Transport and structure within the Antarctic Circumpolar Current to the north of south Georgia

Abstract

The Antarctic Circumpolar Current (ACC) crosses rugged topography to the north of South Georgia. In this region the subsurface expression of the Polar Front (PF) is generally thought to occur north of the Maurice Ewing Bank (MEB) close to the Subantarctic Front (SAF). However, in January 1996 the PF was south of the bank, separate from the SAF, in a position where it was most likely constrained by local bathymetry. High rates of transport (25 Sv eastward) were present at the PF, consistent with previous estimates for this current core. High transport rates (20 Sv westward) were also present along the northern shelf of South Georgia close to where the southern ACC Front (sACCF) has previously been reported. During our occupation, the sACCF was not encountered as it probably lay outside the survey area. Comparisons with recent circumpolar analyses emphasise the potential for variability in the region.