Investigating the impact of convection permitting simulations in the mesoscale structures associated with cyclones in south-southeast of Brazil

Abstract

he cyclonic activity in their various phases (tropical, subtropical and extratropical) in the southwest of the South Atlantic Ocean often produces heavy rains, strong winds, sudden drops in temperature, among other abrupt changes. The eastern south-southeast of Brazil concentrates large metropolitan areas, being vulnerable to the impacts of intense events associated with cyclones. Although there has been considerable progress in understanding these systems, numerical simulations still have difficulties in reproducing the rainfall and intense winds caused by cyclones. In this way, the objective of the project is to evaluate the ability of simulations at convection permitting scale (CPM - spatial resolution ~ 4 km and cumulus convection solved at grid scale) in the reproduction of mesoscale structures associated with cyclones producing intense events (rain and wind) in the south-southeastern Brazil. Two types of cyclones affecting the region will be analyzed, one subtropical and the other extratropical. In methodological terms, WRF (Weather Research and Forecast) will be used for the CPM simulations, which will be evaluated through comparisons with local observations. It is expected tha resolution refinement and the use of cloud microphysics in CPM simulations may develop the mesoscale environments generating intense events. In addition, the project will be important to student training in the area of numerical modeling of the atmosphere. Finally, the analyzes will contribute to ongoing discussions on the project "Investigating the past and future trends of cyclone formations/transitions over the South Atlantic basin (FAPESP 2022/0547-2)".