Effects of Baroclinic Waves on the South Atlantic convergence zone

The South Atlantic Convergence Zone (SACZ) is a summertime NW-SE oriented region of enhanced convection and precipitation that extends from the ITCZ convection that is anchored over the Amazon region into the South Atlantic Ocean.

Previous studies have suggested that the origin and position of the SACZ are a result of the interaction between ITCZ convection in the Amazon basin, midlatitude baroclinic systems, and, to a lesser degree, the Andes Cordillera.

Our approach to studying the role of each of the above processes in producing the SACZ is twofold. First, we analyze the results of numerical simulations with a dry, multilayer global model forced by idealized diabatic heating functions that mimic the effects of solar radiation and tropical convection. Next, we analyze the results of more realistic simulations performed with a General Circulation Model that includes parameterizations of radiative effects and moist processes as well as a fully interactive land-surface model. The latter are carried out using a stretched horizontal grid approach which allows for high resolution over South America.