WEDDELL SEA SHELF WATER IN THE BRANSFIELD STRAIT AND WEDDELL-SCOTIA CONFLUENCE

The unusual stratification of the waters in the Weddell-Scotia Conflue nce between the Scotia and Weddell Seas and in the Bransfield Strait i s traced to the influence of shelf waters from the northwest Weddell S ea. The shelf waters span the density range encompassed by the warm, s alty Circumpolar Deep Water (CDW) of the Antarctic Circumpolar Current , and the colder and slightly fresher CDW in the Weddell Sea. An isopy cnal mixture of these three source waters flows eastward from the tip of the Antarctic Peninsula into the Weddell-Scotia Confluence region, and westward north of the Peninsula, where it flows downslope to renew the deep waters of the Bransfield Strait. This mixing scheme can occu r year-round, in contrast to some previous explanations of the stratif ication in the region, which relied on the (unobserved) winter convect ive overturn of the water column.