在拉曼(Raman)激光雷达探测CO2实验中所采集的拉曼回波信号具有比较大的统计误差,有效减小统计误差,获得较高的探测精度是非常重要的工作。利用自适应滤波器对拉曼回波信号分段进行数据处理,可得到在分段的各个空间间隔内的随距离几乎不变的CO2混合比统计误差,经过自适应滤波器对信号进行处理后,Raman激光雷达对合肥地区夜晚CO2气体浓度探测达到比较高的测量精度,在1.5-5 km高度范围内,CO2浓度统计误差最大为2.5%,5-8 km统计误差最大为5%,8-10 km统计误差最大为10%。利用此技术也可以量化估计在较高的空间分辨率下满足探测精度要求的激光脉冲数。

It is important to decrease the statistical error for improving the measurement precision of Raman lidar for the large statistical error of the Raman backscattering signals. An adaptive filter signal processing technique is applied to the Raman lidar for atmospheric CO2 measurement by subsection,and the result of the statistical error of the atmospheric CO2 mixing ratio changes little with detecting range in each subsection. After signal processing by the technique,we obtained the high precision of Raman lidar measurement of atmospheric CO2 concentration at night in Hefei. The maximum statistical error of atmospheric CO2 concentration was 2.5% from 1.5 to 5 km,5% form 5 to 8 km,and 10% from 8 to 10 km. The technique also can be used to determine the number of laser shots necessary for a desired statistical accuracy and spatial resolution.