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  

Numerical study for the effects of the land cover variations on the sulfur dioxide diffusion and the meteorological parameters in Wuhan City

作　　者：蒋宁洁 王繁强[2] 刘学春 张轩 赵海军 JIANG Ning-jie WANG Fan-qiang LIU Xue-chun ZHANG Xuan ZHAO Hai-jun(Hubei Wuhan Meteorological Bureau, Wuhan 430040, China Shanxi Meteorological Administration, Xi＇an 710014, China Shandong Linyi Meteorological Bureau, Linyi 276004, Shandong, China)

机构地区：[1]湖北省武汉市气象局,武汉430040 [2]陕西省气象科学研究所,西安710014 [3]山东省临沂市气象局,山东临沂276004

出　　处：《安全与环境学报》2016年第6期270-276,共7页Journal of Safety and Environment

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。The paper is to present the investigation results we have gained on the characteristic features of the sulfur dioxide dif- fusion and meteorological parameters in Wuhan City, central China, by coupling a MM5 mesoscale model with the CALMET diag- nostic model in hoping to produce a meteorological field of the boundary layers in the scenario with the fast expansion of urban house construction from 65 km2 in 1970s to 106 km2 till the time being. We have set up four comparatively larger SO2 emission sources as the point sources according to the demand of CALPUFF to pursue the changing scenario of the influential areas of sulfur dioxide diffusion far （near） with small （large） changes of isoline gradient as the result of the suburban area expansion. Thus, we have found that, in both of the scenarios, the seasonal average daily regional maximum dispersion concentration rate turns to be the highest in summer but lowest in winter due to the strongest and weakest energy transformation between the ground surface and the atmospheric conditions in the corresponding seasons. Howev- er, no significant difference has been found for the hourly variation of hourly regional maximum concentration rates. The increas- ing area of suburban areas or construction sites reveal no obvious influence on the horizontal wind fields near the surface and atmospheric stability, though the emission rates may have greatly increased the hourly mixing layer height in the typical days. This indicates that the increased heating effect of the earth＇s surface has been found in larger suburban or industrial areas due to the expansion of the suburban and residentially constructive areas.

关 键 词：环境科学技术其他学科 MM5/CALPUFF 数值模拟 污染扩散 气象条件 

分 类 号：X26[环境科学与工程—环境科学]