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The CASSIS project is a French-Argentine cooperation tostudy the circulation in the Southwestern Atlantic fromin situ and satellite altimetry data. Seven moorings thatmeasure currents, temperature, conductivity andpressure and a fully equipped oceanographic buoycollected in situ data between December 2014 and May2017. During the first year (December 2014-November2015) the moorings were deployed below Jason-2satellite altimeter track #26, covering the northernportion of the Malvinas Current (MC) and Patagoniancontinental shelf (PCS). In December 2015 theinstruments were recovered and redeployed for a yearand a half along a zonal section at 44.7ºS. A summary ofthe results obtained are reviewed here and incomplementary presentations in this meeting (Artana etal, Lago et al, Paniagua et al, Ferrari et al). In-situ surfacecurrents and geostrophic velocities obtained fromsatellite altimetry are significantly correlated at theshelf-break (0.7). In the continental shelf correlation islow and significant (0.3) only when the Ekmancomponent is added to the satellite-derived velocity.During specific events associated with the presence ofmesoscale eddies at the shelf-break and to the passageof synoptic storms at the continental shelf, differencesbetween remote and in-situ currents are larger.During the period of measurement, the MC at 41ºS canbe characterized by two distinct regimes where alongslopevelocities are either (i) large, surface-intensified or(ii) weak with almost zero vertical shear. The weakregime is due to an upstream retroflection of theMalvinas Current to the east. A large shift of thestructure of the water masses accompany the alongslopevelocity change: all water masses deepen and shifteastward during the weak regime. Thus, measurementsshow that the vertical structure of the water column is acritical information that is needed in the attempt to usesatellite altimetry as a proxy of subsurface currents.