Ground-Based Measurements and Campaign Database Subgroup

Envisat Validation Workshop, ACVT-GBMCD, Approach and Objectives 12/12/2002

Ground-Based Measurements and Campaign Database SubgroupAgenda

09:00 Approach, objectives and status 09:20 Campaign databaseGOMOS Validation 09:40 Comparison of density and temperature

profiles 10:00 Comparison of ozone profiles 10:45 Analysis of altitude registration (11:00 Coffee/Tea)MIPAS Validation 11:15 Comparison of pressure, temperature and water vapour profiles 11:30 Comparison of ozone profilesSCIAMACHY Validation 11:45 Comparison of NRT O3 and NO2 columns 12:25 Comparison of other operational products

12:40 Comparison of scientific products12:55 Conclusions


Envisat Validation Workshop

Atmospheric Chemistry Validation Team

Ground-Based Measurements and Campaign Database Subgroup

Approach, Objectives and Status

[email protected]


Campaign Database: Objectives

Provide access for validation analysis teams to correlative data in a homogeneous manner Facilitate collocation, selection

Campaign Database: Approach

Meta data standard Uniform format Centralised database Dedicated query interface

STATUS: see presentation T. Krognes


Ground-based Measurements: Objectives

Acquire a large set of correlative data, with closest possible collocation, covering a wide range of conditions

Analyse individual intercomparisons to identify artifacts

Perform comprehensive analysis of the subgroup dataset in order to:

formulate a statistically-relevant quality assessment.characterise deviations (detect dependencies).

Formulate recommendations for improvements


GBM: Approach (1/4) : Investigator Team


GBM: Approach (2/4) Investigator Team19 AOID/Principal Investigators126/De Mazière153/Pal158/Lambert174/Kelder179/Matthews191/Blumenstock206/Visconti222/Fricke300/De Muer331/Burrows360/Keckhut427/Timofeyev429/Kyro632/Ciotti1103/Petritoli9003/Swart9079/Hansen9083/Cuomo9100/Congedutti

Numerous Co-Investigators from the following Institutes:

AWI, BAS, BIRA-IASB, CNES, DLR, DMI, DWD, ETH-Honggerbergh, FHG, FMI, FZ Karlsruhe IMK and IFU, FZ. Juelich, IFE/U. Bremen,

IMAA, IMAU, IMP, IMWM, INM, INTA, IRF, ISAC-CNR, IVL, JPL TMF, KNMI, KTSU, LPA, Univ.

Reunion, LPMA/CNRS, MCH, MPI Otto Hahn, MSC, NASA GSFC and LaRC, NILU, NIWA, NIWI, NPL,

Phys.Inst. Univ. Bonn, RAL, RIVM, RMI, SA/CNRS, SRON, STEL, Nagoya Univ., SAAI, St.

Petersburg State Univ., Swedish Inst. of Space Physics, U. Athene, U. Bern, U.

Bordeaux, U. Reims, U. Wales, U. Denver, UNESP, U. La Sapienza, U. of Heidelberg, U

of l'Aquila, U. of Liege, U. of Thessaloniki, U. of Wollongong, York Univ. and support from the WMO/GAW and the NDSC

GBMCD direct information exchange: 92 team members


GBM: Approach (3/4) Correlative Data AcquisitionA suite of different instruments is deployed in order

to confront Envisat data with fully independent retrievals, covering various

Spectral ranges, Fields of view/sampling volumesRetrieval methodsDegrees of sensitivity to diurnal variations, Non-LTE effects, pollution, etc.

Observations have been performed at a large number of sites in order to cover variations as a function of:

geophysical and climatological conditions that vary with latitude/longitude season (2 hemispheres)

Frequent measurements have been performed in order to obtain statistical significance.


GBM: Approach (4/4) Analysis

•Correlative data and interim results are exchanged via two centralised archives among all the subgroup members in order to obtain comprehensive results

•Validation results are exchanged with the Verification Teams

•An inventory of collocated Envisat observations is maintained in order to set

(re)processing priorities


Status (1/3): Data Acquisition

Statistics on the observations available so far: 460 by Lidar, 219 by MWR, 1702 by O3 and radio sondes and SAOZ balloons, 552 by spectro/photometers and 1347 UV-VIS instruments, 397 by FTIR instruments, and 111 by other instruments at Arctic (7%), Northern Mid Latitudes (70%), Tropics (17%), Southern Mid Latitudes (4%), Antarctic sites (2%) (72 sites in total) up to a total of 4743 observations to date.

Several opportunities could not be used due to late availability of overpass tables.

The inventory of data acquired is not yet complete.


Status (2/3): Envisat Data Availability

Collocated GOM_NL__2P data for about 300 GBMCD observations are available from the GOMOS ESL.

For MIP_NL__2P, only recent collocations (November) are available

For SCIAMACY, frequent collocated SCI_NL__2P products are available for only recent observations (November), plus a few earlier collocations from the CDs.

Additional collocations are available for Ozone, from MIPAS and SCIA Meteo Data.

Generally G/M/S data are available for 5% of the collocated ground-based measurements.


Status (3/3): Validation Analysis

Late availability of only sparse datasets has delayed analysis activities.

Only a preliminary analysis could be performed on a few collocations per instrument.

Preliminary indicative results have also been derived from the global dataset (see following presentations).

Quantitative global validation is still to begin.


Issues raised during initial analysis

Processing of unprocessed historic data, and reprocessing of data processed with older versions are urgently needed in order to obtain a single homogeneous dataset covering the Commissioning-Phase collocations.

For any data product, the contribution of retrieved data versus external information should be specified (e.g. SCIA CTH is currently 100% climatologic, GOMOS L-R Temperature partially).

A processing modification history should be supplied with the Envisat products.

Currently, Envisat information sources (sites) are rather dispersed.

Ground-Based Measurements and Campaign Database Subgroup

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