations. The results showed that each study site presented seasonality when compared to the WMO GHG Monitoring Global Stations of Ascension Island (ASC: 07º96'67.00"S; 14º0'00.00"W, South Atlantic Ocean) and Ragged Point Barbados (RPB: 13º16'50.00"N, 59º43'20.00"W, North Atlantic Ocean). The stations of SAL and CAM showed highest GHG concentrations between January and May, a behaviour similar to RPB, when the air masses come from North Hemisphere, while in the rest of the year the concentrations were similar to that observed in ASC, when the simulations track their origin in the South Hemisphere. In ABP and NAT the concentrations were lowest and more homogeneous throughout the all year, more similar to ASC, and their origin were tracked only to the South Hemisphere. The influence of the displacement of the Intertropical Convergence Zone (ITCZ) on the GHG concentrations at SAL and CAM was confirmed by backward trajectories simulations by HYSPLIT model (using 240 hours) [2, 3] of the air masses. The

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trends of increase of all GHG concentrations in the Brazilian coast stations showed a similar behaviour of the global average concentrations during the period of this study.

Acknowledgment

CNPq, NERC, FAPESP, MCTIC, NOAA, IPEN and INPE/CCST

References

[1] M. Gloor, et al., The carbon balance of South America: a review of the status, decadal trends and main determinants, Biogeosciences, v.9, p.5407-5430, 2012.

[2] G.D. Rolph. Real-time Environmental Applications and Display system (READY) Website (http://www.ready.noaa.gov). NOAA Air Resources Laboratory, College Park, MD, 2017.

[3] P. Souza, et al., Atmospheric centres of action associated with the Atlantic ITCZ position. International Journal of Climatology, v.29, p.2091–2105, doi: 10.1002/joc.1823, 2009.

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trends of increase of all GHG concentrations in the Brazilian coast stations showed a similar behaviour of the global average concentrations during the period of this study.

Acknowledgment

CNPq, NERC, FAPESP, MCTIC, NOAA, IPEN and INPE/CCST

References

[1] M. Gloor, et al., The carbon balance of South America: a review of the status, decadal trends and main determinants, Biogeosciences, v.9, p.5407-5430, 2012.

[2] G.D. Rolph. Real-time Environmental Applications and Display system (READY) Website (http://www.ready.noaa.gov). NOAA Air Resources Laboratory, College Park, MD, 2017.

[3] P. Souza, et al., Atmospheric centres of action associated with the Atlantic ITCZ position. International Journal of Climatology, v.29, p.2091–2105, doi: 10.1002/joc.1823, 2009.

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Study of long term SF6 mole fractions in Amazon and Brazilian Coast Luana Basso1, Ricardo Santos1, Viviane Borges2, Luciana Gatti1, Caio Correia2, Lucas Domingues2, Luciano Marani1, Stephane Crispim1, Raiane Neves1, Manuel Gloor3, John Miller4 1. Earth System Science Center (CCST), National Institute for Space Research (INPE), São José dos Campos, SP, Brazil 2. Nuclear and Energy Research Institute (IPEN), SP, Brazil 3. School of Geography, University of Leeds, Leeds, UK. 4. Global Monitoring Division, Earth System Research Laboratory, National Oceanic and Atmospheric Administration (NOAA), Boulder, Colorado, USA

