What drives mid-latitudinal convection and the formation of Subantarctic Mode Water

Abstract

During the July WOCE Southern Ocean workshop in Hobart, the formation of Subantarctic Mode Water (SAMW) and Antarctic Intermediate Water (AAIW) was one of the many topics discussed in detail. One issue that was particularly emphasized, was the likely role of northward directed Ekman transport across the path of the Antarctic Circumpolar Current (ACC) and a possible contribution made by Antarctic-origin surface water to SAMW characteristics. Rintoul and Bullister (1997) reported some evidence of this contribution along the northsouth WOCE SR3 repeat section between Hobart and Antarctica. A northward directed Ekman transport of Antarctic-origin surface water is likely to explain the local freshening of the mixed layer observed north of the Subantarctic Front (SAF).