ON THE INTERMEDIATE AND DEEP-WATER FLOWS IN THE SOUTH-ATLANTIC OCEAN

A multiparameter analysis is applied on zonal and meridional hydrograp hic sections obtained for the South Atlantic Ventilation Experiment (S AVE) to determine the spreading and mixing of water masses in the Sout h Atlantic Ocean, focusing our interest on the large-scale flow of int ermediate and deep waters. The method utilizes all information from th e hydrographic data set including temperature, salinity, dissolved oxy gen, and nutrient fields. Mixing proportions are quantified and plotte d along the eight sections considered. Results show no evidence of a p rimary route of Antarctic Intermediate Water along the western boundar y of the South Atlantic. In the eastern basin the eastward extension o f the Upper North Atlantic Deep Water (NADW) in the Guinea Basin follo wing the cyclonic subequatorial gyre is confirmed. In the Angola Basin a weak but thick NADW core layer is observed in conjunction with very little presence of Lower Circumpolar Deep Water (LCDW). High LCDW con centrations in Cape Basin are indicative of the communication of this basin to cold water sources in the south. The method is sensitive enou gh to detect for instance the presence of the Congo River Plume in the Angola Basin or the influence of the Weddell Sea Deep Water in the vi cinity of the Romanche and Chain Fracture Zones in the equatorial regi on. In conjunction with the multiparameter analyses along SAVE section s, an analysis of components of the residual vector R indicates a midd epth minimum in the R-N/P utilization ratio. Both a suitable explanati on for the minimum and the potential consequences for the multiparamet er analyses of South Atlantic water mass circulation are still to be f ound.