Abstract's details
Regional in situ CalVal of Sentinel-3A&B altimeter range at non-dedicated sites
CoAuthors
Event: 2022 Ocean Surface Topography Science Team Meeting
Session: Regional and Global CAL/VAL for Assembling a Climate Data Record
Presentation type: Type Poster
Contribution: PDF file
Abstract:
In situ calibration ensures regular and long-term control of the altimeter sea surface height (SSH) time series through comparisons with independent records. Usually, in situ calibration of altimeter SSH is undertaken at specific CalVal sites through the direct comparison of the altimeter data with in situ data.
However, Noveltis has developed a regional CalVal technique, which aims at increasing the number and the repeatability of the altimeter bias assessments by determining the altimeter bias both on overflying passes and on satellite passes located far away from the calibration site. In principle this extends the single site approach to a wider regional scale, thus reinforcing the link between the local and the global CalVal analyses.
The regional method was initially developed at the Corsican calibration sites of Senetosa and Ajaccio. It was then successfully implemented at the Californian site of Harvest and at the Australian site of Bass Strait, in close collaboration with JPL and the University of Tasmania, respectively. The method was used to compute the altimeter biases of Jason-1, Jason-2, Envisat and SARAL/AltiKa at all these sites, which provided the first Envisat and SARAL/AltiKa absolute bias estimates at non-dedicated sites using the same method. These various studies demonstrated the high consistency of the regional approach with the analyses of the global CalVal teams and the work of the local in situ CalVal teams.
The method has been used in the frame of the ESA MPC-S3 project to monitor the Sentinel-3 mission at the three calibration sites (Corsica, Harvest and Bass Strait). We present the results obtained for the Sentinel-3A and Sentinel-3B satellites, the regional CalVal approach being of particular interest for the latter, as it does not pass close to any of the considered calibration sites and classical direct comparisons with the in-situ data cannot be performed. In general, the regional technique shows high potential for the monitoring of any altimetry missions.
However, Noveltis has developed a regional CalVal technique, which aims at increasing the number and the repeatability of the altimeter bias assessments by determining the altimeter bias both on overflying passes and on satellite passes located far away from the calibration site. In principle this extends the single site approach to a wider regional scale, thus reinforcing the link between the local and the global CalVal analyses.
The regional method was initially developed at the Corsican calibration sites of Senetosa and Ajaccio. It was then successfully implemented at the Californian site of Harvest and at the Australian site of Bass Strait, in close collaboration with JPL and the University of Tasmania, respectively. The method was used to compute the altimeter biases of Jason-1, Jason-2, Envisat and SARAL/AltiKa at all these sites, which provided the first Envisat and SARAL/AltiKa absolute bias estimates at non-dedicated sites using the same method. These various studies demonstrated the high consistency of the regional approach with the analyses of the global CalVal teams and the work of the local in situ CalVal teams.
The method has been used in the frame of the ESA MPC-S3 project to monitor the Sentinel-3 mission at the three calibration sites (Corsica, Harvest and Bass Strait). We present the results obtained for the Sentinel-3A and Sentinel-3B satellites, the regional CalVal approach being of particular interest for the latter, as it does not pass close to any of the considered calibration sites and classical direct comparisons with the in-situ data cannot be performed. In general, the regional technique shows high potential for the monitoring of any altimetry missions.