At what spatial and temporal scales do we gain useful information from stable water isotope observations?

Harald Sodemann Geophysical Institute, University of Bergen and Bjerknes Centre for Climate Change, Bergen, Norway

SNOWPACE

With acknowledgements to Yongbiao Weng, Mika Lanzky, Alexandra Touzeau, Lukas Papritz, Alexander Läderach,

Astrid Fremme, Andrew Seidl

CLIVAR-US Water Isotopes and Climate Workshop, Boulder, 1-3 Oct 2019

Revised and evolving concepts

Towards a dynamic view on moisture transport

Luetscher et al., 2015

A weather system perspective

Sodemann and Stohl, 2009Winschall et al., 2014

Antarctica, MAM

Mediterranean HPEs

Moisture life time distributions

Sodemann, 2019, revisedthis work,

this work,

this work,

this work,

this work,

this work,

this work,

this work,

(a) (b)8.5 days 8.5 days

Targeting local water cycles

Papritz and Sodemann, MWR, 2018

Image ©: MODIS on Aqua, NASA Worldview

0-12h 12-24h24-36h

36-48h

48-60h

60-72h

72-84h

CAOSvalbard

CAO

AR

Irminger Sea

Fram Strait

Iceland

Norwegian Basin

Measurement opportunities: going in-situ

Disentangling different processes from measurements and modelling

HD16O

H218O

Sodemann et al., 2008

evaporation

mixing

mixed-phasemicrophysics

precipitationH217O

Deuterium excess

17O excess

below-cloud

post-deposition

transport

Interpretation framework: equilibrium vapour

Aemisegger et al., GRL, 2015

liquid phase

vapour phase

αl→v

Interpretation framework: ! diagramΔδ − Δd

Graf et al., ACP, 2019

Measurements during the IGP campaign as part of SNOWPACE, March 2018

Akureyri

R/V Alliance

BAS Twin Otter

Husavik

Husavik

δ18O in snow and vapour

d-excess in snow and vapour

Isotope measurement platforms and procedures

LaboratoryShip

Reliability and intercalibrationSharing tools and routines

Ultralight Aircraft Icebreaker KV Svalbard

High-resolution precipitaiton sampling

Yongbiao Weng et al., in prep.

Landfalling AR in southern Norway, Dec. 2016

A citizen science campaign with sample return

• Information

• Preparing snow kits

• Sample kit distribution

• Distributing snow kits

• Arranging sample return

• Analysis and interpretation

• Communication

Snapshot sampling and Citizen science snow samplingδD / permil

~ -20 permil / ° longitude

PhD Mika Lanzky

Spatial representativeness

Networks of stable isotope measurement stations

Moisture sources for Bergen during 2013 (10-3 mm day-1)Nov Dec Jan Feb Mar Apr

Num

ber o

f CAO

day

s

0

5

10

15

20

25

b)a) 30

Bergen

Bergen

Reykjavik

Reykjavik

Svalbard

Svalbard

ISLAS: plans for evaporation fieldwork in Ny ÅlesundSpring 2020 (during MOSAiC)

Field-deployable unit for isotopemeasurements during evaporation

PhD Andrew Seidl

aircraft campaign, Longyearbyen, March/April 2021

AWI Polar 5/6

Flight patterns • Lagrangian flight experiments• Survey flights• Cloud profiles• Evaporation (low-level)

1st priority: CAO (Cold-air outbreaks) 2nd priority: ARs (Warm air intrusions)

Day 1

Day 2

Day 3 PhD Aina Johannessen

Isotope-enabled regional models as "gold standard"

COSMOisoMARICONWRF

AROME…

Pfahl et al., 2012

ParameterisationsError compensation

ObservationsRepresentativeness

Better global models due to stable isotopes

THEME ”GLOBAL CLIMATE”

Massflux conservation within CAM5/NorESMNorESM with stable water isotopesStable water isotope coupling across components

BCCR subgroup "Water cycle and water isotopes"

Perspectives on the water cycle are evolving - moisture sources vary with weather systems - the lifetime of precipitation has a highly skewed distribution

Spatial representativeness is a prerequisite for model-observation comparisons.

Information contained at short time scales for precipitaiton

Intercomparison of measurements and sharing of methods is key

Forthcoming campaigns will allow to consider the coupling between the components of the water cycle

Regional and global models constrained by stable isotope observations can act as gold standard and progress into operational reach

Conclusions

FARLAB

Instrumentation, domain, forecasts and planning tools

ISLAS campaign period and domainMarch/April 2021 (ca. 3 weeks)Longyearbyen/Tromso/Bjørnøya

Forecasting and flight planning toolsCOSMO-tagging forecastsAROME tendency diagnosticsAROME-Arctic ensembleFLEXPART airmass tagging forecastsMET.3D Virtual Reality visualisationContacts to Met Norway in Tromø

InstrumentationPicarro L2130-i analyzer for water vapour isotopes (1 Hz) with heated inletCloud ice/water sampling with freeze drying unitPTUCloud probesAerosols?

Additional observationsGround-based vapour measurementsGround-based precipitation samplingShip-based measurements?

Simulations with tracer-enabled limited area model COSMOtag

Evaporation masks for CAO tracers: θSST – θ900 > 4 K

Release windows for tracers

Secondary water cycle representing water picked up by CAO air mass via ocean evaporation Winschall et al. 2014, Sodemann et al. 2009

Papritz and Sodemann, MWR, 2018