基于颗粒物激光雷达的南充市一次沙尘污染过程分析

摘要

利用环境空气颗粒物自动监测数据、近地面气象数据和颗粒物激光雷达资料对南充市主城区2016年5月12日的沙尘气溶胶污染天气过程进行分析,并利用HYSPLIT模式对沙尘气溶胶的来源进行了模拟分析.结果表明:来自新疆盆地的沙尘气溶胶经高空远距离输送到达四川盆地上空后沉降造成南充市主城区的PM10和PM2.5浓度极显著升高,PM2.5/PM10值极显著降低;沙尘天气过程中,风速、气温、相对湿度、气压、能见度和大气边界层高度等气象因子发生变化并对环境空气中颗粒物浓度产生影响,其中风速与PM:5和PM10浓度间显著正相关,与PM2.5/PM10值间显著负相关;颗粒物激光雷达连续监测到整个沙尘气溶胶沉降过程,与地面环境空气自动监测数据变化趋势一致.在对盆地城市沙尘天气的环境空气质量进行预警预报时,将历史环境空气质量自动监测数据与常规气象因子数据、颗粒物雷达资料和后向轨迹等资料进行综合分析,能进一步提高沙尘天气条件下的空气质量预警预报准确度.%Based on ambient air automatic monitoring data of particulate matter,near surface meteorological data and particulate matter lidar data,the pollution process of dust aerosol on 12th May,2016 in main urban area of Nanchong City was analyzed.The source of dust aerosol was simulated and analyzed with the HYSPLIT model.The results showed that the concentrations of PM10 and PM2.5 were extremely and significantly increased,the ratio of PM2.5/PM10 was extremely and significantly decreased in the main urban area of Nanchong City,which were caused by the long-distance transportation and deposition of dust aerosol from Xinjiang basin.During the process of dust weather,meteorological factors (such as wind speed,air temperature,relative humidity,air pressure,visibility and the PBL's height) changes and influenced the concentration of PM10 and PM2.5.In addition,wind speed had significant positive correlation with PM10 or PM2.5 and significant negative correlation with PM2.5/PM10.The whole process of dust aerosol transportation and disposition had been monitored by the Particulate LiDAR,and the results was consistent with the variation tendency of automatic monitoring data of particulate matter.During the warning and forecasting of ambient air quality about sandstorms in basin cities,a comprehensive analysis will be conducted on the base of historical automatic monitoring data of ambient air quality,the meteorological factors data,Particulate LiDAR data and back trajectory,which can improve the accuracy of the early warning and forecasting of ambient air quality.