info:eu-repo/semantics/article
Circulation and Hydrography in the western South Atlantic shelf and export to the deep adjacent ocean - 30 to 40S
Fecha
2020-10Registro en:
Berden, Giuliana; Charo, Marcela; Moller Jr., Osmar O.; Piola, Alberto Ricardo; Circulation and Hydrography in the western South Atlantic shelf and export to the deep adjacent ocean - 30 to 40S; Wiley Blackwell Publishing, Inc; Journal of Geophysical Research; 125; 10; 10-2020; 1-18
0148-0227
2169-9291
CONICET Digital
CONICET
Autor
Berden, Giuliana
Charo, Marcela
Moller Jr., Osmar O.
Piola, Alberto Ricardo
Resumen
High sea surface chlorophyll concentration on the Argentine Continental Shelf frequently extends to the deep ocean in the vicinity of the Brazil/Malvinas Confluence (BMC). The offshore transport of shelf waters likely plays a key role in the biogeochemical balance of the western South Atlantic and promotes the offshore transport of planktonic species. We analyze data from an oceanographic survey carried out in the western South Atlantic shelf between 31°S and 38°S in October 2013. We describe the distribution and circulation of the water masses and focus on the exchanges with the open ocean. On-shelf subsurface intrusions of oceanic waters and river discharge supply nutrients to the shelf. A low-salinity tongue of Río de la Plata (RDP) waters extends northward to 32°S. Below these waters Subantarctic and Subtropical Shelf Waters (SASW and STSW) meet to form the Subtropical Shelf Front. The main SASW branch, oversaturated in oxygen and with high-fluorescence mixes with a detachment of Brazil Current waters at 38°S and is exported offshore along the BMC. A second branch of SASW reaches 33°S mixing along its way with RDP and STSW and returns southward after splitting into an onshore and an offshore branch. The offshore branch is exported to the open ocean through the BMC. These export routes are in overall qualitative agreement with those indicated by a high-resolution reanalysis. We estimate a net off-shelf transport (geostrophic [96.2%] plus Ekman [3.8%]) of 3.44 Sv to the open ocean between 32.1°S and 37.7°S. The majority of the offshore flow occurs between 34.7°S and 37.7°S.