Calculation of wind in a Tokyo urban area with a mesoscale model including a multi-layer urban canopy model

The wind velocity in an urban area calculated with a mesoscale meteorological model without an urban canopy model is often overestimated, even when a large value of aerodynamic roughness is specified on the surface. In this paper, the results of a mesoscale model combined with a multi-layer urban canopy model are compared to those of a model without an urban canopy model and with observations. The mesoscale model used here is the AIST-MM. The model is twice-nested, and a 2 km grid is used in the inner model. The model was applied in the vicinity of Tokyo, Japan, and a multi-layer canopy model was combined into 145 grids of the 23-ward area of Tokyo in the inner model. The wind velocity calculated with the urban canopy model is significantly improved near the tops of high buildings and near ground level in residential areas.