Mariano Tonini (IPATEC-CONICET-UNCO, Argentina); Martin Saraceno (CIMA/CONICET-UBA, Argentina)

The San Matías Gulf (GSM) is a semi-closed basin of about 150 km in meridional extension and 100 km in zonal extension, the largest of the so-called north Patagonian gulfs in Argentina, centered at 41° 30' S. Here, we studied the climatological oceanic flow of heat and salt through the mouth of the GSM with the use of a high-resolution baroclinic regional numerical model (CROCO). Because of an excess of evaporation over precipitation all year-round and maximum solar radiation during summer, fresh and cold shelf water that enters the gulf in summer by its south edge of the mouse keeps recirculating in a cyclonic gyre to be advected along the north end of the gulf during autumn with a higher content of salt and heat. We also correlate the surface velocities from our model with those infer from satellite altimetry and with current meters arranged in four moorings along the gulf mouth. The barotropic structure found in the zonal currents that feed the gulf its a key feature to build, with the help of altimetry data and other satellite measures, a long term time series of oceanic heat and salt flux across the gulf mouth. The circulation system, as well as the heat and salt fluxes that exchange the gulf with the continental shelf, have a significant ecological impact, including local fisheries, and therefore influence the well-being of the population that depends directly or indirectly on said ecosystems. The modelling and in situ mooring efforts are part of the SABIO EUMSTAT-CNES project.