SF6 is one of the most potent greenhouse gases known, having a very high global warming potential of 23,500 (relative to CO2), and has a lifetime of 3200 years, so its emissions accumulate in the atmosphere and can be estimated directly from its observed rate of increase [1]. Its global mole fraction was around 9.5 ppt in 2016, almost twice the level observed in the mid-1990s [2]. Since it is a very stable gas in the atmosphere, its annual growth rate has been relatively constant since the 1980s, and has been increasing in a very linear way [3]. Brazil is not an SF6 producer, therefore, the emissions reported in the Brazilian inventory are due only to leaks in equipment installed in the country due to its maintenance or disposal. SF6 atmospheric measurements were started with vertical profiles using small aircrafts, since 2000 in Santarém (SAN; 2.86ºS; 54.95ºW), 2010 in Rio Branco (RBA; 9.38ºS, 67.62ºW), Alta Floresta (ALF; 8.80ºS, 56.75ºW), Tabatinga (TAB; 5.96ºS, 70.06ºW) and Tefé (TEF; 3.31ºS 65.8°W, which started in 2013 to replace TAB, results from these sites will be named TAB_TEF), all these sites located in Brazilian Amazon Basin. In 2006, we started flasks measurements at Arembepe (ABP 12,75°S, 38,15°W; between 2006-2009) located at the Brazilian Atlantic coast, and since 2010 started two more locations, Salinópolis (SAL; 0.60°S, 47.37°W) and Natal (NAT; 5.48°S, 35.26°W). Results of this long-term measurements showed that all sites had a continuous increase in concentrations, with an annual growth ratio between 0.32 and 0.33 ppt/year (2010-2018), that is similar to the global increase in this period (0.32 ppt/year using the NOAA data). Considering only the SAN measurements (2000-2018) the annual growth ratio is 0.28 ppt/year, the same observed for the global mean concentration during this period. These results indicate that Amazon and Brazilian northeast coast do not have significant emissions of SF6 and its concentrations following the global growth ratio.

References

[1] MYHRE, G.; SHINDELL, D.; BRÉON, F.M.; COLLINS, W.; FUGLESTVEDT, J.; HUANG, J.; KOCH, D.; LAMARQUE, J.F.; LEE, D.; MENDOZA, B.; NAKAJIMA, T.; ROBOCK, A.; STEPHENS, G.; TAKEMURA, T.; ZHANG, H., Anthropogenic and Natural Radiative Forcing. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate

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Change. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. 2013. ISBN: 978-1-107-05799-1.

[2] WMO. World Meteorological Organization. Greenhouse Gas Bulletins. The state of greenhouse gases in the atmosphere using global observations through 2017. n.14, 2018. Disponível em: < https://gaw.kishou.go.jp/static/publications/summary/sum42/sum42.pdf>.

[3] KOVÁCS, T.; FENG, W.; TOTTERDILL, A.; PLANE, J.M.C.; DHOMSE, S.; GÓMEZ-MARTÍN, J.C.; STILLER, G.P.; HAENEL, F.J.; SMITH, C.; FORSTER, P.M.; GARCÍA, R.R.; MARSH, D.R.; CHIPPERFIELD, M.P., Determination of the atmospheric lifetime and global warming potential of sulfur hexafluoride using a three-dimensional model, Atmospheric Chemistry and Physics, v.17, p.883–898, 2017. doi:10.5194/acp-17-883-2017. Acknowledgment: FAPESP (2016/02018-2, 2008/58120-3, 2011/51841-0, 2018/14006-4), NASA, ERC (GEOCARBON, Horizon 2020/ASICA), NERC (NE/F005806/1), CNPq (480713/2013-8)

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Change. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. 2013. ISBN: 978-1-107-05799-1.

[2] WMO. World Meteorological Organization. Greenhouse Gas Bulletins. The state of greenhouse gases in the atmosphere using global observations through 2017. n.14, 2018. Disponível em: < https://gaw.kishou.go.jp/static/publications/summary/sum42/sum42.pdf>.

