Physical oceanography during WEPOLEX-81

The physical oceanographic objective of the U.S.-U.S.S.R. Weddell Polynya expedition (WEPOLEX-81) was to resolve the vertical and horizontal scales of the thermohaline stratification of the water column below the sea ice and, if possible, within the Weddell polynya. The low vertical stability of the southern ocean water column permits significant vertical fluxes of heat and salt (Gordon 1981). These fluxes strongly influence the sea ice budget and water mass conversion, and they are believed to be particularly active in the winter. Water mass conversion during the Weddell polynya period 1974-76 was significant. The thermal structure and surface parameter traces along the return track from 61 degree S to 53 degree S reveal the varied stratification and surface water conditions across the transition from the ice interior to the open ocean. The transition region, or ice edge zone, is associated with increased vertical relief of isotherms and variation in the surface nutrients.