CoAuthors

Matthias Raynal (CLS, France); Marion Orsztynowicz (CLS, France); Stéphanie Urien (CLS, France); Sylvain Jourdain (CLS, France); Laiba Amarouche (CLS, France); Pierre Féménias (ESA, Italy); Jérôme Benveniste (ESA, Italy); François Boy (CNES, France); Salvatore Dinardo (EUMETSAT, Germany)

Sentinel-3A mission was successfully launched in February 2016. It is a multi-instrument mission to measure sea-surface topography, sea- and land-surface temperature, ocean colour and land colour with high-end accuracy and reliability. We focus here on the observations acquired by the sea-surface topography payload that encompasses a dual frequency altimeter, a dual frequency radiometer and Doris and GNSS sensors. A specificity of the Sentinel-3A mission is that it embarks a Delay Doppler altimeter. The SRAL altimeter operates continuously in Delay Doppler mode (or the so-called SARM) over all surfaces since the 12 April 2016.

We will present the performance of the SARM observations over ocean through the assessment of the Sentinel-3A Level 2 products. The SARM processing within the Sentinel-3A operational ground segment is quite close to other existing ones (CNES processing and GPOD processing for instance) either for the Doppler processing or for the retracker. Different metrics will show the performance of the SARM sea level, wind and wave data by:
• comparing with other altimetry missions
• comparing with PLRM mode which is an LRM like processing that allows detecting very small residual errors on the SARM data
• comparing with other Delay Doppler processing such as the CNES processing already assessed over Cryosat time series and now on Sentinel-3A mission