Oceanic Fluxes in the South Atlantic

Abstract

A box inverse of the World Ocean Circulation Experiment A10 (30°S) and A11 (nominally 45°S) sections in the South Atlantic Ocean was undertaken. The authors find a heat flux across A10 of 0.22 ± 0.08 PW, consistent with previous studies, and a heat flux of 0.43 ± 0.08 PW across A11. The A11 heat flux is lower than some previous analyses of this section but implies a plausible oceanic heat convergence (heat loss to the atmosphere) of 0.21 ± 0.10 PW. The difference is principally due to adding a cyclonic component to the circulation in the Cape Basin. As compared with the solution of other studies, the anticyclonic circulation in the surface and intermediate water of the subtropical gyre is weakened. The circulation of the deep water is cyclonic rather than anticyclonic; this is in better agreement with previously published circulation schemes based on examination of water properties. A southward freshwater flux of 0.7 Sv (1 Sv ≡ 106 m3 s?1) at A11, consistent with previous inverse studies, is still inconsistent with the net Atlantic evaporation inferred from integrated surface climatologies. Results suggest a small gain of freshwater (0.2 ± 0.1 Sv) between the sections.