NOTES AND CORRESPONDENCE The Work Done by the Wind on the Oceanic General Circulation

A new estimate is made using altimeter data of the rate at which the wind works on the oceanic general circulation. The value of about 1 TW is lower than previously estimated and is dominated by the work done by the mean zonal wind in the Southern Ocean. The meridional component of the mean wind contributes primarily in the eastern upwelling regions of the ocean. Fluctuating component contributions are small. A comparison with the results of a numerical model produces both the same total work as well as the same general geographical patterns but with detailed differences. Both observations and model show that the subtropical gyres are regions where the atmosphere is braking the ocean circulation. The input of wind energy is shown to be qualitatively consistent with estimates of the rates of decay of barotropic and baroclinic mesoscale variability. If most of the energy input into the Southern Ocean is dissipated there, this region could be a dominant factor in mixing the global ocean.