摘要
由于城市环境对污染扩散的影响主要包括热力作用和动力作用,以苏州市为例,利用南京大学空气质量预报系统(NJU-CAQPS),设置存在热岛影响和消除热岛影响两组敏感性试验,将城市的热力和动力作用进行区分,研究了城市热岛对苏州污染扩散的影响。结果表明:城市热岛增加了大气不稳定性,产生了向市区辐合的热岛环流,加大了市区上空的垂直速度,增加了城市大气的扩散能力。城市热岛总体上使地面污染物浓度下降,城区PM_(10)和PM2.5减少约5×10-9kg·m-3,城区气溶胶各成分浓度及空气质量指数AQI都有不同程度的减少,而地面能见度则相应增加,城市热岛使市区能见度增加约0.5 km。在180 m高度以上,城市热岛使PM_(10)和PM2.5浓度上升,气溶胶各成分都有不同程度的增加。在400 m高度左右,城市热岛环流可使PM_(10)和PM2.5增加,最大可达11×10-9kg·m-3和9×10-9kg·m-3左右,同时使水平能见度下降。城市建筑的动力效应可大幅度降低市区风速,使大气扩散能力减弱,热岛作用(热力作用)和建筑的动力作用相反,但热岛对污染扩散的有利作用小于建筑动力学效应的不利作用。
Urban heat island is the most typical manifestation of the impact of urbanization on the urban climate.The main reason for this phenomenon is that the economic and social development of human beings has changed the nature of the underlying surface. The urban heat island（ UHI） would affect the urban pollution diffusion because of the changes of urban thermal environment and urban wind field caused by UHI circulation. The effects of urban environment on the pollution diffusion mainly include both thermal and dynamic processes. In this paper,urban air quality mode of Nanjing University（ NJUCAQPS） was used to study the influence of urban heat island on the pollution diffusion in Suzhou by two group sensitive tests which separate out the urban thermal and dynamic effects. The results showthat the urban heat island increase the atmosphere instability and arise the urban heat island circulation,which convergence to the urban area and increase the vertical velocity in the urban. The net effect of urban heat island is increase the diffusion capability of pollution. The urban heat island would decrease the pollution concentration near the surface,for example,with a reduction of 5×10-9kg ·m-3of PM10 and PM2. 5in urban area,and with a decreasing tendency of urban aerosol species and AQI at different level. On the contrary,the urban heat island would increase the visibility near surface with the extreme value of 0. 5 km. Above 180 meters height,PM10 and PM2. 5and the main aerosol species are increased by the effect of urban heat island. At400 m altitude,the increase of PM10 and PM2. 5can reach the values of 11 and 9×10-9kg ·m-3respectively. Dynamic effects of urban architectures significantly decrease the wind velocity atmospheric diffusion capacity in urban area,while the heat island effects（ thermal effects） are opposite to the dynamic effects of architectures,but effects of heat island on pollution diffusion are less than the effects of dynamic effects of urban.
出处
《高原气象》
CSCD
北大核心
2016年第6期1584-1594,共11页
Plateau Meteorology
基金
国家自然科学基金资助项目(41305006)
苏州市气象局重点支持项目(SZ200703)
关键词
城市热岛
污染扩散
城市热力学效应
城市动力学效应
Urban heat island
Pollution diffusion
Urban thermodynamic effect
Urban dynamics effect
