Oceanic Fluxes on the WOCE A11 Section

Abstract

Abstract The most southerly WOCE one-time section in the South Atlantic, designated A11, was occupied in January 1993. The cruise track lay across the cool subantarctic zone of the Circumpolar Current in the west and the warm subtropical gyre in the east. In this paper estimates of the flux of heat, salt, oxygen, and other tracers across the section are presented. A brief description of the distribution of physical and chemical properties is followed by a determination of the flux in the surface Ekman layer. Direct measurements of current shear made from a shipborne ADCP and estimates from cruise wind data and climatological data all yield a flux of 5 ± 1 Sv (Sv = 106 m3 s−1) equatorward. When combined with geostrophic estimates relative to a level near 3500 dbar, or the bottom where shallower, an initial guess for the flow field is derived. This initial guess is combined with absolute currents derived from the ADCP when the ship is underway. Unrealistic aspects of the circulation are found, and we conclu...