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介绍了基于米-拉曼散射激光雷达的南京北郊大气气溶胶观测实验,采用小波分析中的软硬阈值方式处理拉曼散射激光雷达回波信号,选取不同的阈值和不同的小波函数处理拉曼散射激光雷达回波信号,得到了平滑的拉曼散射激光雷达信号。根据拉曼散射激光雷达原理反演对流层高空大气气溶胶消光系数廓线,借助弗纳尔德方法并利用米散射激光雷达气溶胶观测数据,反演得到对流层低空大气气溶胶消光系数廓线。实验观测系统中有瑞利、米散射和拉曼散射3个接收通道,重点研究了米散射和拉曼散射通道接收到的观测数据,对南京北郊2011-12-08晚间拉曼散射激光雷达的气溶胶观测数据进行4种不同阈值处理。选择合适的阈值对实验观测数据进行去噪,然后利用反演原理公式并结合距离矫正信号对观测数据进行反演,得到对流层高空大气气溶胶消光系数廓线;利用其中一处的气溶胶消光系数可以反演得到对流层低空大气气溶胶消光系数廓线。利用米-拉曼散射激光雷达联合反演对流层气溶胶消光系数廓线,可以清晰看出气溶胶的分布特征,对流层低空自由大气的气溶胶消光系数最大值一般为0.1km~(-1)左右,表明对流层低空自由大气比较干净;对流层高空大气气溶胶消光系数在云影响下可达到6km~(-1),无云时气溶胶消光系数最大值一般为0.1km~(-1)左右,表明高空大气比较干净。
Atmospheric aerosol observations in the northern suburb of Nanjing are described based on the M - Raman scattering lidar. The hard and soft thresholding methods in wavelet analysis are used to deal with Raman scattering lidar echo signals. Different thresholds and different wavelet functions Man scattering laser radar echo signals, get a smooth Raman scattering lidar signal. Based on the Raman scattering lidar principle, the tropospheric aerosol extinction coefficient profile was retrieved and the aerosol extinction coefficient profile of the tropospheric low-altitude aerosol was retrieved by means of the Vernal method and using the data of the LASAR aerosol. In the experimental observation system, Rayleigh, rice scattering and Raman scattering receive three channels, focusing on the rice scattering and Raman scattering channel received observations, the northern suburb of Nanjing December 12, 2011 Evening Raman scattering lidar Aerosol observations of 4 different thresholds. Select the appropriate threshold to denoise the experimental observation data, and then use the inversion principle formula and the distance correction signal to invert the observed data to get the aerosol extinction coefficient profile of the upper troposphere; use one of the aerosol extinction coefficient The tropospheric aerosol extinction coefficient profiles can be derived inversely. The distribution characteristics of aerosols can be clearly seen using the Michelson-Raman scattering Lidar backscattering profile. The maximum aerosol extinction coefficient of the free atmosphere in the lower troposphere is about 0.1km -1, Which indicates that the free atmosphere in the lower troposphere is relatively clean. The atmospheric aerosol extinction coefficient of the upper troposphere can reach 6km -1 under the influence of cloud, and the maximum aerosol extinction coefficient when cloudless is about 0.1km -1, The atmosphere is clean.