Two way interactions between the ocean mixed layer and the atmosphere control the position and strength of mean sea surface temperature (SST) gradients, both in the subtropics and midlatitudes. These interactions are studied in a global coupled Ocean - Atmosphere model, in an aquaplanet configuration. The ocean simply consists of a slab mixed layer forced by an interactive surface heat flux and a prescribed ocean heat transport convergence. It is coupled to a full atmospheric GCM, including a sophisticated parameterization of convection (Emmanuel and Zivkovich-Rotman, 1997) and high vertical resolution (40 levels).