Water types and volumetric considerations of the South-East Atlantic upwelling regime

Abstract

A preliminary investigation was carried out to establish the characteristic temperature-salinity (t/s) relationships of the upwelling, mixing and pure oceanic domains of the South-East Atlantic Ocean. The upwelling and oceanic regimes have disparate and non-overlapping t/s characteristics, whereas the mixing regime shows characteristics of both the other regimes. Upwelled water is derived from South Atlantic Central Water, which is heated at the sea surface to a maximum of 23°C. A volumetric analysis for the same geographic area shows that, for the area as a whole, South Atlantic Subtropical Surface Water is dominant at the sea surface and that, furthermore, the volumes of Central Water available for upwelling are invariant with bivariate t/s class. This suggests that the origin of upwelled water, and the intensity of upwelling, may be estimated from salinity readings only.