Improvements of GDP Level 0-1 Processing software in the framework of CHEOPS-GOME
Sander Slijkhuis(1), Bernd Aberle(1) and Diego Loyola(1)
(1) German Aerospace Centre, DLR-IMF Oberpfaffenhofen, 82234 Wessling, Germany
Over more than 10 years, the ERS-2/GOME Data Processor (GDP) has generated operational Level 1 data products with sufficient accuracy to obtain total column retrievals of Ozone and other trace gases, with high quality. As scientific algorithms were developed to perform retrieval of height-resolved Ozone profiles from GOME data, it became apparent that the standard GDP Level 1 product needed improvements, to cope with the enhanced requirements on instrument calibration posed by profile retrieval.
In the framework of the project CHEOPS-GOME, "Climatology of Height-resolved Earth Ozone and Profiling Systems for GOME", ESA has undertaken an effort to incorporate the necessary improvements in GOME calibration in the official Level 1 data. This will be achieved by changes in the GDP Level 0 to 1 Processing software.
In this paper we will describe the changes arising from the CHEOPS study, which comprise:
- background correction in band 1a
- azimuth dependence of the Sun diffuser BSDF
- correction of degradation in reflectivity, using a LUT generated by SRON
- improved polarisation correction, based on an algorithm used in KNMI's GomeCal software.
It is envisaged to reprocess the complete GOME Level 1 data record with the improved algorithms (containing also improvements in wavelength calibration, not covered by this study),and to disseminate the updated GOME Level 1 products, via FTP, in summer 2006.
Keywords: ESA European
Space Agency - Agence spatiale europeenne,
observation de la terre, earth observation,
satellite remote sensing,
teledetection, geophysique, altimetrie, radar,
chimique atmospherique, geophysics, altimetry, radar,