Abstract's details
First analysis of the Sentinel-3 SRAL data over inland water
CoAuthors
Event: 2016 SAR Altimetry Workshop
Session: SAR mode performances: SAR CALVAL from Cryosat-2 and Sentinel-3
Presentation type: Type Poster
Contribution: not provided
Abstract:
The Sentinel-3 Mission (S-3), launched in December 2015, is part of the Global Monitoring for Environment and Security (GMES/Copernicus) European initiative. For oceanic applications, the S-3 mission delivers continuity to existing ESA ERS, Envisat and CryoSat-2 missions. The topography payload consists in a Delay Doppler altimeter (SRAL), a microwave radiometer MWR and 3 instruments for precise orbit computation purposes (GNSS, DORIS and laser reflector). The Sentinel-3 satellite flies on a new orbit with a 27-days cycle.
The SRAL instrument is a nadir Ku/C altimeter, with two operating modes: the low resolution mode (LRM), used for all past oceanographic missions and the high resolution mode (SAR) used for the first time on CryoSat-2. The LRM mode has been activated during one cycle at the beginning of the S-3 mission while the SAR mode is activated since then. The SAR mode (also called Delay Doppler mode) provides an improved along track resolution (around 320m) with respect to the LRM mode. During the commissioning phase (S3E1 phase), CNES has been in charge of the topography calibration and validation in support to ESTEC teams and with the support of CLS team.
In this paper, we will present a first data quality assessment focussed on inland water regions. This includes analyses of the coverage of the main inland water bodies, of the waveform centering for different tracking modes and of the evolution of the various parameters during the water surface overflight (waveforms, range integrated power, water level, etc..). The impact of the Level-1 processing on these parameters will be addressed.
The analysis will be based on S-3 data processed by the CNES prototype chains (Sentinel-3 Processing Prototype) as well as on S-3 ESA land products. The S3PP has been used to implement and test new algorithms and methods that would permit to better estimate water heights. In this study the importance to use innovative algorithms dedicated to hydrological zones have been clearly demonstrated. The results will be compared to products of other missions such as Jason-2/3 or SARAL/AltiKa focusing on the SAR mode added value for improving the observation of inland water bodies.
The SRAL instrument is a nadir Ku/C altimeter, with two operating modes: the low resolution mode (LRM), used for all past oceanographic missions and the high resolution mode (SAR) used for the first time on CryoSat-2. The LRM mode has been activated during one cycle at the beginning of the S-3 mission while the SAR mode is activated since then. The SAR mode (also called Delay Doppler mode) provides an improved along track resolution (around 320m) with respect to the LRM mode. During the commissioning phase (S3E1 phase), CNES has been in charge of the topography calibration and validation in support to ESTEC teams and with the support of CLS team.
In this paper, we will present a first data quality assessment focussed on inland water regions. This includes analyses of the coverage of the main inland water bodies, of the waveform centering for different tracking modes and of the evolution of the various parameters during the water surface overflight (waveforms, range integrated power, water level, etc..). The impact of the Level-1 processing on these parameters will be addressed.
The analysis will be based on S-3 data processed by the CNES prototype chains (Sentinel-3 Processing Prototype) as well as on S-3 ESA land products. The S3PP has been used to implement and test new algorithms and methods that would permit to better estimate water heights. In this study the importance to use innovative algorithms dedicated to hydrological zones have been clearly demonstrated. The results will be compared to products of other missions such as Jason-2/3 or SARAL/AltiKa focusing on the SAR mode added value for improving the observation of inland water bodies.