Estudo numérico da interação entre uma região urbanizada e a convecção rasa.

Abstract

Some surface processes that determine the energy balance are studied in this work through atmospheric numerical modeling using the Brazilian Developments on the Regional Atmospheric Modeling System - BRAMS model to the Metropolitan Area of Recife – MAR. Through the coupling between the BRAMS model and the Town Energy Budget - TEB scheme together with considering the interaction between shallow cumuli and the radioactive processes, we managed to get a better representation of the surface processes at urban regions. We studied two cases, one of them for a dry period and the other for a rainy episode. To better understand the sole effect of both the urban dynamics as well as the effect of the shallow convection, we used the method of factor separation of Stein and Alpert (1993). Considering the joint effect of the urban dynamics and shallow cumulus produced more realistic results. Depending whether the event is rainy or not, we found that in some cases certain variables are constrained by the shallow convection activity, and in other cases by the urban dynamics. Shallow cumuli reduce the solar radiation that reaches the soil and reduce the solar heating of the near-surface air. On the other hand, shallow cumuli act to warm up the city through the long wave radiation budget. Analyzing the spatial distribution of precipitation, our results suggest that the urban area may contribute to increasing or decreasing the precipitation, depending on the timing of rainy events occurrence.