西南山区大气污染扩散的定点观测与模式评估  

On-site Observation and Modelling Evaluation of Air pollutant Dispersion over Mountainous Area in Southwestern China

作　　者：刘清[1] 刘丽 杨富燕 高鹏 廖瑶 吴有恒 LIU Qing;LIU Li;YANG Fuyan;GAO Peng;LIAO Yao;WU Youheng(Guizhou Climate Center,Guiyang 550002,China;Guizhou Ecometeorology and Satellite Remote Sensing Center,Guiyang 550002,China;Guizhou Key Laboratory of Mountainous Climate and Resources,Guiyang 550002,China)

机构地区：[1]贵州省气候中心,贵州贵阳550002 [2]贵州省生态气象和卫星遥感中心,贵州贵阳550002 [3]贵州省山地气候与资源重点实验室,贵州贵阳550002

出　　处：《贵州大学学报（自然科学版）》2023年第5期96-105,共10页Journal of Guizhou University:Natural Sciences

基　　金：贵州省山地气候与资源重点实验室横向项目(1740409802);山地生态气象遥感应用系统(FY-3(03)-AS-12.13)。

摘　　要：针对山区局地污染源的大气扩散,通过定点气象观测与数值模拟相结合的污染评估技术,采用区域模式与局地模式相嵌套的高分辨率区域空气质量模拟系统RegAQMS,模拟了一个西南山区磷化工工业园所在区域三维气象要素场、大气边界层湍流场以及污染物散布的浓度场,分析了山地复杂条件下大气污染物的扩散特性和影响其散布的关键因子。结果表明:区域主要的污染物如SO_(2)小时和日均浓度均未超过国家相关标准且有较大盈余,但在源区附近山体表现出较高的长期平均浓度,模拟时段总平均浓度占比标准份额高达87.7%。区域偏东和东南风极高的出现频率61.8%、较低的风速(如≤2 m/s风速频率43.1%)、离源近距离处敏感的下风向有相当高度山体的阻挡、大气稳定层结(逆温和贴地逆温较高的频率63.4%和27.2%)等是导致长期高值平均浓度的主要原因。与观测浓度的对比表明:RegAQMS能较好地描述该区域污染物的实际分布,模拟与观测的小时浓度相关达0.47,但整体有所高估,误差可能来源于采样时间的不同、排放源的变动、小风条件下平均风向的定义与扩散强度估计的不确定性等。Atmospheric dispersion of air pollution on mountainous area was studied with numerical simulation method combined with meteorological observations on site.In the case of a phoschemical industrial park in the southwestern mountains of China,three-dimensional meteorological elements and turbulent parameters at atmospheric boundary layer and further air pollutant concentrations in this area were simulated with the Regional Air Quality Model System(RegAQMS),in which a high-resolution local model suitable for mountainous area was nested in a regional dispersion model.The diffusion characteristics of air pollutants over this mountainous topography were then summarized by diagnostic analysis on key factors influencing its distribution.The results show that hourly and daily average concentration of major pollutants,such as SO_(2),are well within the Class 2 of the National Ambient Air Quality Standard,while the long-term average concentration presents quite high around a hill near the industrial park and at a ratio of 87.7%to Class 2 limit value.The east and southeast winds at a high frequency of 61.8%,low wind speeds(≤2 m/s)occurring with 43.1%in all hours,blocking terrain in the sensitive leeward near the source,and stable atmospheric conditions(63.4%frequent inversion layers especially ground inversions of 27.2%)are the main reasons of high concentration over long period of time.By comparing the results with the observed concentrations,RegAQMS is proved to well describe the actual distribution of pollutants in this area.The Pearson correlation of hourly concentration is 0.47,although overall the model overestimates observations.Some inconsistencies between simulated and observed concentrations may result from different sampling time,variation of emission sources,and uncertainties in the definition of mean wind direction and estimation of dispersion intensity under low wind conditions.

关 键 词：大气污染 扩散模拟 气象观测 山区 

分 类 号：X16[环境科学与工程—环境科学]