激光与光电子学进展, 2018, 55 (11): 110102, 网络出版: 2019-08-14
Rayleigh-Raman-Mie激光雷达探测南京北郊对流层气溶胶光学特性 下载: 1084次
Detection of Tropospheric Aerosol Optical Properties by Rayleigh- Raman-Mie Lidar in the Northern Suburb of Nanjing
大气光学 气溶胶 消光系数 后向散射系数 激光雷达比 小波去噪 atmospheric optics aerosol extinction coefficient backscattering coefficient lidar ratio wavelet denoising
摘要
利用中国气象局南京综合观测基地的Rayleigh-Raman-Mie激光雷达,对南京北郊对流层气溶胶进行观测分析。通过软阈值滤波的小波去噪方法对波长为607 nm的Raman回波信号进行平滑,利用激光雷达Raman通道的实验数据反演对流层高空的气溶胶消光系数,结合波长为532 nm的Mie散射信号反演对流层高空气溶胶后向散射系数和激光雷达比。实验结果表明:软阈值滤波的小波去噪方法可以很好地去除噪声信号,提高反演结果的准确性;在晴空的天气条件下,南京北郊高空气溶胶消光系数的变化范围为0.03~0.07 km
-1,后向散射系数变化范围为0.011~0.024 km
-1·sr
-1,激光雷达比的变化范围为22~52 sr,表明南京北郊高空存在一定含量的气溶胶;实验期间测多次测得卷云,卷云的激光雷达比为17 sr±10 sr。
Abstract
The tropospheric aerosols in the northern suburb of Nanjing is observed and analyzed with the Rayleigh-Raman-Mie lidar in Nanjing comprehensive observation base of the China Meteorological Administration. The Raman scattering signals with the wavelength of 607 nm are smoothed by the wavelet denoising method on the basis of soft threshold filtering. The extinction coefficient of upper tropospheric aerosols is retrieved based on the data from Raman channel of the lidar. The backscattering coefficient and the lidar ratio of upper tropospheric aerosols are retrieved with the Mie scattering signal with the wavelength of 532 nm. The experimental results show that the wavelet denoising method on the basis of soft threshold filtering can remove the signal noise well and improve the accuracy of the retrieval results. In sunny and cloud-free day, the extinction coefficient of upper tropospheric aerosols is from 0.03 km
-1 to 0.07 km
-1, the aerosol backscattering coefficient is from 0.011 km
-1·sr
-1 to 0.024 km
-1·sr
-1, and the lidar ratio is from 22 sr to 52 sr. It is indicated that there are still some aerosol particles in upper tropospheric of the northern suburb of Nanjing. Cirrus clouds have been measured many times during the experiment. The lidar ratio cirrus clouds is 17 sr±10 sr.
虞历尧, 曹念文, 沈吉. Rayleigh-Raman-Mie激光雷达探测南京北郊对流层气溶胶光学特性[J]. 激光与光电子学进展, 2018, 55(11): 110102. Liyao Yu, Nianwen Cao, Ji Shen. Detection of Tropospheric Aerosol Optical Properties by Rayleigh- Raman-Mie Lidar in the Northern Suburb of Nanjing[J]. Laser & Optoelectronics Progress, 2018, 55(11): 110102.