SMOS satellite monitors Sea Surface Salinity for more than 15 years

Le résumé fourni par la source

The monitoring of Sea Surface Salinity (SSS) over the Earth has been profoundly enhanced during the last fifteen years due to a new generation of satellite sensors. L-band radiometry is currently the only technology to measure SSS from space. The European Soil Moisture and Ocean Salinity (SMOS) mission was the first satellite mission to carry an L-Band radiometer. It has been launched in November 2009 and it is still in operation. Moreover, SMOS SSS observations have a spatial resolution of ~45km, made possible by the innovative Synthetic Aperture Radiometry technology used for the first time in Earth observation.This presentation will review some of the main achievements enabled by the 15 years of SMOS SSS observations.Ocean surface water masses are primarily defined by their temperature and salinity, building the Sea Surface Density, and featuring the ocean with fronts and jets, eddies and filaments. These oceanic features have a subsequent impact on water mass transformation, subduction and mixing, and ocean–atmosphere interaction. At high latitudes, in cold polar surface waters, a change of 0.1g/kg in SSS, is equivalent, in terms of density, to a change of 1°C in sea surface temperature. This is the reason why salinity play a key role in controlling the global thermohaline circulation.The SMOS SSS time series enabled to document with an unprecedent synoptic coverage SSS interannual variations at planetary scale related to climatic events such as El Niño Southern Oscillation or Indian Ocean Dipole. Moreover, it revealed large mesoscale structures related to river discharges interacting with ocean eddying circulation and biological features, as well as feedbacks on atmospheric processes such as the reinforcement of strong tropical cyclones overpassing fresh salinity cells. At high latitudes, SSS changes related to water cycle and ocean circulation changes are starting to be detected.These results open needs and perspectives for a SMOS High Resolution mission.

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