A modeling analysis of urban canopy parameterization representing the vegetation effects in the megacity of São Paulo

• An urban-vegetation parameterization with weighting turbulent fluxes is evaluated.
• Inclusion of urban vegetation provides better accuracy for mesoscale simulations.
• Modeling vegetation is important even for cities with low index of green areas.

The representation of the influence of vegetation on meteorological variables inside the urban canopy is a modeling challenge. The interaction of vegetation canopy parameterization for urban regions in mesoscale modeling was implemented and analyzed in this work. The BRAMS model equipped with the TEB was used to simulate a calm wind and clear sky period in the Metropolitan Area of São Paulo. The impact of vegetated areas on cities was estimated by calculating the surface fluxes due to vegetation and artificial materials, weighing individual contributions by using each component fraction inside a model grid. An evaluation of the vegetation impact on atmospheric conditions was made by comparing simulated temperature and specific humidity with surface observations, atmospheric sounding values and land-surface temperature product retrieved from MODIS/TERRA. The inclusion of vegetation clearly improves the simulated air temperature, the vertical structure of the urban boundary layer and the calculation of surface fluxes. Although some improvements in the model are still necessary, it is clear that the model is very sensitive to the presence of the vegetation and continuous efforts should be made to better understand the related process and to provide better tools for urban planning and other important activities in urban areas.