Seawater temperature changes associated with the North Brazil current dynamics

Abstract

This study used hydrographic data (CTD and ADCP) collected along the north Brazilian continental shelf and the adjacent oceanic area (the north Brazilian zone) and 13 years of monthly data of sea surface temperatures (SSTs) obtained from the Tropical Rainfall Measuring Mission satellite microwave images. In July and August 2001, the core of the North Brazil Current (NBC) with a velocity exceeding 1.2 m s−1 in the upper 150 m was observed near the break of the north Brazilian continental shelf. The satellite and in situ SSTs from the same time indicate that relatively cold waters (<27.5 °C) extended throughout the NBC region where the vertical distribution of temperature displayed a rise of the 26 °C isotherm to near the surface on transects where the NBC was more intense. These observations indicated that the NBC plays an important role in temperature changes in the water column near and/or over the north Brazilian continental shelf margin even at times when, theoretically, the NBC may be expected to be less intense (April–May) and warm waters dominate the area. The distribution of accumulated temperature change reveals that the NBC may contribute to possible nutrient upwelling of the bottom boundary layer along the continental shelf to surficial areas and offshore following the NBC deflection or merely into the North Atlantic.