The Use and Usability of Satellite Data for Tropospheric Research
Task Group 4 Task Group 4
Development of Validation Strategies for Tropospheric Satellite Data Products
Task Group Leader
Hennie Kelder, KNMI, de Bilt
Task Group 4 Principal Investigators
Strategies proposed for the validation of tropospheric satellite data products include:
- comparison of measurements (ground-based, aircraft, and satellites) with models;
- analysis of different retrieval methods and measuring techniques;
- use of data assimilation methods.
Validation activities are envisaged for the following data sources.
- Output from the ENVISAT instruments, SCIAMACHY, MIPAS and GOMOS.
- Ozone sonde data from the NILU/NADIR data base
- Long term NO2, ozone, SO2, and aerosol measurements from the EMEP data base.
- Aircraft measurements from CARIBIC, the M-55 Geophysica, and MOZAIC.
The novel algorithms allowing the observation of tropospheric composition from space require thorough testing and verification and so strategies for the geophysical validation of tropospheric satellite data products need to be developed and applied. Strategies proposed are: collection of comparative measurements (ground-based, aircraft, and other satellite measurements); intercomparison of these measurements with the satellite data; comparison of the satellite data with model results; analysis of different retrieval methods; analysis of different measuring techniques; use of data assimilation methods.
Among the validation activities envisaged are the following.
- Validation of the tropospheric output from the ENVISAT instruments, SCIAMACHY, MIPAS and GOMOS.
- Improved strategies for validation envisaged for comparison of satellite data must take into account the different vertical resolution, averaging kernels and viewing geometries of the technique used for validation and the satellite instrument.
- Ground-based data to be used for validation will include the ozone sonde data available from the NILU/NADIR data base for ozone in the free troposphere, the long term NO2, ozone, SO2, and aerosol measurements available in the EMEP data base. This will be combined with inverse modelling activities. Comparisons are also proposed involving, FTIR measurements, with a focus on the tropospheric trace species O3, CO, CH4, N2O, and H2O.
- The validation comparisons with aircraft measurements will include those produced from the EC project, CARIBIC, data from the high-altitude aircraft M-55 Geophysica, and the MOZAIC data. Other comparisons will deal with radiation budgets and albedo estimates, aerosols, scattering coefficients, and concentration profiles of HCHO and CO.
- Attempts at validation using model results include comparing the SCIAMACHY CO and CH4 tropospheric columns with results from the 3D chemistry transport model, TM3. The MOPITT CO and CH4 data will be compared with the Oslo University GCM model.