Numerical diagnostic of the circulation in the Santos Bight with COROAS hydrographic data

Abstract

This work represents part of the analyses of the data generated during the first two mesoscale hydrographic cruises of COROAS Project: one during the Summer and the other during the Winter of 1993. The area surveyed during these cruises is the region of the South Brazil Bight (or Santos Bight) limited at the coast by the cities of Ubatuba and Iguape, extending from the 50 m isobath to oceanic regions with depths greater than 2500 m. The main goal of this work consisted of the adaptation of the Princeton Ocean Model to the area of study, including realistic topography, observed thermohaline structure and open boundaries. Using this model, a set of diagnostic experiments was realized using density structures based on the COROAS hydrographic data. The baroclinic velocity fields obtained, as expected from preliminary analyses of the thermohaline structures, showed similar features for the Brazil Current in bOla seasonal cruises. The results show an intrusion of Tropical Water over the continental shelf in the region between Ubatuba and Santos, both during the Summer and the Winter cruises. The results also suggest the penetration of the South Atlantic Central Water, underneath the Tropical Water, to the external part of the continental shelf in both occasions.