Modeling the Offshore Export of Subantarctic Shelf Waters From the Patagonian Shelf

FRANCO, B. C.; PALMA, E. D.; COMBES, V.; ACHA, E. M.; SARACENO, M.

Journal of Geophysical Research: Oceans

American Geophysical Union

Año: 2018

It has been suggested that the Subtropical Shelf Front (STSF) could be a preferential site for thedetrainment of Subantarctic Shelf Water (SASW) and related planktonic shelf species onto the open SWAtlantic Ocean. The offshore detrainment of SASW and planktonic shelf species might be an exportationmechanism, affecting the population abundances of fishing resources in Argentina, Uruguay, and SouthernBrazil. In this study, we characterize for the first time the 3-D structure of the STSF and the main routes ofoffshore export of SASW from the Patagonian shelf during austral summer (summer and early fall) and winter(winter and early spring) by using numerical hydrodynamical model results and Lagrangian trackingsimulations of neutrally buoyant floats. The transport of SASWtoward the open ocean is ~1 Sv (1 Sv = 106m3/s)during summer and ~0.8 Sv during winter. SASW are exported offshore mainly near the Brazil-MalvinasConfluence region during both seasons. The STSF appears to act as an important retention mechanism for theplankton over the inner and middle shelf mainly during late summer and early fall. Our findings could explainthe life cycle of distinct fish species that are distributed in the region, as well as the population abundancevariability of such species.