Results are presented for the atmospheric response in a coupled mixed layer ocean-atmosphere model of the southern hemisphere. The model is integrated for a period of 72 days for fixed January radiation conditions. the main feature of the model is a warming trend which occurs throughout the period in both the ocean and the atmosphere. This is shown to be due to the excess solar radiation at all latitudes, which causes an increase in sea surface temperature (SST), with the maximum increase of 3 ¿K occurring between 30 ¿S and 40 ¿S. As a consequence, the evaporation is increased in middle latitudes, and the resultant increased water vapor is transported to the equatorial region and higher latitudes, where condensation causes a warming of the troposphere. It is further shown that changes in the meridional temperature gradient occur which result in a poleward movement of the jet stream. These features of the model are shown to be similar to the observed seasonal change during the southern hemisphere summer, particularly in middle latitudes. An unexpected feature of the model is that the changes in atmospheric circulation result in changes in surface heat fluxes and wind stress which produce a further increase in hemispheric SST. The implications of this positive feedback mechanism on the development of SST anomalies are briefly discussed.