[3] KOVÁCS, T.; FENG, W.; TOTTERDILL, A.; PLANE, J.M.C.; DHOMSE, S.; GÓMEZ-MARTÍN, J.C.; STILLER, G.P.; HAENEL, F.J.; SMITH, C.; FORSTER, P.M.; GARCÍA, R.R.; MARSH, D.R.; CHIPPERFIELD, M.P., Determination of the atmospheric lifetime and global warming potential of sulfur hexafluoride using a three-dimensional model, Atmospheric Chemistry and Physics, v.17, p.883–898, 2017. doi:10.5194/acp-17-883-2017. Acknowledgment: FAPESP (2016/02018-2, 2008/58120-3, 2011/51841-0, 2018/14006-4), NASA, ERC (GEOCARBON, Horizon 2020/ASICA), NERC (NE/F005806/1), CNPq (480713/2013-8)

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Long Term CH4 measurements in Amazon and Brazilian Coast Luana Basso1, Viviane Borges2, Luciana Gatti1, Luciano Marani1, Caio Correia2, Lucas Domingues2, Christiane Morais3, Raiane Neves1, Stephane Crispim1, Manuel Gloor4, John Miller5 1. Earth System Science Center (CCST), National Institute for Space Research (INPE), São José dos Campos, SP, Brazil 2. Nuclear and Energy Research Institute (IPEN), SP, Brazil 3. IFRO, Instituto Federal de Rondonia, Brazil 4. School of Geography, University of Leeds, Leeds LS92JT, UK. 5. Global Monitoring Division, Earth System Research Laboratory, National Oceanic and Atmospheric Administration (NOAA), Boulder, Colorado, USA

Methane is the second most important anthropogenic greenhouse gas, with natural and anthropogenic sources [1]. After a period of CH4 growth rate was near zero, since 2007 the atmospheric CH4 has been increasing again. Until now are not completed understand what factors is causing this increase, but one of possible reasons is an increase in wetlands emissions in tropical areas, like Amazon, due anomalies in precipitation during La Niña events [2, 3]. To improve the understand of the Amazon CH4 balance and the climatic variation effect on this balance, we developed a scientific strategy of GHG measures involving different scales, since local until regional scales, using measures in flasks and small aircraft to perform vertical profiles. The LaGEE activities starting in 2003, constructing a replica of NOAA/ESRL/GMD GHG Laboratory and installing in Brazil in 2004. Since this time the places studied and the types of measures taken have grown to reach our goal. CH4 atmospheric measurements were started with vertical profiles using small aircrafts, since 2000 in Santarém (SAN; 2.86ºS; 54.95ºW), 2010 in Rio Branco (RBA; 9.38ºS, 67.62ºW), Alta Floresta (ALF; 8.80ºS, 56.75ºW), Tabatinga (TAB; 5.96ºS, 70.06ºW) and Tefé (TEF; 3.31ºS 65.8°W, which started in 2013 to replace TAB, results from these sites will be named TAB_TEF), all these sites located in Brazilian Amazon Basin. In 2006, we started flasks measurements at Arembepe (ABP 12,75°S, 38,15°W; between 2006-2009) located at the Brazilian Atlantic coast and since 2010 in more two locations in Brazilian coast, Salinópolis (SAL; 0.60°S, 47.37°W, between 2010-2017) and Natal (NAT; 5.48°S, 35.26°W). In 2014 started another Brazilian coast site, Camocim (CAM; 2.51°S, 40.51°W). Results of this long-term measurements showed that all sites had a continuous increase in CH4 concentrations, with an annual growth ratio between 7.2 and 7.6 ppb/year (2010-2018), that is lower than the global increase in this period (7.8 ppb/year using the NOAA data). Considering only the SAN measurements (2000-2018) the annual growth ratio is 5.8 ppb/year, higher than the observed for the global mean concentration during this period (4.9ppb/year), suggesting higher emissions in this area. Analysing this long time series of SAN is evident the stable period of CH4 concentrations until 2005 and a clear increase in the concentrations after the middle of 2006, following the CH4 global concentration increase.

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References

[1] IPCC Intergovernamental Panel on Climate Change - Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1535 p., 2013.

[2]Dlugokencky, E.; Bruhwiler, L.; White, J.; Emmons, L.; Novelli, P.; Montzka, S.; Masarie, K.A.; Lang, P.M.; Crotwell, A.M.; Miller, J.B.; Gatti, L.V. Observational constrains on recent increases in the atmospheric CH4 burden. Geophysical Research Letters, v. 36, L18803, 2009.

