Estimating Southern Ocean eddy flux of heat and salt from satellite altimetry

Abstract

An outstanding problem in the oceanic and atmospheric sciences is the rate of heat and fresh water transport from the equator to the poles, for it is this transport which powers the Earth's weather and climate system1. Closing the Southern Hemisphere balances has proven particularly difficult because of the dominance of eddy fluxes across the Antarctic Circumpolar Current (ACC). Their relatively small space, but long time scales, make any in situ measurement program prohibitively expensive. Here we use satel-lite data to estimate the overall eddy activity and a turbulence closure scheme to relate this to eddy flux. The resulting estimated heat flux is sufficient to supply the heat lost to the atmosphere south of the Antarctic Polar Front. Estimated salinity flux is found to be poleward at high latitude—in the wrong direction to com-pensate for the observed excess of precipitaton over evaporation south of the Polar Front.