Urban Land - Atmospheric Coupling System: Model Development and Applications

Rapid urban expansion and the associated landscape modification have led to significant changes of surface processes in built environment. These changes further interact with the overlying atmospheric boundary layer (ABL) and strongly modulate urban microclimate. To capture the impacts of urban land surface processes on urban ABL dynamics, a coupled urban land-atmospheric modeling framework have been developed. The urban land surface is parameterized by an advanced single-layer urban canopy model (SLUCM) with realistic representations of urban green infrastructures such as lawn, tree, and green roof, etc. The urban boundary layer is simulated by a single column model (SCM) with both convective and stable schemes resolved. This coupled SLUCM-SCM framework can predict the time evolution and vertical profile of different meteorological variables such as virtual potential temperature, specific humidity, CO2 ratio, etc. Overall, this coupled framework is an effective stand-alone predictive tool to assess the impact of changes of urban morphology, hydrothermal properties, and biogeophysical processes on urban microclimate. Furthermore, this framework can be implanted into large-scale models such as Weather Research and Forecasting (WRF) model to assess the impact of urbanization on regional climate.