论文部分内容阅读
Urban heat island (UHI) causes differences of surface thermal characteristics between urban and rural area and may trigger mesoscale circulations,namely,urban heat island circulation (UHIC).UHI and UHIC always impact local planetary boundary layer (PBL) structure and turbulence processes.WRF-LES model (Weather Research and Forecasting model-Large Eddy Simulation) is employed to simulate the PBL characteristics and mesoscale circulations forced by ideal urban heat islands in this paper.The horizontal heterogeneity of UHI distribution is considered and idealized as a cosine function in urban area in our simulations.Results found that UHI heating rate and UHI heterogeneity impact directly on spatial distribution of wind fields; the strong transport of warm air from urban area to rural area at the high level of boundary layer causing more stable atmospheric stratification over rural area; mesoscale heat flux triggered by UHI and UHIC is affected by both UHI intensity and background atmospheric stratification.