The Salinity Signature of the Cross-Shelf Exchanges in the Southwestern Atlantic Ocean: Satellite Observations
[13-Nov-2014] Guerrero, R., Piola, A., Fenco, H., Matano, R., Combes, V., Chao, Y., James, C., Palma, E., Saraceno, M., and Strub, T.
Presented at the 2014 Aquarius/SAC-D Science Team Meeting
We use sea surface salinity (SSS) data from Aquarius and SMOS to describe the shelf-open ocean exchanges in the western South Atlantic near 35°S. The satellite data show a well-defined seasonal pattern. During spring and summer low SSS shelf waters expand offshore and are transferred to the open ocean primarily southeast of the river mouth (from 36 °S to 37°30'S). During fall and winter low SSS waters extend along a coastal plume and the export path to the open ocean distributes along the offshore edge of the plume. The seasonal SSS variations over the shelf are modulated by the along-shelf component of the wind stress over the shelf. However, the combined analysis of SSS, satellite-derived sea surface elevation and surface velocity data suggest that the precise location of the export of shelf waters depends on offshore circulation patterns, such as the location of the Brazil Malvinas Confluence and mesoscale eddies and meanders of the Brazil Current. The satellite data indicate that in summer, mixtures of low salinity shelf waters are swiftly driven towards the ocean interior along the axis of the Brazil/Malvinas Confluence. In winter, episodic wind reversals force the low salinity coastal plume offshore where they mix with tropical waters within the Brazil Current and create a warmer variety of low salinity waters in the open ocean.