[3]Nisbet, E.G.; Dlugokencky, E.J.; Bousquet, P. Methane on the Rise—Again. Science, v. 343, 2014. Acknowledgment: FAPESP (2016/02018-2, 2008/58120-3, 2011/51841-0, 2018/14006-4), NASA, ERC (GEOCARBON, Horizon 2020/ASICA), NERC (NE/F005806/1), CNPq (480713/2013-8).

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References

[1] IPCC Intergovernamental Panel on Climate Change - Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1535 p., 2013.

[2]Dlugokencky, E.; Bruhwiler, L.; White, J.; Emmons, L.; Novelli, P.; Montzka, S.; Masarie, K.A.; Lang, P.M.; Crotwell, A.M.; Miller, J.B.; Gatti, L.V. Observational constrains on recent increases in the atmospheric CH4 burden. Geophysical Research Letters, v. 36, L18803, 2009.

[3]Nisbet, E.G.; Dlugokencky, E.J.; Bousquet, P. Methane on the Rise—Again. Science, v. 343, 2014. Acknowledgment: FAPESP (2016/02018-2, 2008/58120-3, 2011/51841-0, 2018/14006-4), NASA, ERC (GEOCARBON, Horizon 2020/ASICA), NERC (NE/F005806/1), CNPq (480713/2013-8).

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Observed and simulated urban CO2 behavior around Jakarta megacity Masahide Nishihashi1, Hitoshi Mukai1, Yukio Terao1, Shigeru Hashimoto1, Thomas Lauvaux2, Rizaldi Boer3, Muhammad Ardiansyah3, Bregas Budianto3, Gito Sugih Immanuel3, Adi Rakhman3, Rudi Nugroho4, Nawa Suwedi4, Agus Rifai4, Iif Miftahul Ihsan4, Anies Marufatin4, Albert Sulaiman4, Dodo Gunawan5, Eka Suharguniyawan5, Asep Firman Ilahi5, Muharam Syam Nugraha5, Christian Wattimena5, Bayu Feriaji5, Tomohiro Oda6 1. National Institute for Environmental Studies (NIES), Japan 2. Laboratory for Sciences of Climate and Environment (LSCE), France 3. Bogor Agricultural University (IPB), Indonesia 4. Agency for the Assessment and Application of Technology (BPPT), Indonesia 5. Meteorological, Climatological, and Geophysical Agency (BMKG), Indonesia 6. Universities Space Research Association/NASA Goddard Space Flight Center, USA

The comprehensive monitoring project of GHGs and air pollutants has been maintained in order to quantify anthropogenic emissions from Jakarta megacity in Indonesia, the largest megacity in Southeast Asia, and characterize them in terms of economic activities in the city. To respond to the Paris Climate Agreement, it is important for a monitoring project like ours not only to be capable of monitoring the increasing anthropogenic emissions by rapid economic growth, but also assessing future those reduction impacts resulted from mitigation strategies implemented. We have continuously measured CO2, CH4, CO, NOx, SO2, O3, aerosol concentrations (PM2.5, PM10, BC) and the chemical components (NO3-, SO42-) of PM2.5 and PM10, and meteorological parameters at Bogor (center of Bogor city), Serpong (Jakarta suburb), and Cibeureum (mountainous area, background-like site) since 2016/2017. We have also performed automatic flask sampling once a week. The air samples are used to analyze N2O, SF6, and carbon isotopes (13C, 14C) in CO2 at National Institute for Environmental Studies (NIES) and to validate CO2, CH4, and CO data collected from the continuous measurement. The mole fractions of CO2 observed at the three sites have clear daily daytime variations with the minimum during 12 to 15 local time. The average daytime CO2 values observed at Bogor and Serpong from June 2017 to February 2019 were 7.7 and 6.3 ppm higher than Cibeureum, respectively. We found that the daytime CO2 differences decreased to 4.5 ppm at Bogor and 1.6 ppm at Serpong in January, which is the mid-rainy season around Jakarta, in 2018 and 2019. In these time periods, relatively-strong westerly wind was dominant throughout the day and it might weaken the accumulation of urban CO2 near the surface. We have conducted high-resolution atmospheric CO2 simulations using the Weather Research and Forecasting model coupled to Chemistry (WRF-Chem). We used two emission inventories to prescribe the surface emissions: ODIAC (Open-source Data Inventory for Anthropogenic CO2) as fossil fuel CO2 and MsTMIP (Multi-scale Synthesis and Terrestrial Model Intercomparison Project) as biogenic CO2. The simulated temporal CO2 variations at three monitoring sites are reasonably consistent with the observation in the dry season. However, the simulated CO2 at Serpong was

