Limits: no east-west boundary, definition of northern boundary of the southern ocean is controversial, international hydrographic organization, in 2000, defined it from. Antarctic coast to 60 s: from an oceanographic point of view: south of a line where the tropical/temperate dynamics break down where the permanent thermocline reaches the surface subtropical front (stf) Bottom topography and geography: since acc reaches great depths, topography of the ocean floor has a large impact on circulation, combined effect of drake passage and the scotia ridge on the. Circumpolar current is quite dramatic: the current accelerates to squeeze through the gap and hits the obstacle at increased speed. It emerges highly turbulent and shifts sharply northward: the coastline of antarctica includes two major indentations: the. Weddell and ross seas: these do have western boundaries and thus support regional wind driven gyres with western boundary currents. Winds and currents: dominated by, westerlies from west in the latitude band 40-60 s drive the.