IADO   05364
INSTITUTO ARGENTINO DE OCEANOGRAFIA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Dynamical Balance of the Magellan Plume
Autor/es:
ELBIO D. PALMA; RICARDO P. MATANO; LINA SITZ; ALBERTO R. PIOLA
Lugar:
Bahia Blanca, Argentina
Reunión:
Conferencia; Science and management of estuaries and coasts (ECSA44); 2008
Institución organizadora:
Estuarine and Coastal Sciences Association
Resumen:
Low salinity plumes have a strong impact on the biology of coastal waters throughenhancement of the stability of the water column, entrainment of nutrient rich-water andredistribution of sediments, nutrients and larvae. In this study we examine the physicalprocesses that control the formation and evolution of the low salinity Magellan Plume,that covers large part of the Patagonian Shelf using a three dimensional numericalmodel. The model is forced by five tidal constituents, annual mean low salinitydischarges and climatological satellite-derived winds (QuikScat). The low salinityinflow, combined with the local forcing produces a low salinity tongue that extendsnortheastward from 52º30´S to about 39ºS, but the spatial structure of the buoyancycurrents are significantly modified by the tides. As a result, the plume presents anoffshore displacement close to 52ºS and creates a relatively sharp salinity contrast withambient shelf waters. The physical mechanisms that support the salinity front areanalyzed by means of momentum balances computed from four different numericalexperiments. Our analysis suggests that the modification of the cross-shelf barotropicpressure gradient produced by the interaction of the low salinity discharge fromMagellan Strait and the vigorous tidal mixing present in Grande Bay is in large partresponsible for setting up the intense cross-shelf salinity gradient and related northwardresidual flow that closely follows the 100 m isobath. The further addition ofclimatological winds moves the core of the northeastward jet inshore and slightlyincreases the frontal jet velocity. The cross-shelf surface salinity structure produced byour most realistic simulation is in very good agreement with in-situ observations.