地形对宜昌市大气污染特征及扩散条件影响  

Influence of Terrain on Air Pollution Characteristics and Diffusion Conditions in Yichang

作　　者：成勤 岳岩裕 罗剑琴[1] 毛成忠 王清龙 饶少林 Cheng Qin;Yue Yanyu;Luo Jianqin;Mao Chengzhong;Wang Qinglong;Rao Shaolin(Yichang Meteorological Office of Hubei Province,Yichang 443000,China;Jinsha National Atmospheric Background Station,Wuhan 430074,China;Wuhan Regional Climate Center,Wuhan 430074,China;Yichang Environmental Monitoring Station,Yichang 443000,China)

机构地区：[1]宜昌市气象局,湖北宜昌443000 [2]金沙国家大气本底站,武汉430074 [3]武汉区域气候中心,武汉430074 [4]宜昌市环保监测站,湖北宜昌443000

出　　处：《气象与环境科学》2024年第5期86-94,共9页Meteorological and Environmental Sciences

基　　金：湖北省自然科学基金项目(2023AFD106);湖北省气象局科技发展基金项目(2020J02、2022Y17)。

摘　　要：利用2016-2020年气象与大气环境监测资料,分析宜昌市三面环山地形对PM_(2.5)、PM_(10)和O_(3)三种主要大气污染物分布和其大气扩散条件的影响,结果表明:(1)三种污染物中,PM_(2.5)污染最严重,O_(3)污染天数少于PM_(10)污染天数,但污染超标程度高于PM_(10)的超标程度。受地形、植被及人类活动影响,宜昌市“喇叭口”地形内大气污染最重。(2)在地形和区域输送的影响下,“喇叭口”内易形成大气污染。冬季颗粒物为主要污染物,污染路径主要为东北路径和偏东路径,潜在源区主要为河南北部和东部、荆门、荆州。夏季O_(3)为主要污染物,污染轨迹主要为偏南和偏东路径,潜在源区为江汉平原和宜昌南部。(3)地表风速与PM_(2.5)、PM_(10)浓度负相关,但受传输过程影响,平均风速大于3.3 m·s^(-1)时,PM_(2.5)、PM_(10)浓度波动较大;与O_(3)浓度正相关,但在平均风速大于2.1 m·s^(-1)时,O_(3)浓度随风速增大而减小。受“喇叭口”地形影响,偏东风为造成宜昌城区PM_(2.5)污染的主风向。受长江河谷地形影响,NW风和E风易造成宜昌城区O_(3)浓度升高。(4)降水对污染物有湿清除作用,降水量与污染物浓度负相关;但降水量小于5 mm时,可能出现PM_(2.5)浓度成倍增长的情况;降水量大于25 mm时,PM_(10)的负清除率占比有所上升;降水对O_(3)的正清除率占比最高,但平均清除率不高。Meteorological and environmental monitoring data from 2016 to 2020 are used to analyze the influence of mountain terrain on the distribution and diffusion conditions of PM_(2.5),PM_(10) and O_(3) in Yichang,Hubei Province.The results show that:(1)Among the three pollutants,PM_(2.5) pollution is the most serious,the O_(3) pollution days are fewer than PM_(10) pollution days,but the pollution degree of O_(3) is higher than PM_(10).Affected by the topography,vegetation and human activities,the air pollution in the“Horn mouth”terrain of Yichang City is the heaviest.(2)Under the influence of terrain and regional transport,air pollution is easily formed in the“Horn mouth”.In winter,particulate matter is the main pollutant,transported mainly from northeast and east directions.The potential source areas are mainly in the northern and eastern parts of Henan Provine as well as in Jingmen and Jingzhou.In summer,O_(3) is the main pollutant,and its pollution tracks are mainly from the south and east directions,with Jianghan Plain and Southern Yichang being its potential source areas.(3)Surface wind speed is negatively correlated to PM_(2.5) and PM_(10) concentrations,but when the average wind speed is faster than 3.3 m·s^(-1),the concentrations of PM_(2.5) and PM_(10) fluctuate greatly.Wind speed is positively correlated to O_(3) concentration,but the correlation is negative when the average wind speed is>2.1 m·s^(-1).Under the influence of the“Horn mouth”terrain,the easterly wind is the main wind causing PM_(2.5) pollution in Yichang.With the terrain of the Yangtze River valley,the O_(3) concentration in Yichang urban area might be raised when northwesterly wind and easterly wind blow.(4)Precipitation has a wet removal effect on pollutants,and it is negatively correlated to pollutant concentrations.However,when precipitation is less than 5 mm the PM_(2.5) concentration may increase exponentially.When precipitation exceeds 25 mm,the proportion of negative removal rate of PM_(10) might increase.The positive remov

关 键 词：地形 大气污染特征 气流轨迹 平均风速 盛行风向 湿清除 

分 类 号：X16[环境科学与工程—环境科学]