Mechanisms maintaining southern ocean meridional heat transport under projected wind forcing

Abstract

Meridional heat transport (MHT) in the Southern Ocean (SO) and its components are analyzed with two eddy-permittingclimate models. The two models present a consistent picture of the MHT response to projected twenty-first-century changes in SO winds. In agreement with a recent analysis based on an ocean data synthesis product, much of the MHT in the SO is found to be due to the time-mean fields of meridional velocity and temperature. The change in the net MHT tends to besmall relative to the interannual variability at most SO latitudes. However, both models exhibit significant changes at most latitudes south of 308S in individual components of MHT. A simple framework wherein changes in the eddy and mean heat transports tend to compensate each other is not supported by the authors' results. Instead, the MHT response is composed of sizeable contributions from essentially all of the MHT components, with the eddy and mean heat transports often having the same sign. © 2012 American Meteorological Society.