In situ and satellite altimetry measurements to improve the knowledge of currents in the Patagonian Shelf and Slope
Séminaire de Martin Saraceno, Centro de Investigaciones del Mar y la Atmosfera (CIMA/CONICET-UBA) – Universidad de Buenos Aires (DCAO, FCEN-UBA) – Instituto Franco-Argentino para el Estudio del Clima y sus Impactos
Recent measurements of currents, temperature, salinity and pressure in the Patagonian shelf and adjacent slope are used together with satellite altimetry measurements to improve the knowledge of the region. We show that the Malvinas Current (MC) is affected by the passage of trapped waves along the slope and by the interaction with large eddies. Close to the confluence with the Brazil Current, the MC is dominated by the dynamics of the confluence that, at interannual scale, is driven by the propagation of planetary Rossby Waves. Over the Northern portion of the continental shelf, currents are mostly barotropic and largely dominated by the along-coast wind stress component through pressure gradient adjustment. This geostrophic adjustment holds from daily scales to interannual scales. The interannual variability is dominated by the Southern Annular Mode. Only very close (30 km) to the shelf break the MC affects the shelf currents. At seasonal scales, the fact that the MC transports always waters with very low temperatures, is responsible to create a thermosteric pressure gradient that modulates the currents in the Southern portion of the continental shelf close to the shelf break. Gridded satellite altimetry data compared very well with in situ data most of the time at most locations. The largest mismatch occurs when a poor along-track coverage is available to construct the gridded data.
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