A Mechanical Drag Coefficient Formulation and Urban Canopy Parameter Assimilation Technique for Complex Urban Environments

A mechanical drag coefficient formulation was implemented into the Building Effect Parameterization + Building Energy Model system coupled with the mesoscale Weather Research Forecasting model to improve the representation of the wind speed in complex urban environments. Previously, this formulation had been assessed only against spatially-averaged results from computational fluid dynamical simulations in idealized urban configurations. The main objective is to evaluate its performance over a real city. The introduction of a drag coefficient that varies with the building plan-area fraction increases the accuracy of the mesoscale model in predicting surface wind speed in complex urban environments (i.e. New York City) particularly in areas with tall buildings. Additionally, a methodology to implement local building information and a new land-cover land-use distribution is proposed that improves the representation of the urban morphology.