Utilizing the Coupled WRF/LSM/Urban Modeling System with Detailed Urban Classification to Simulate the Urban Heat Island Phenomena over the Greater Houston Area

We have developed the coupled Unified Noah land-surface model with a single-layer urban canopy model (UCM) for the Weather Research and Forecasting (WRF) modeling system, and used it to investigate the interactions among urban heat island, sea-breeze circulations, and rural natural landscape and their collective influence on the boundary layer thermodynamic structures for the Greater Houston area for the selected 25 August 2000 case. The detailed description of urban geometry in UCM allowed us to explore the incorporation of a more detailed urban classification including commercial/industrial/transportation, high density residential, low density residential, and urban/recreational grasses, which is critical for capturing the fine-scale heterogeneity in an urban environment. Model simulations results show that the coupled system is able to reproduce, to a large degree, urban-scale temperature and pressure perturbation caused by different types of urban landuse and the overall effects of urban heat island on diurnal cycle of surface temperature, humidity, and wind field. These simulations are verified against available observations.