摘要
为研究北京市气溶胶垂直方向上的分布特征,利用微脉冲激光雷达(MPL)对北京市2015年12月—2016年11月的气溶胶光学特征进行分析,讨论了气溶胶消光系数的季节性特点以及不同污染等级下的垂直分布,并对其影响因素进行了探讨.结果表明:①北京市气溶胶消光系数垂直特征在季节上存在异质性.秋、冬两季近地面1.0 km以下气溶胶消光系数显著增大,最大气溶胶消光系数大于1.0 km^-1;春、夏两季污染日较少,气溶胶消光系数在垂直方向上变化较为平缓.②不同污染等级下气溶胶消光系数的垂直特征差异明显.空气质量为优-良水平时,气溶胶消光系数较低,基本不高于0.7 km^-1;轻-中度污染时,气溶胶消光系数在不同季节差异较大,冬、春两季气溶胶消光系数不超过0.8 km^-1,夏、秋两季在1.0 km^-1左右,部分监测站甚至在1.4 km^-1左右;重度及以上污染时,气溶胶消光系数基本在1.0 km^-1以上,最高可达1.7 km^-1.③105 m处气溶胶消光系数与ρ(PM 2.5)相关性较好.气溶胶消光系数除受ρ(PM 2.5)影响外,还受相对湿度影响较大.夏、秋两季对流层底层大气相对湿度偏高,致使气溶胶消光系数显著高于春季和冬季.研究显示,利用激光雷达可对北京市气溶胶垂直方向分布特征进行有效分析,气溶胶的垂直分布受污染水平和相对湿度的影响呈季节性变化.
In order to determine the vertical distribution characteristics of aerosol in Beijing,micro pulse lidar was used to analyze the aerosol optical properties from December 2015 to November 2016 to explore its extinction coefficient of seasonal characteristics,as well as the vertical distribution at different pollution levels.Furthermore,the influence factors were discussed.The results show that:(1)The vertical distribution of aerosol extinction coefficient has seasonal heterogeneity and it increases significantly below 1.0 km in autumn and winter.The maximum extinction coefficient is larger than 1.0 km^-1.The extinction coefficient changes gently in vertical direction and it seldom happens on spring and summer pollution days.(2)The vertical distribution of aerosol extinction coefficient also has heterogeneity at different pollution levels.On days with excellent or good air quality,the aerosol extinction coefficient is lower than 0.7 km^-1.On days with light or moderate air quality,the extinction coefficient shows obvious seasonal heterogeneity and the extinction coefficient is less than 0.8 km^-1 in spring and winter.But in summer and autumn,the extinction coefficient is close to 1.0 km^-1,and some stations even reach about 1.4 km^-1.On heavily polluted days,the aerosol extinction coefficient is larger than 1.0 km^-1,and the maximum coefficient can reach 1.7 km^-1.(3)The extinction coefficient of aerosol at 105 m is well correlated to PM 2.5 concentration and it is also affected by relative humidity.The relative humidity in the lower troposphere is higher in summer and autumn,which makes the extinction coefficient of aerosol significantly higher than that in spring and winter.The results indicate that the lidar can be used for analyzing the vertical distribution characteristics of aerosol in Beijing effectively.The vertical distribution of aerosols varies seasonally with the influence of pollution levels and humidity.
作者
邱昀
安欣欣
刘保献
鹿海峰
王新辉
王琴
罗霄旭
李令军
QIU Yun;AN Xinxin;LIU Baoxian;LU Haifeng;WANG Xinhui;WANG Qin;LUO Xiaoxu;LI Lingjun(Beijing Municipal Environmental Monitoring Center,Beijing 100048,China;Beijing Key Laboratory of Airborne Particulate Matter Monitoring Technology,Beijing 100048,China)
出处
《环境科学研究》
EI
CAS
CSCD
北大核心
2020年第3期519-525,共7页
Research of Environmental Sciences
基金
国家重点研发计划项目（No.2016YFC0208502)~~
关键词
激光雷达
气溶胶
气溶胶消光系数
垂直分布
影响因子
micro pulse lidar
aerosol
extinction coefficient
vertical distribution
influencing factors
