Structure and Transport of the Antarctic Circumpolar Current at Drake Passage from Short-Term Measurements

Abstract

Three-week average speeds from an array of current meter moorings which spanned Drake Passage were used in conjunction with geostrophic calculations to estimate the short-term transport of the Antarctic Circumpolar Current. Closely spaced hydrographic stations show that the current consists of three vertically coherent bands of relatively high speed within the generally eastware flow. These bands separate four water mass regimes which have distinct T- S relationships at depths above the core of the Circumpolar Deep Water. The geostrophic transport relative to 300 db averaged 95times10 6 m 3 s -1 for five transects of the Passage and is consistent with previous measurements. Referencing the geostrophic transport to the current meter measurements gives an adjusted transport of 124times10 6 m 3 s -1 to the east.