Circulação geostrófica e massas de água na baía de Bazaruto

Abstract

This work describes the pattern of Geostrophic Circulation and Water Masses in Bazaruto Bay, using “in situ” data of salinity, temperature, pressure and density, collected by CTD in an oceanographic cruise, carried out on January 3rd and 5th, 2005. Ocean circulation was estimated using the simplified hydrodynamic method of geostrophic balance, which depends on the knowledge of horizontal density variation. The water masses were determined from the T-S diagram and the analysis of the vertical profiles of temperature and salinity. The circulation pattern inside Bazaruto Bay is characterized by an hourly circulation, determined by density, and an inverse estuarine circulation due to excess evaporation in relation to precipitation and little freshwater drainage into the bay. of less salinity that enters the bay through the “mouth” flows, superficially, moving on the east side, while the more saline water leaves the bay on the west side and is sub-superficial. Bazaruto Bay has two water bodies: (1) ocean water body, on the north and east side, with relatively low salinity and temperature; (2) coastal water mass on the south and west side characterized by relatively high salinity and temperature. The salinity value is highest at the bottom of the bay (South) and on the west side (37.5 PSU) and lowest at the mouth (North) and east side (35.2 PSU). The temperature is also higher at the bottom of the bay (South) and on the western side (31.5°C) and lower on the mouth (North) and on the eastern side (29°C). Bazaruto Bay a presents a horizontal gradient of the parameters under study and is vertically homogeneous, it can also be seen from the density that the water column is mixed, favoring productivity, which is why Bazaruto supports an important fishery.(TRADUÇÃO NOSSA)