拉曼激光雷达探测合肥地区夏秋季边界层气溶胶的光学性质

Optical Properties of Aerosol in Planetary Boundary Layer Measured by Raman Lidar at Hefei in Summer and Autumn

研制了一台拉曼-米-瑞利散射多参数大气探测激光雷达系统,利用其拉曼-米散射通道,实现了边界层内532 nm大气气溶胶消光系数、后向散射系数和消光后向散射比(激光雷达比)的定量测量。利用研制的激光雷达,对合肥地区夏秋季气溶胶光学性质进行了常规观测,观测结果显示,激光雷达比垂直廓线没有明显的突变,说明夜间近地面气溶胶混合得较均匀,并且微物理性质相同。夏季气溶胶激光雷达比平均值为(64.4±6.1)sr,相对较大;秋季平均值为(51.5±5.1)sr,相对较小;夏秋季气溶胶激光雷达比总体变化不大。夏秋季气溶胶激光雷达比稍有不同的原因,可能与气象因素或者气溶胶组成成分略有变化有关。在夏秋各自季节内,激光雷达比各天观测结果变化较小,说明在同一季节内,气溶胶的微物理性质和组成成分相同。整个试验期间观测的激光雷达比在43～72 sr之间,总平均值为57.9 sr;初步判断,处在污染型陆地型气溶胶激光雷达比的范围内。

A Raman-Mie lidar（RML） has been developed for measuring the extinction coefficient,backscattering coefficient and lidar ratio of atmospheric aerosols.Planetary boundary layer（PBL） aerosols were investigated with the lidar system during summer and autumn,2009 at Hefei area.Result shows that during the experiment,remarkable variety dose no exist in the vertical profiles of lidar ratio,which means vertical distribution of aerosols in the PBL has a uniform mixture state and the same microphysical properties.Average value of lidar ratio is 64.4±6.1 sr in summer,which is a little higher than that in autumn with a value of 51.5±5.1 sr,this difference may caused by the change of particle component in the PBL,or the meteorologic factor.Lidar ratio does not change too much in the same season,especially in autumn.During the experiment,lidar ratio accumulated from 43 to 72 sr,with a mean value of 57.9 sr,which means particles in the PBL at Hefei area could be polluted continental aerosols.