基于偏振激光雷达对远距离传输沙尘在局地混合过程的观测研究

利用国控站点的 PM2:5 和 PM10 含量, 分析了一次蒙古地区沙尘的远距离传输事件; 并结合 532 nm 偏振激光 雷达的观测结果, 研究了沙尘在武汉地区的混合过程。研究表明, 在这次沙尘事件中, 边界层顶的夹卷过程和边界层 内的对流混合对沙尘在局地的分布起到重要的作用。在沙尘输入初始时期, 沙尘高度约为 1 km, 主沙尘层经过边界层 顶的夹卷过程进入边界层内, 并在对流混合作用下在边界层内最终呈现近似均匀的高度分布。在沙尘事件末期, 北方 污染的输入带来约 4300 t 城市气溶胶, 约为军运会期间武汉地区城市气溶胶总含量的十倍。

Investigation of Entrainment of Transported Dust into Local Planetary Boundary Layer with Polarization Lidar

A transported dust case was investigated by using the data of PM2:5 and PM10 from ground monitoring stations and the observation results with 532 nm polarization lidar. Entrainment and convective mixing processes, which were found to play an important role in re-distributing the dust particles, were depicted in detail. At the early stage of the dust episode, dust particles were lifted above 1 km. After the evolution of planetary boundary layer at daytime, the dust particles were entrained into the boundary layer and evenly distributed by convective mixing. At the end of the dust case, the pollution from North China Plain arrived at Wuhan bringing about 4300 tons of anthropogenic aerosols, which is about ten times of the total content of urban aerosols in Wuhan during the 7th CISM Military World Games.