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 tool to study ice sheets as it has very dense spatial and time coverages. Since 1991, ERS1, ERS2 and Envisat surveyed ice sheets in Ku-band. In 2013 was launched the joint-mission between CNES and ISRO (Indian Space Agency) called SARAL with the AltiKa altimeter onboard. This mission is the first one to use Ka-band, with a finer vertical resolution, a better sampling, a less volume echo as suggested by the theory. Moreover it has the same repeat track as Envisat and the ERS series so we can compare between them by taking into account their differences. In this paper, we show preliminary results from all the comparisons performed between Envisat and Saral. Indeed more cycles from Saral are needed to confirm or infirm our observations but the raising challenges are numerous and promising to understand the Ka-band as well as the Ku-band but also the interaction between the radar wave and the snowpack in order to link with geophysical properties.