10-Years Operational GOME/ERS-2 Total Column Products: The GDP 4.0 Validation
Dimitris Balis(1), Jean-Christopher Lambert(2), Michel Van Roozendael(3), Robert Spurr(4), Diego Loyola(5), Yakov Livschitz(5), Pieter Valks(5), V. Amiridis(1), P. Gerard(3), J. Granville(3) and Claus Zehner(6)
(1) Aristotle University of Thessaloniki, Box 149, 54124 Thessaloniki, Greece
(2) BIRA, Avenue Circulaire 3, 1180 Bruxelles, Belgium
(3) BIRA, 3 Avenue Circulaire, B-1180 Brussels, Belgium
(4) RT Solutions, Inc., 9 Channing Street, Cambridge MA 02138, United States
(5) DLR, Oberpfaffenhofen, D-82234 Wessling, Germany
(6) ESA, Via Galileo Galilei CP. 64, 00044 Frascati, Italy
Results of a geophysical validation exercise regarding the new operational GOME data processor (GDP4.0) are presented. This exercise involves comparisons with NDSC and WMO/GAW ground-based networks as well as with the TOMS version 8 total ozone products.
For GOME, RMS values have improved by a factor of two compared with GDP 3.0; seasonal dependency is reduced by the same amount. On a global basis, GDP 4.0 total ozone results lie between -1% and +1.5% of ground-based values for solar zenith angles less than 70°; accuracy is now comparable to that obtainable from ground based stations. At higher solar zenith angles in Polar Regions, larger discrepancies of up to +4% are found; in these regimes, errors on both satellite and ground-based measurements are higher.
Up to 2003, total column products have not suffered from any long-term drift of quality, even with expected instrument degradation.
The validation results demonstrate that the re-processed GOME total ozone record is now sufficiently accurate for trend analysis (detection of 1% change in total ozone over 10 years).
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,