苏州城市热岛对污染扩散的影响

发布时间：2018-03-30 17:22

本文选题：城市热岛　切入点：污染扩散　出处：《高原气象》2016年06期

【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。
[Abstract]:Because the influence of urban environment on pollution diffusion mainly includes thermal and dynamic effects, taking Suzhou City as an example, using the air quality prediction system of Nanjing University (Nanjing University), two groups of sensitivity tests are set up, that is, heat island influence and eliminating heat island influence. The thermal and dynamic effects of urban heat island on pollution diffusion in Suzhou are studied. The results show that urban heat island increases atmospheric instability and produces convergent heat island circulation to urban area. The vertical velocity over the urban area is increased, and the diffusion ability of the urban atmosphere is increased. The urban heat island generally reduces the concentration of pollutants on the ground. The density of aerosol components and air quality index (AQI) in urban area decreased to some extent, but the surface visibility increased accordingly. Urban heat island increased visibility in urban area by about 0.5 km. The urban heat island can increase the concentration of PM2.5 and PM2.5, and the composition of aerosol increases to some extent. At the height of 400m, the circulation of urban heat island can increase the number of PM10) and PM2.5, with the maximum of 11 脳 10-9kg m-3 and 9 脳 10-9kg m-3, the maximum value is about 11 脳 10-9kg m-3 and 9 脳 10-9kg m-3, and the maximum is about 11 脳 10-9kg m-3 and 9 脳 10-9kg m-3, respectively. At the same time, the horizontal visibility is reduced. The dynamic effect of urban buildings can greatly reduce the wind speed in urban areas, weaken the atmospheric diffusion ability, and the heat island effect (thermal action) is opposite to the dynamic effect of buildings. However, the beneficial effect of heat island on pollution diffusion is less than that of building dynamics.
【作者单位】：苏州市气象局;南京大学大气科学学院;相城区气象局;
【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)
【分类号】：X16;X51

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