On the Circulation of the South Atlantic Ocean

Abstract

In a recent study (Reid, 1994) maps of the general circulation of the Atlantic Ocean were presented and discussed. The emphasis was placed upon the exchange of waters between the North and South Atlantic as indicated by the patterns of characteristics.

The exchange with the waters entering through the Drake Passage involves further discussion of the effect of the Atlantic waters in providing a major defining characteristic of the Circumpolar Water — the layer of warm and saline water. The associated features — the high oxygen and low nutrient concentrations - are also defined well for a long distance down stream in the Antarctic Circumpolar Current. However it is only the vertical maximum in salinity that persists all along the flow around Antarctica and through the Drake Passage into the South Atlantic.

This returning salinity maximum is much lower than the salinity maximum from the north that it meets and mixes with in the South Atlantic. Part of their mixture turns back northward into the South Atlantic where it appears as the vertical maximum in salinity seen in the east, but lower in salinity than the maximum seen along the western boundary. The rest of the mixture continues eastward, with its salinity increased well above that of the Drake Passage water and begins another circuit of Antarctica.