四川盆地降水对PM_(2.5)和PM_(10)的清除作用分析  

Scavenging effect analysis of precipitation on PM_(2.5) and PM_(10) in Sichuan Basin

作　　者：郑飒飒 王维佳[1,2,3] 刘东升 苗红妍[4] ZHENG Sasa;WANG Weijia;LIU Dongsheng;MIAO Hongyan(Weather Modification Office of Sichuan Province,Chengdu 610072;Sichuan Provincial Meteorological Service,Chengdu 610072;Cloud-Precipitation Physics and Weather Modification Key Laboratory,CMA Beijing 100081;Meteorological Administration Training Center Liaoning Branch,Shenyang 110166)

机构地区：[1]四川省人工影响天气办公室,成都610072 [2]四川省气象局,成都610072 [3]中国气象局云降水物理与人工影响天气重点开放实验室,北京100081 [4]中国气象局气象干部培训学院辽宁分院,沈阳110166

出　　处：《暴雨灾害》2024年第5期607-616,共10页Torrential Rain and Disasters

基　　金：四川省科技计划项目(2019YJ0621,2023YFS0442);高原与盆地暴雨旱涝灾害四川省重点实验室科技发展基金项目(SCQXKJQN2020049)。

摘　　要：四川盆地是中国空气污染最严重的区域之一,为研究降水对四川盆地PM_(2.5)、PM_(10)的清除作用,利用2016—2021年四川盆地90个环境监测站PM_(2.5)、PM_(10)质量浓度观测资料和17个地面气象站观测资料,首先分析了降水对四川盆地PM_(2.5)、PM_(10)空间分布的影响;然后基于描述降水前后气溶胶粒子质量浓度变化的清除率,揭示了降水强度、时长对PM_(2.5)、PM_(10)清除效果的影响;最后,利用雨滴谱分布、雨滴大小、下降末速度等雨滴谱参量计算污染物的清除系数,分析了四川盆地4次污染事件中降水对PM_(2.5)、PM_(10)的清除效果。结果表明:(1)四川盆地降水影响PM_(2.5)、PM_(10)空间分布,降水量越大、降水持续时间越长,清除率越大,清除效果越明显;(2)大雨个例中,降水持续时间大于6 h后,清除率对降水持续时间增加不敏感;(3)当雨滴直径、雨滴总个数和分钟雨强出现峰值,雨滴谱加宽变强后,PM_(2.5)、PM_(10)质量浓度快速降低;(4)清除系数对PM_(2.5)和PM_(10)质量浓度变化具有指示意义,当清除系数峰值达10 h^(-1)以上,降水对PM_(2.5)和PM_(10)清除效果显著。The Sichuan Basin is one of the most severely air-polluted regions in China.To study the scavenging effect of precipitation on PM_(2.5) and PM_(10) in Sichuan Basin,the PM_(2.5) and PM_(10) mass concentration data from 90 environmental monitoring stations and observation data from 17 ground meteorological stations in Sichuan Basin from 2016 to 2021 were used.First,the effects of precipitation on the spatial distribution of PM_(2.5) and PM_(10) in the Sichuan Basin were analyzed.Then,the influence of precipitation intensity and duration on PM_(2.5) and PM_(10) removal effects was revealed based on the removal rates of aerosol particle mass concentration changes before and after precipitation.Finally,by calculating the removal coefficients using the raindrop spectral distribution,raindrop sizes,and end-of-fall velocities,the removal effects of precipitation on four PM_(2.5) and PM_(10) pollution events in the Sichuan Basin were investigated.The results are as follows:(1)In the Sichuan Basin,precipitation affects the spatial distribution of PM_(2.5) and PM_(10).The greater the precipitation amounts and the longer the duration of precipitation,the greater the removal rates and the more significant the scavenging effect.(2)In cases of heavy rainfall,removal rates are not sensitive to increases in precipitation duration when it exceeds 6 hours.(3)When the raindrop diameter,the total number of raindrops,and the minute rain intensity peak,and the raindrop spectra broaden and intensify,rapid decreases of PM_(2.5) and PM_(10) mass concentrations occur.(4)The removal coefficients are indicative of variations in PM_(2.5) and PM_(10) mass concentrations.When the peak removal coefficients are above 10 h^(-1),the scavenging effect of precipitation on PM_(2.5) and PM_(10) is significant.

关 键 词：PM_(2.5) PM_(10) 降水 雨滴谱 清除作用 

分 类 号：P426.62[天文地球—大气科学及气象学]