Circulation on the western South Atlantic continental shelf: 2. Spring and autumn realistic simulations

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Buoyancy‐driven currents are here investigated in a complex scenario, where two river plumes (the La Plata River and the Patos Lagoon plumes) occur in the vicinity of two opposing western boundary currents (the Malvinas and the Brazil currents). The study addresses the contrasting scenarios found during the austral spring and fall seasons, due to variations in river discharge, in wind stress, and in the boundary current transport. The winds blow preferably from the northeast during the spring and from the southwest during the fall. The Brazil Current transport is stronger during the spring, when the Brazil‐Malvinas Confluence is displaced southward, and weaker during the fall when the confluence moves northward. The study is conducted as a series of numerical simulations which consider the river discharges, the tides, variable wind stress, and thermohaline fields which are realistic in terms of the Brazil‐Malvinas Confluence. Our discussion focuses on the riverine water distribution in each season. The austral fall scenario shows coastally trapped plumes, and the spring scenario shows significant offshore removal, but our fall plumes are not too elongated and narrow as other authors found in the presence of constant winds, no tides, and no boundary currents, and our spring offshore removal is not as strong as found by others.