武汉市下垫面变化对大气污染物扩散和气象要素影响的数值模拟

发布时间：2018-03-24 13:39

本文选题：环境科学技术其他学科　切入点：MM/CALPUFF　出处：《安全与环境学报》2016年06期

【摘要】：大规模的土地覆被变化改变了地区地表环境的能量收支平衡,造成大气边界层内流场特征和湍流特征的改变,使得区域内污染物的扩散、转化和积累等规律也发生变化。根据CALPUFF的格式要求,将武汉市SO_2排放量较大的源设置为点源,耦合中尺度气象预测模型(MM5)和气象诊断模型(CALMET)模拟边界层气象要素场。在边界层气象背景下,采用中尺度气象模型(MM5)和空气质量预测模型(CALPUFF)对武汉市空气中污染物SO_2的扩散进行数值模拟分析。重点分析了武汉市主城区下垫面城镇建设面积由70年代的65km2增加到目前的106 km2情景下,大气污染物扩散和气象要素的特征变化。研究区域下垫面城市面积增加后,大气污染物扩散特征为主导风下(上)风向影响范围较远(近),等值线变化梯度较小(大)。两种下垫面情况下,区域SO_2最大日质量浓度的季平均值夏季最大、冬季最小,是由于地气能量的交换在夏季最强、冬季最弱;区域内小时最大质量浓度的逐时变化无明显差异。下垫面面积增加对近地面水平风场、稳定度的影响不显著;对混合层高度的影响较为显著,典型日小时混合层高度均有所增加,表明由于城镇面积扩大,市中心、工业区随之扩大,增大了地表受热面积,混合层高度变高。
[Abstract]:Large-scale land cover change has changed the energy balance of the surface environment in the region, resulting in the change of the characteristics of the flow field and turbulence in the atmospheric boundary layer, and the diffusion of pollutants in the region. The laws of transformation and accumulation have also changed. According to the format requirements of CALPUFF, the sources with large SO_2 emissions in Wuhan are set as point sources. The mesoscale meteorological prediction model (MM5) and the meteorological diagnostic model (CALMET) are used to simulate the boundary layer meteorological element field. A mesoscale meteorological model (MM5) and an air quality prediction model (CALPUFF) were used to simulate and analyze the diffusion of air pollutants in Wuhan City by SO_2. The emphasis was put on the analysis of the area of urban construction on the underlying surface of the main urban area of Wuhan, which increased from 65km2 in the 1970s. Add to the current 106 km2 scenario, The characteristics of atmospheric pollutant diffusion and meteorological elements. After the increase of urban area on the underlying surface of the study area, The diffusion characteristics of atmospheric pollutants are as follows: (1) the wind direction under the dominant wind has a far (near) range, and the variation gradient of isoline is relatively small. In the case of two underlying surfaces, the seasonal average value of the maximum daily mass concentration of SO_2 in the region is the largest in summer and the minimum in winter. The reason is that the exchange of ground air energy is the strongest in summer and the weakest in winter, and there is no obvious difference in hourly variation of maximum mass concentration in the region. The increase of the area of underlying surface has no significant effect on the horizontal wind field near the ground. The influence on the height of mixing layer is obvious, and the height of mixing layer increases in typical day hour, which indicates that due to the expansion of urban area, the city center and the industrial area, the surface heating area increases and the mixing layer height becomes higher.
【作者单位】：湖北省武汉市气象局;陕西省气象科学研究所;山东省临沂市气象局;
【分类号】：X51;X16

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