Variability of the meridional overturning circulation and the heat and salt transport in the South Atlantic: interpretation and validation of numerical simulations

Abstract

Variations in the South Atlantic Meridional Overtuning Circulation (AMOC) are strongly linked to important climatic changes. Current knowledge about the AMOC and its mechanisms has been largely described by numerical models. Although less efficient to investigate features as the AMOC, observational data are essential to evaluate the performance of numerical models. Up to date, the greater part of the observations of the MOC have been concentrated in the North Atlantic though some studies suggest the South Atlantic as key to its understanding. In the recent years, a concentrated international effort have been implemented in the South Atlantic, with the support of FAPESP (Thematic Project SAMOC, Proc. 2011/50552-4). The South Atlantic is the unique ocean basin to have a meridional heat transport toward the equator and to export part of this heat to the northern hemisphere. This heat transport to the northern hemisphere depends on the mixing between the cold and low salinity waters coming from the Pacific, through the Drake Passage, and the relatively warmer and saline waters coming from the Indian Ocean, the Agulhas leakage. The work here proposed will be performed at RSMAS from University of Miami in the context of the postdoctoral project, Proc. 2011/23931-4, and the Project SAMOC and will focus in the evaluation of the impacts of changes in the Agulhas leakage on the circulation and heat and salt transport in the South Atlantic. (AU)