Avaliação e aplicação de esquema de dossel urbano no modelo meteorológico WRF

Abstract

Natural land cover substitution for buildings and impervious surfaces, besides the development of polluting human activities, are capable of drastically change the surface properties with a consequential interference on local meteorological conditions. Weather Research and Forecasting (WRF) mesoscale model when coupled with urban canopy schemes such as the Building Effect Parameterization (BEP), is able to simulate more realistically urban boundary layer processes, determining heat, moisture and momentum distribution, both horizontal and vertically. Given human agglomeration in urban areas is a worldwide tendency, it is imperative the need to test available tools to analyze the urban coverage influence on the processes that dictate the meteorological conditions formation, of which several essential services rely on. Thereby, this survey had as main objectives to evaluate the effect of BEPs urban canopy scheme coupling to WRF, denotated as uWRF, and its application in the study of the Metropolitan Area of Belo Horizontes (MABH) urban climate, for which just a few numerical modeling studies have been observed. Initially, urban areas of interest were classified in local climatic zones and updated on uWRF database. After model parameterization and validation with measured data, it was observed that a poor land use and land cover representation negatively impacted on the uWRF predicted results, though it has proven its skillness on reducing the usual wind speed positive bias presented by the bulk approach (control). Subsequently, the 2m air temperature outputs and the surface energy fluxes of both model versions were analyzed. It was verified that WRF tends to suppress latent heat flux in the urban classes and to estimate higher ground heat fluxes during daytime, resulting in more pronounced nighttime temperatures, up to 1.1°C, than those calculate by the urban coupled model. It was also proposed a scenario of future growth, in which was simulated sprawling, densification and verticalization of the current urbanized area. It was observed an air temperature increase up to 3.2°C and the intensification of the urban heat island at the south-central region of Belo Horizonte. Finally, it was performed a sensitivity test on the urban module regarding two urban canopy parameters. Despite the mild alterations proposed, the changes in the air and skin temperature were perceptible, indicating that the module is sensitive to the input parameters which, therefore, must be adopted with discretion. It is expected that the limitations and potentialities of both model versions, besides the results herein depicted may contribute to the conduction of subsequent analyzes.