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Instability processes in Deep Western Boundary Current along the Pernambuco plateau

Grant number: 18/06153-7
Support type:Scholarships in Brazil - Scientific Initiation
Effective date (Start): June 01, 2018
Effective date (End): December 01, 2019
Field of knowledge:Physical Sciences and Mathematics - Oceanography
Principal Investigator:Ilson Carlos Almeida da SIlveira
Grantee:Felipe Vilela da Silva
Home Institution: Instituto Oceanográfico (IO). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The climate of Earth has a broad influence of MOC (Meridional Overturning Circulation). The Deep Western Boundary Current (DWBC) is responsible to transport North Atlantic Deep Water (NADW) interhemispherically. The DWBC flows adjacent to the american continental margin and has been considerably studied between the South of Labrador Sea (48ºN) and about 35ºS, around the Eastern Brazilian coast. Nevertheless, when the current hits the latitudinal range between 5ºS and 11ºS, the DWBC instabilizes and breaks into anticyclonic vortices and migrate Southward.This proposal intends to describe and characterize the local and the kinematics and dynamics properties of DWBC around the destabilization site. The development of this study will apply the Classic Dynamics Method for hydrographic data from the commission of the Brazilian Navy: Northeast Ocean I and II. Vertical and horizontal standards of circulation will be described for a big range of depth averaged for the three isopycnal layers wich are used to tell NADW layers. In order to reduce the background noise in Brunt-Väisällä frequency calculation, it's suggested to estimate the Ertel's potential vorticity in this three layers. The overlay of the stream function field and the potential vorticity will allow the inference of the development and flow and identification of propagation as much as the instability of DWBC and its vortices.