THE INFLUENCE OF ANTARCTICA ON THE MOMENTUM BUDGET OF THE SOUTHERN EXTRATROPICS

The antarctic plateau acts as a strong heat sink for the global climat e, cooling the atmosphere and radiating energy to space. A cold dense atmospheric boundary layer is formed. Strong surface winds are formed as the boundary layer drains off the plateau. These drainage winds and the eddy fluxes necessary to maintain them are analysed in a ge neral circulation model (GCM). The drainage flow is well represented in the GCM. The associated mean meridional circulation is analysed in isentr opic coordinates. The momentum budget over Antarctica reveals a balanc e between the Eliassen-Palm flux convergence and the Coriolis torque e xerted by the mean meridional mass flux. Both vertical and horizontal components of the Eliassen-Palm flux contribute, the vertical componen t being the greater.