Development of a Single－Layer Urban Canopy Model and Numerical Experiments

This paper introduces the Town Energy Balance (TEB) scheme into a single layer urban canopy model developed by Nanjing University (NJU UCM-S). The TEB scheme is an advanced surface energy balance scheme in the world. The energy fluxes at the local scale of 1 km2 area of Nanjing City are simulated with the TEB scheme. The verification results show that every component of urban surface energy balance is well simulated and the TEB scheme is suitable for Chinese cities similar to Nanjing. Moreover, the albedo of building surface material has a great influence on the simulated results with the TEB scheme. Based on these studies, the TEB scheme is successfully coupled with a regional boundary layer model (NJU_RBLM) developed by Nanjing University. In order to compare the simulation ability between the TEB scheme and the traditional SVAT scheme in the NJU_RBLM, two cases for different seasons have been simulated by the NJU_RBLM and the simulation results are compared with observation data. The results indicate that the coupled model improves the simulation of NJU_RBLM evidently, especially to the thermal process and the surface flux. Furthermore, the differences of surface energy budget and Urban Heat Island (UHI) phenomenon modeled by these two schemes show that the TEB scheme has stronger ability in modeling UHI than the SVAT scheme.