Evaluation of the SENTINEL-3A water levels over large hydrological basins

Stéphane Calmant (IRD, France)

CoAuthors

Denis BLUMSTEIN (CNES / LEGOS, FRANCE); Joecila SANTOS da SILVA (CESTU / UEA, BRAZIL); Adrien PARIS (CLS, FRANCE)

Event: 2017 Ocean Surface Topography Science Team Meeting

Session: Science IV: 25 years of satellite altimetry for Cryosphere and Hydrology: from experimental to emerging operational applications

Presentation type: Type Poster

SENTINEL-3A, was launched in early 2016 by ESA. Its altimeter is expected to collect water levels in SAR mode in the Ku EM band over the great majority of hydrological basins. In the present study, we evaluate the performance of this new mission in providing valuable water levels over the two major basins on Earth, namely the Amazon and Congo Basins.
Since the launch, the SENTINEL-3A altimetry data have been distributed in a variety of versions. We processed the LAN data in version 1.2 for cycles >= 17 and version 1.5 for cycles up to 16, reprocessed consistently with version 1.2.
For this analysis, we identified 465 sites in the Congo basin and 1140 sites in the AMAZON basin where SENTINEL-3A groundtracks cross the river network and can potentially collect water levels. Note that some of these sites are included in the onboard DEM mask when others are not.
Since almost no gauge is maintained by the national agencies in the Congo basin, we installed two automatic gauges for the validation of the SENTINEL-3A measurements, right under orbit groundtracks. Similarly, we installed gauges in the Amazon basin in order to complement the national network of gauges maintained by Brazil.
We present preliminary assessments of the amount of data collected, or missing, the RMS difference with gauge readings and the absolute bias, for both the OCEAN and OCOG range retracking algorithms.
 

Poster show times:

RoomStart DateEnd Date
Concerto Ballroom Thu, Oct 26 2017,14:00 Thu, Oct 26 2017,18:00
Stéphane Calmant
IRD
France
stephane.calmant@ird.fr