Water Mass Distribution on the Shelf and Shelf-Break Upwelling in the Southeast Brazil Bight
NAVAL RESEARCH LAB STENNIS SPACE CENTER MS MESO- AND FINESCALE OCEAN PHYSICS SECTION
Pagination or Media Count:
The region along the Brazilian coast situated between 22 deg S and 28 deg S is usually referred in the literature as the Southeast Brazil Bight SBB. In the central part of the SBB 23 deg - 26 deg S, the continental shelf is relatively wide, with width reaching over 240 km in the region offshore of Santos. On the shelf, both the dynamics and the water mass structure are strongly influenced by intrustions of the BC, caused by the frequent meandering of that western boundary current. During the austral Summer, mostly due to the prevailing northeasterly winds, the water column is usually well stratified. The occurrence of intense coastal upwelling is frequently observed, especially in the region around Cabo Frio 22 deg S, and IIha de Sao Sebastiao 24 deg. Campos et al., suggested that the combination of this wind driven upwelling induced by BC cyclonic meanders constitute a mechanism responsible for pumping up oxygen and nutrient-rich SACW to the euphotic zones in the inner parts of the continental shelf. Incidentally, these shallower regions between 23 deg and 27 deg S are the most important spawning regions for the Brazilian Sardine Sardinella Aurita. In this paper we discuss the water mass characteristics of the SBB continental shelf, based on AVHRR and hydrographic data collected during quasi-synoptic hydrographic cruises in the SBB during the Summer and Winter of 1993, and the Summer of 1994. The data set is described in Section 2. In Section 3 we discuss the surface temperature and salinity distributions. The three-dimensional water mass structure and time-variability are discussed in Section 4. In Section 5 we discuss the results and draw some conclusions.
- Biological Oceanography
- Physical and Dynamic Oceanography