Detailed Mapping and Modeling of Urban Vegetation: What Are the Benefits for Microclimatic Simulations with Town Energy Balance (TEB) at Neighborhood Scale?

Abstract

Cities develop a specific climate related to their morphology and the materials that constitute them. The addition of vegetation in urban areas induces cooling and shading effects that can modify local climate and thermal comfort conditions. The Town Energy Balance (TEB) urban canopy model offers several configurations for a more or less fine-tuned consideration of natural covers and associated physical processes in the urban environment. This study aims to evalu-ate the sensitivity of TEB to the representation of vegetation and the resolution of the chosen databases in the simulation of microclimatic variables, at the scale of a heterogeneous urban neighborhood located in Toulouse, France. First, the effect of the improved description of the vegetation input to the model is highlighted by comparing the results obtained with a readily available national database and then with a very-high-resolution satellite-derived vegetation database. Second, the two vegetation parameterizations, with or without explicit tree stratum, that are available in the TEB model are evaluated and compared. Measurements carried out on specific routes and stop points in a neighborhood of Toulouse allowed microclimatic variables to be evaluated. Results show that refining the vegetation database can somehow improve the modeling of air temperature. As a result of enhancing the vegetation description in the model, that is, physical processes associated with the presence of trees in urban canyons, the air temperature, but also the wind and the thermal comfort index, are better simulated. These results are encouraging for the use of TEB as a decision support tool for urban planning purposes.