High resolution modeling of the regional climate variability over the Southeast of Brazil

Global changes of climate can potentially affect densely populated regions in the southeast of Brazil. These changes can arise from the variability of drivers such as solar, volcanic, and anthropogenic activities, as well as complex responses related to cloud cover and ocean temperatures. However, the precise function of each driver is still a topic of debate. At regional scale, climate models have been employed to assess the evolution of the climatic parameters and to project future changes. However, high-resolution (5 km) estimates are needed to identify specific areas that are vulnerable to events that could result in heavy rains, flooding, and mudslides. Here we investigate the sensibility of the regional precipitation patterns estimated employing the regional model Eta to the several schemes of cloud microphysics and the Betts-Miller-Janjic convection parameterization. This version of the model Eta is based on schemes of refined slope for the vertical coordinate and non-hydrostatic dynamics. Following other authors, the region model is embedded in the ERA-interim (European Centre for Medium-Range Weather Forecasts-ECMWF) reanalysis. The model free parameters are determined by minimizing the difference between models output and observations of the precipitation variability associated to the passage of could fronts and the south Atlantic Convergence Zone from 2000 to 2010. Additionally, the limitations of the model to assess regional effects of climate change and future strategies to increase its precision are discussed. This work is supported by FAPESP under the grant agreement nos. 2008/58161-1 (PFPMCG - Projeto Temático) and 2011/13976-0.