Global and Regional Evaluation of the First Year of Sentinel-3: Possibilities and Challenges for MSS Determination

The new Synthetic Aperture Radar (SAR) data from the Sentinel-3 satellites will provide the community with valuable new information in coastal areas and in the Arctic, due to the higher along-track resolution obtained through the Delay-Doppler processing. The SAR data also allows for a more detailed study of the ocean surface, since these make small-scale variations visible. Combined, data from the Sentinel-3 satellites creates a tremendous possibility for improving tidal models and mean sea surfaces near the coast, where these models are currently using extrapolation to provide information. However, some challenges are also becoming more apparent in areas where satellite altimetry have not previously been available. Such as the discrepancies between tidal models near the coast, which are amplified because the Sentinel-3 satellites fly in a sun-synchronous orbit. Acquiring satellite altimetry data in coastal and sea ice covered areas also highlights some issues with the current wet tropospheric correction, calculated from measurements by the on-board microwave radiometer, leading us to the conclusion that it is safest to use a WTC from a model – at least in coastal and sea ice prone areas.