摘要

Weather Research and Forecasting (WRF) modeling system coupled with Noah land surface model and single layer urban canopy model was improved and optimized. Performances of the modeling system before and after optmization were examined, and diurnal variation of features of urban boundary layer was analyzed, through the numerical study of clear day during 6th and 7th Aug, 2010 over Beijing area. Furthermore, the impacts of urban underlying surface in Beijing and Tianjin on sea breeze were studied through two groups of model sensitivity tests using optimized modeling system. The results show that the optimization can evidently improve the performance of modeling system in the case study in the article. The modeling system can simulate the features of diurnal variation of summer boundary layer in Beijing generally well. Accurate geography data, such as land use and land cover classification information, play a very important role in improving the accuracy of model results. Beijing city and Tianjin city have obvious impacts on the evolution of sea breeze. As the sea breeze penetrating inland, the cities can pose an obstacle to the landward advance of sea breeze current, strengthen the horizontal convergence of wind and vertical updraft. The urban underlying surface in Beijing can also produce faster penetration with stronger intensity of sea breeze before it reaching the city, and increase the lifecycle and inland penetration distance of sea breeze after it passing over the city.