Estimation of the Transport of Heat in the Southern Ocean Using a Fine-Resolution Numerical Model

Abstract

Results from a numerical model of the Southern Ocean (the U.K. Fine-Resolution Antarctic Model) have been used to repeat the calculations of De Szoeke and Levine, who used hydrographic data to estimate the advective heat transport across a circumpolar path of constant vertically averaged temperature. The results from the model suggest that the mean flow is responsible for only a small proportion of the heat transport and that the main process carrying heat poleward across such a path is indeed eddy heat transport. A comparison is made with the heat transport across constant latitude circles. Although the mean flow (consisting of large-scale meanderings of the Antarctic Circumpolar Current across the latitude circle) plays a more important role in this case, there is good correspondence between total heat transports across contours of constant vertically averaged temperature and those across constant latitude circles. Diffusive fluxes, in part representing subgrid-scale processes, also play an important role in the model with such fluxes complementing the advective eddy heat transport.