Summer rainfall in São Paulo, Brazil

Abstract

The project deals with a basic problem related to weather forecasting in the region where the city of São Paulo is located: the large amounts of rainfall in summer which often lead to floods. Rainfall monitoring and its evolution are analysed from the global and large scale perspective by studying the remote influences (teleconnections) and the synoptic systems associated to enhanced rainfall events, and the mesoscale where the formation of convective systems forced by local circulations (topography and land/sea contrasts). This goals are achieved through the use of numerical simulations, diagnostic analysis using data form the operational networks, global analysis, and remote sensing products from radar and satellite. Results form observational campaigns conducted in the past (RADASP Project - FAPESP) are used to test the validity of the numerical simulations. The regional mesoscale modeling system - RAMS - is used for the limited area simulations; global simplified models are used for the teleconnections. The tradition of the group in research involving large scale and mesoscale atmospheric dynamics as well as in remote sensing techniques is the basis for the present work. the main focus of the present work is the South Atlantic convergence zone - SACZ: its relationship with other tropical heat sources like the South Pacific convergence zone - SPCZ, the intertropical convergence zone - ITCZ, and the Amazon convection; its climatology and diurnal variation; its relationship with orographic intensification of rainfall; the formation of enhanced convection embedded in stratiform regions; the influence of surface processes; the fine structure of the associated precipitation. (AU)