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higher than the observed values in the mid-rainy season possibly due to the poor reproducibility of meteorological fields. Nevertheless, the observed unique characteristics of lower concentration in the mid-rainy season were replicated in the simulation. In our presentation, we will also present the relationship between CO2 and the other species.

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higher than the observed values in the mid-rainy season possibly due to the poor reproducibility of meteorological fields. Nevertheless, the observed unique characteristics of lower concentration in the mid-rainy season were replicated in the simulation. In our presentation, we will also present the relationship between CO2 and the other species.

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MExico city’s Regional Carbon Impacts (MERCI-CO2): combining high precision surface monitoring, with low-costs sensors, and total column measurements Michel Ramonet1, Michel Grutter2, Maria Eugenia Gonzalez2, Beatriz Cardenas3, Samya Pinheiro4, Yang Xu1, Francois-Marie Bréon1, Wolfgang Stremme2, Agustin Garcia2, Noemie Taquet2, Alejandro Bezanilla2, Olivier Laurent1, Marc Delmotte1, Morgan Lopez1, Patricia Camacho3, Félix Vogel5, Philippe Ciais1 1. LSCE, Institut Pierre Simon Laplace, Université Paris-Saclay, CNRS/CEA/UVSQ, Gif Sur Yvette, France 2. Centro de Ciencias de la Atmósfera, Universidad Nacional Autónoma de México, Circuito de la Investigación s/n,Ciudad Universitaria, 04510 México, D.F., México 3. Secretaría del Medio Ambiente del Gobierno de la Ciudad de México, Plaza de la Constitución Nº 1, 3er Piso, Col. Centro, C.P. 06068 Del. Cuauhtémoc, Ciudad de México 4. ARIA do Brasil, Largo de Machado, 21, sala 502 – Catete CEP 22221-020, Rio de Janeiro, Brasil 5. Climate Research Division, Environment and Climate Change Canada, Toronto, Canada

Mexico City (MC) is the home of 21.2M people, with intense emissions of pollutants and greenhouse gases, which accumulate in the overlying air-shed due to the location of the city in a basin surrounded by mountains. Local authorities have engaged in emission reduction activities. The purpose of the French-Mexican project MERCI-CO2 is to set up atmospheric CO2 measurements and analysis tools that will permit the verification of CO2 emission reductions. As part of this project we shall measure atmospheric CO2 concentrations gradients within and around MC, attribute them to emissions from the city, and combine them with an atmospheric transport model and emission inventories to reduce the uncertainty on CO2 emissions in support of reduction policies taken by regional authorities. Given the huge extent of MC, sampling the atmosphere to best capture its CO2 emissions is a scientific challenge, which requires several monitoring stations. The proposed solution is to deploy an array of 10 novel low-cost medium precision (LCMP) CO2 sensors with two high-precision instruments. The locations of LCMP will be selected after analysis of existing air quality observations and gridded CO2 emissions fields. Combining CO2, CO and NOx observations will help us to identify the contribution of different emission sectors (traffic, residential, industry). CO2 concentrations measured in the boundary layer will be complemented by total air column observations. These measurements will characterize large-scale CO2 gradients between upwind and downwind of MC, providing an independent check of total city emissions, and a bridge to satellite observations of the CO2 column. Both measurements will be compared to simulations from a high-resolution model prescribed with city-scale CO2 emission maps. The inversion of selected CO2 gradients in an analytical Bayesian inversion framework will allow estimating MC emissions, which will be compared to the existing official inventory (based on energy use and fuel statistics).

