stephane CALMANT (IRD / LEGOS, France); Otto CORREA ROTUNO FILHO (UFRJ / COPE, Brazil); Felix PEROSANZ (CNES / GET, France)

Since the study by Hall et al. (2011), no other study focused on the validation of the ICESAT data over rivers such as the Amazon river. In the latter study, authors compared the ICESAT data with the water levels of in-situ gauges. Yet, the results were quite disappointing, showing large errors of several tens of cm.
In the present study, we also compare the ICESAT data to gauge series but in addition, we made a prelinminary quality check of the series, GPS levelled the gauges and most important, accounted for the slope of the water surface using longitudinal GPS profiles of the water surface collected on the rivers.
Our results, based on the processing of 445 ICESAT passes, show that the RMS difference between the ICESAT measurements and the in-situ weter levels range between 2 to 17 cm, depending on the gauge considered.
Consequently, the ICESAT data can be used with confidence for many applications in the management of large bassins, such as gauge levelling, check of gauge series, gap filling in altimetry series; and we present examples of such uses.

Hall et al., 2011; Geodetic corrections to Amazon River water level gauges using Icesat altimetry, WRR, doi:10.1029/2011WR010895