The Brazil current and intermediate Western Boundary Current flows through the Vitória-Trindade ridge

Abstract

In order to contribute to the description of the flows of the Brazil Current (BC) and the Intermediate Western Boundary Current (IWBC) through the submerged seamounts of the Vitória-Trindade Ridge (VTR), this work compiles data from three oceanographic commissions that took place in 2013 and 2014, between 19 e 23°S. One of the commissions was specially designed for the study of the flows in the main passages between the CVT seamounts, and the other two were systematic oceanographic surveys conducted by the Brazilian Navy in the region. The study analyzes a total of 83 oceanographic stations and vessel-mounted ADCP measurements. A combined analysis of remote sensing data was performed on mesoscale features that were sampled during the cruises. As the latitude increased, the BC was intensified. In the region of the seamounts, BC cores were observed between the Abrolhos Bank and the Besnard Bank, between the Besnard Bank and Vitória Seamount, and to the south of the Vitória Seamount. The zone between ~ 20 and ~ 21.5 ° S was characterized as a region where the BC flow got reorganized by the continental slope. To the south of 21,5 ° S, the flow presented high intensity. The IWBC was also intensified along its trajectory towards north. The flow was divided into three paths at the seamounts region. Through the channel between the Besnard Bank and Monte Vitória, the greater volume transport was observed. The importance of SACW and AAIW in the IWBC flow was comparable between 22 and 19 °S. At 19.5 ° S it was possible to verify that the IWBC was organized as a single and intense branch. Cyclonic and anti-cyclonic eddies, which were sampled during the cruises, reached depths greater than 500m, thus influencing the circulation of the BC and IWBC in the region.