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Characterising Methane Emissions using a Twin-Otter Airborne Platform

James France1,2, Dave Lowry1, Rebecca Fisher1, Max Coleman1, Euan Nisbet1, Tom Lachlan-Cope2, Anna Jones2, Alexandra Weiss2, Stephane Bauguitte3, Grant Allen4, Prue Bateson4, Jacob Shaw4, Joe Pitt4, Langwen Huang4, Steve Andrews5, Pamela Dominutti5, James Lee5, Stuart Young5

1. Royal Holloway University 2. British Antarctic Survey 3. Facility for Airborne Atmospheric Measurements 4. University of Manchester 5. University of York, National Centre for Atmospheric Science

In the last 18 months, the British Antarctic Survey (BAS) Twin-Otter aircraft has been adapted to allow installation of an instrument suite for Greenhouse Gas measurement. Although the range of the twin otter is relatively poor compared to other research aircraft, such as the UK FAAM BAE-146 (a small 4-engine jet), it is slower and more manoeuvrable allowing for better targeting of plumes. The Twin-Otter has been the instrument platform for two recent campaigns: 1) As part of the UN CCAC (Climate and Clean Air Coalition) international methane studies, a five-day aircraft campaign using the BAS Twin Otter aircraft was conducted in the southern North Sea in April 2018 and April/May 2019, and 2) As part of the UK’s MOYA (Global methane budget) program, tasked with investigating methane emissions from wetlands in Bolivia. For the North Sea study, the set-up used a combination of C2H6, CH4, CO2 continuous measurement (~1Hz) using cavity enhanced spectroscopy, and discrete whole air samples collected in emission plumes and analysed in the laboratory for δ13C-CH4 using high precision CF-GC-IRMS (Continuous Flow – Gas Chromatography/Isotope Ratio Mass Spectrometry). In the Bolivian campaign the C2H6 capability was not fitted. The combination of measurement techniques allows identification and distinction between emission sources using δ13C-CH4 and C2H6:CH4 as signatures for varying sources of emission. These chemical and isotopic signatures enable sources of emissions to be identified. Variability in these signatures potentially will help in identifying specific emission processes (e.g. flaring vs leaking gas) and further characterisation of specific sources (e.g. ratios of C3 vs C4 inputs in tropical wetlands and adjacent biomass burning). Emissions from specific sites in the North Sea have been identified from the April 2018 campaign, with enriched δ13C-CH4 or elevated C2H6 from CH4 plumes indicating oil and gas infrastructure as most likely sources. Targeted sampling in the 2019 North Sea campaign enabled testing of the temporal consistency of the emissions and their δ13C-CH4 and C2H6:CH4 signatures. Wetland emissions from Bolivia, made at the end of the rainy season, appear to be very large and have an isotopic source signature more negative than anticipated (i.e. perhaps richer in C3 plant carbon?). A simple mass-balance approach is being taken to give an approximation of the regional flux of methane.

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P62


Characterising Methane Emissions using a Twin-Otter Airborne Platform

James France1,2, Dave Lowry1, Rebecca Fisher1, Max Coleman1, Euan Nisbet1, Tom Lachlan-Cope2, Anna Jones2, Alexandra Weiss2, Stephane Bauguitte3, Grant Allen4, Prue Bateson4, Jacob Shaw4, Joe Pitt4, Langwen Huang4, Steve Andrews5, Pamela Dominutti5, James Lee5, Stuart Young5

1. Royal Holloway University 2. British Antarctic Survey 3. Facility for Airborne Atmospheric Measurements 4. University of Manchester 5. University of York, National Centre for Atmospheric Science

