塔克拉玛干沙尘天气的激光雷达探测个例分析

An Analysis on Detection of a Sand-dust Weather over Taklimakan Desert Based on Polarization Micro-pulse Lidar

利用偏振微脉冲激光雷达对塔中一次沙尘天气过程进行了监测分析，得到沙尘的空间分布结构、变化过程等信息：（1）偏振微脉冲激光雷达对沙尘天气的探测能够区分沙尘暴和浮尘沙尘天气现象；（2）在沙漠近地面发生沙尘暴时段，各高度层沙尘浓度基本上较高，退偏比在0．3～0．4，而在地面发生浮尘开始时段，在4500m以上高度沙尘浓度基本上较高，退偏比在O．3～0．4，而在地面发生浮尘开始和结束时段，在4500m以下高度沙尘浓度相对较低，退偏比在0．2～0-3左右；（3）沙漠近地面发生沙尘天气时，高空沙尘浓度也较高且来源于周边，高空较高浓度沙尘的持续时间长于近地面。

Based on the sand-dust weather monitoring with polarized micro-pulse lidar in Tazhong, the spatial and temporal distribution were obtained： （1）the sand-dust storm and floating dust can be distinguished; （2）the concentration of sand-dust at each level is high in general,and the depolarization ratio is 0.3-0.4 during the period of sand-dust storm, while during the floating dust initial period, that was high above 4 500 m altitude and the depolarization ratio was above 0.3-0.4, but that was rather low below 4 500 m altitude and the polarization ratio is 0.2-0.3 at the beginning and the end of floating dust weather overground; （3）when sand-dust weather generated near surface in the desert, the concentration was high at upper atmosphere level and the sand-dust came from surrounding regions ,yet the duration of high concentration of sand-dust at upper atmosphere level was longer.