Cryosat LRM processing over Antarctica
Blumstein, Denis1; Flament, Thomas2; Boy, Francois3; Desjonqueres, Jean-Damien3; Legresy, Benoit2; Remy, Frederique2; Picot, Nicolas3; Femenias, Pierre4
1CNES, LEGOS, UMR5566 CNRS-CNES-IRD-Université de Toulouse III, FRANCE; 2CNRS, LEGOS, UMR5566 CNRS-CNES-IRD-Université de Toulouse III, FRANCE; 3CNES, Centre Spatial de Toulouse, FRANCE; 4ESA, ESRIN, ITALY

Like for all past ESA missions (ERS1&2, ENVISAT) the CryoSat altimeter LRM mode is used over major part of the ice sheet. For these past missions, several ground-retracking solutions were implemented in the ESA ground processing system. For example on ENVISAT, 4 different retracking solutions are available in parallel, providing very valuable information. The ice2 retracking estimates were extensively analyzed by our group and we were able to derive empirical corrections models to account for the electromagnetic interaction with the ice. Those corrections have proved to largely increase the data quality and they might be implemented into future ENVISAT reprocessing campaigns performed by ESA. For the CryoSat mission, the ESA L2 products include today the ice1 (MSSL) retracking and the MLE3 ocean solution inherited from ENVISAT. The ice2 retracking, developed by LEGOS, is not available for the user community. In order to analyze the results from this retracking algorithm, LEGOS, with the support from CNES, has implemented this retracking solution on the CryoSat ESA L1B products. In addition, recent works based on a numerical retracking model (using digital elevation model and multi layer approach) have been implemented in the CPP_ice prototype (Cryosat Processing Prototype implemented by CNES) . We will compare the retracking estimates between the different retracking solutions, focusing on specific area like the Dome A, Dome C and Vostok and we will present the waveform fit between the altimeter waveform acquired and the one simulated with our numerical mode. In addition, analysis of differences at crossover points will presented. Finally, first comparisons with the SARAL Ka altimeter data will be presented.