Meetings: Documents

The Salinity Signal of the Shelf/Deep-Ocean Exchanges in the Southwestern Atlantic Region: Numerical Simulations
[13-Nov-13] Matano, R., Combes, V., Palma, E., Guerrero, R., Fenco, H., Strub, T., Piola, A.R., Chao, Y., and Saraceno, M.
Presented at the 2013 Aquarius/SAC-D Science Team Meeting
Observations and numerical simulations suggest that subantarctic and subtropical waters on the western South Atlantic continental shelf converge near 33°S. This convergence must be balanced by export of shelf waters to the deep oceans that, together with runoff from Río de la Plata (RdP) and the Patos Lagoon, create extensive regions of low salinity on the Brazil/Malvinas Confluence. In complimentary presentations we show that this shelf water outflow is a robust feature of satellite-derived temperature, salinity, surface circulation and numerical simulations (R. Guerrero and R. Matano). Hydrographic and current observations recently collected on the outer shelf and upper slope reveal that the complex offshore flux contains all the above mentioned varieties of shelf water. During this survey the RdP water and the warm-salty subtropical shelf water form relatively thin and narrow filaments near the shelf break. In contrast, the subantarctic shelf water occupies most of the water column. This suggests that subantarctic shelf waters are the main contributor to the low-salinity anomalies observed offshore. Further downstream the cores of shelf water masses are embedded and subduct within the swift Confluence circulation, except for mixtures of the buoyant RdP waters which remain at the surface.
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