In the last 18 months, the British Antarctic Survey (BAS) Twin-Otter aircraft has been adapted to allow installation of an instrument suite for Greenhouse Gas measurement. Although the range of the twin otter is relatively poor compared to other research aircraft, such as the UK FAAM BAE-146 (a small 4-engine jet), it is slower and more manoeuvrable allowing for better targeting of plumes. The Twin-Otter has been the instrument platform for two recent campaigns: 1) As part of the UN CCAC (Climate and Clean Air Coalition) international methane studies, a five-day aircraft campaign using the BAS Twin Otter aircraft was conducted in the southern North Sea in April 2018 and April/May 2019, and 2) As part of the UK’s MOYA (Global methane budget) program, tasked with investigating methane emissions from wetlands in Bolivia. For the North Sea study, the set-up used a combination of C2H6, CH4, CO2 continuous measurement (~1Hz) using cavity enhanced spectroscopy, and discrete whole air samples collected in emission plumes and analysed in the laboratory for δ13C-CH4 using high precision CF-GC-IRMS (Continuous Flow – Gas Chromatography/Isotope Ratio Mass Spectrometry). In the Bolivian campaign the C2H6 capability was not fitted. The combination of measurement techniques allows identification and distinction between emission sources using δ13C-CH4 and C2H6:CH4 as signatures for varying sources of emission. These chemical and isotopic signatures enable sources of emissions to be identified. Variability in these signatures potentially will help in identifying specific emission processes (e.g. flaring vs leaking gas) and further characterisation of specific sources (e.g. ratios of C3 vs C4 inputs in tropical wetlands and adjacent biomass burning). Emissions from specific sites in the North Sea have been identified from the April 2018 campaign, with enriched δ13C-CH4 or elevated C2H6 from CH4 plumes indicating oil and gas infrastructure as most likely sources. Targeted sampling in the 2019 North Sea campaign enabled testing of the temporal consistency of the emissions and their δ13C-CH4 and C2H6:CH4 signatures. Wetland emissions from Bolivia, made at the end of the rainy season, appear to be very large and have an isotopic source signature more negative than anticipated (i.e. perhaps richer in C3 plant carbon?). A simple mass-balance approach is being taken to give an approximation of the regional flux of methane.

P63


The Aircore system and campaign for vertical profile measurements of greenhouse gases in China

Miao Liang1, Shuangxi Fang1, Bo Yao1

1. CMA

Accurate measurement of the vertical distribution of CO2 in the atmosphere are critical to validate columns recorded by satellite and the ground-based spectrometers and to estimate sources and sinks of CO2. An original sampling system called AirCore has been developed at NOAA for vertical profile of atmospheric CO2 (Karion et al. 2010). A balloon-borne sampling system adopting this technique was developed and field-tested by MOC (Meteorological observation center), CMA. The sampler used in this study is a 150-m-long stainless steel tube (150 m 1/8 in. and 50 m 1/4 in. as one) with one end open and the other closed. It relies on passively collecting air using the atmospheric pressure gradient during descent. It is sealed immediately after landing and measured by a cavity ring-down spectrometer (CRDS) for CO2 upon recovery. Measurements of CO2 mole fractions in laboratory tests indicate a repeatability of 0.08×10-6 and bias to better than 0.06×10-6 (1σ) for CO2 under various conditions. For field experiment, the tubing is combined with sensor system and wireless receiver, transmitter. The altitude attribution of mixing ratios for each sampled air can be retrieved on the basis of the ideal gas law and the molar amount sampled at each altitude during the flight. Field campaigns were conducted for the first time on Nov. 22th and 23th, 2018 in Urad Middle Banner. Vertical profiles of CO2 up to 25 km were successfully retrieved. The vertical resolution with our configuration was determined to be 600 m up to 10 km and better than 3.3 km up to 2 km respectively. The system provides an in situ and low-cost method of greenhouse gas measurements for validation of satellite data and estimation of regional flux.

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