Inversion of Tropospheric Aerosol Extinction Coefficient Profile by Mie-Raman Scattering Lidar

被引:0
|
作者
Shen J. [1 ]
Cao N. [1 ]
机构
[1] School of Atmospheric Physics, Nanjing University of Information Science and Technology, Nanjing, 210044, Jiangsu
来源
Zhongguo Jiguang/Chinese Journal of Lasers | 2017年 / 44卷 / 06期
关键词
Aerosol; Atmospheric optics; Extinction coefficient; Mie scattering; Raman scattering; Wavelet denoising;
D O I
10.3788/CJL201744.0610003
中图分类号
学科分类号
摘要
An observation experiment of atmospheric aerosol based on Mie-Raman scattering lidar in northern suburb of Nanjing is introduced. A soft and hard threshold method is used to deal with Raman scattering lidar's echo signal with wavelet analysis, and different thresholds and different wavelet functions are selected to process the Raman scattering lidar's echo signal. Smoothed Raman scattering lidar's echo signal is obtained. Upper tropospheric atmospheric aerosol extinction coefficient profiles are inversed based on Raman scattering lidar principle. With the Fernald method and the Mie scattering lidar's observation data of aerosol, the atmospheric aerosol extinction coefficient profile in low tropospheric can be obtained. There are three receiving channels in the experimental observation system, including Rayleigh, Mie and Raman scattering channels. The data observed in Mie and Raman scattering channels are mainly studied. Raman scattering lidar's aerosol observational data on 2011-12-08 in northern suburb of Nanjing is processed by four different thresholds. Appropriate threshold is selected to denoise the experimental observed data, and we use the formula of the inversion principle and combine with the distance correction signal to inverse the observed data, and the extinction coefficient profiles of the upper tropospheric atmospheric aerosol are obtained. The aerosol extinction coefficient profiles of low troposphere atmospheric aerosol can be retrieved based on one of the aerosol extinction coefficients of upper tropospheric atmospheric aerosol. After the Mie-Raman scattering lidar joint inversion of tropospheric aerosol extinction coefficient profile, we can clearly find the distributions of aerosol characteristics. The maximum value of aerosol extinction coefficient of low tropospheric free atmosphere is generally about 0.1 km-1, and it shows that free atmospheric of low tropospheric is relatively clean. The aerosol extinction coefficient of upper tropospheric can reach 6 km-1 under the influence of the cloud, and the maximum value of aerosol extinction coefficient is about 0.1 km-1 when there is no cloud. The result shows that the upper atmosphere is relatively clean. © 2017, Chinese Lasers Press. All right reserved.
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