中文摘要：

采用大涡模拟方法，通过数值求解可压缩流体的动力学方程和欧拉型的浓度扩散方程，建立了不同的地表模型，将城市地表差异等因素作为地面热通量的边界条件引入，得到了简单区域上的温度场和流场的三维结构，证实了城乡地表差异是引起热岛现象的根本原因之一，成功再现了城市热岛现象，并研究了城市热岛效应的存在对污染物扩散的影响。

英文摘要：

The compressible hydrodynamic Navier-Stokes equations and concentration diffusion Euler equations were established numerically by Large Eddy simulation method. The difference of the ground surface between urban and rural areas was introduced into the model by different surface conditions of heat flux. The temperature field and velocity field were obtained, and the results suggested that the difference of the ground surface should be one of the fundamental reasons that caused heat island phenomenon. The influence of heat island to pollutant transport was studied by solving the scalar transport equation of Euler type.