Numerical Study of the impact of tropical heat sources during the austral summer

.A simple tridimensional meteorological model is used to study the effect of mid-tropospheric tropical diabatic heating in the upper air global circulation during the austral summer. The only physical processes involved are linear and non-linear dissipation and a heat source induced into the model. It is given that the radiation heat and the sensible heat fluxes are neglectable compared to the latent heat, so that the diabatic heating can be assumed to be solely the latter. The model is initialized horizontally homogeneous from a basic state at rest, and is integrated for a 20-day period. Experiments were made for the months of February 1989, 1997 and 1998, with forcing fields derived from OLR and precipitation values, between 30^oS and 30^oN and then between 60^oS and 60^oN. It was found that the upper tropospheric cyclonic vortex in Northeast Brazil downstream from the Bolivian High only appears as a closed low pressure system in the latter experiment, thus showing the importance of the SACZ in the establishment of this pattern