INVESTIGATION ON THE ELEVATION DIFFERENCE BETWEEN ICESAT AND ENVISAT AT CROSSOVER POINTS AND BENEFITS FROM SARAL/ALTIKA FOR ICE SHEETS

摘要

Satellite altimetry is the most performant toolrnto study ice sheets as it has very dense spatial and timerncoverages. Since 1991, ERS1, ERS2 and Envisatrnsurveyed ice sheets in Ku-band. In 2013 was launchedrnthe joint-mission between CNES and ISRO (IndianrnSpace Agency) called SARAL with the AltiKa altimeterrnonboard. This mission is the first one to use Ka-band,rnwith a finer vertical resolution, a better sampling, a lessrnvolume echo as suggested by the theory. Moreover itrnhas the same repeat track as Envisat and the ERS seriesrnso we can compare between them by taking into accountrntheir differences.rnIn this paper, we show preliminary results from all therncomparisons performed between Envisat and Saral.rnIndeed more cycles from Saral are needed to confirm orrninfirm our observations but the raising challenges arernnumerous and promising to understand the Ka-band asrnwell as the Ku-band but also the interaction between thernradar wave and the snowpack in order to link withrngeophysical properties.