Proper Choice of Urban Canopy Model for Climate Simulations

The Weather Research and Forecasting model (WRF) is coupled with the three types of Urban Canopy Models (UCMs) to predict heat and moisture fluxes from the canopy to the atmosphere. The three UCMs are slab, single-layer, and multi-layer. The WRF-UCMs are applied to investigate the impacts of summer heat on urban climate and characterize the heat island intensity in the Greater Toronto Area (GTA) during the 2011 heat wave period (17th -21st July). The WRF-UCMs are evaluated using simulated hourly air temperature and wind speed results with measurements obtained from various weather stations across the domain of interest. The multi-layer of the urban canopy model (ML-UCM) predicts air temperature and wind speed more accurately comparing to other UCMs. The ML-UCM accounts for the turbulence and multi-reflection within the urban canopy and increases the computation time 30-40% compared to other canopy models (single and slab model).