Retrieval of the aerosol extinction coefficient of 1064nm based on high-spectral-resolution lidar

•Calculating and analysing the different biases of Ta for delicately correcting extinction coefficient.•Using threshold correction method to correct the error caused by the derivation of Ta, and the remaining extinction coefficient is interpolated after threshold correction.•A dual-channel FPE is de...

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Veröffentlicht in:Journal of quantitative spectroscopy & radiative transfer 2020-11, Vol.256, p.107298, Article 107298
Hauptverfasser: Li, Siwen, Di, Huige, Wang, Qiyu, Han, Geng, Hua, Dengxin, Li, Yan
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Sprache:eng
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Zusammenfassung:•Calculating and analysing the different biases of Ta for delicately correcting extinction coefficient.•Using threshold correction method to correct the error caused by the derivation of Ta, and the remaining extinction coefficient is interpolated after threshold correction.•A dual-channel FPE is designed and used to extract aerosol Mie scattering signal and suppress Cabannes–Brillouin scattering in NHSRL.•The extinction coefficient profiles of three cases of severe haze day, moderate haze day and mild haze day were detected and retrieved by the NHSRL. It is difficult to independently obtain aerosol optical parameters at the near-infrared wavelength using lidar. A new high-spectral-resolution technology is proposed to obtain the aerosol extinction coefficient profile at 1064 nm. The high-spectral-resolution detection method by extracting Mie scattering and suppressing Cabannes–Brillouin scattering is applied in the lidar at 1064 nm to improve the detection signal-to-noise ratio. The system parameters of near-infrared high-spectral-resolution LiDAR (NHSRL) must be calibrated in this method; then, the optical parameters are accurately deduced. The effect of the system parameters (transmittances of the spectral filter for molecule and aerosol) on the detection results in this method is discussed and analysed. The transmittance of the spectral filter for aerosol scattering is a key parameter in the retrieval of the extinction coefficient, and the sensitivity of the inversion results to the transmittance is analysed and discussed. The method to distinguish the large deviation data of the extinction coefficient is discussed and provided, and the third derivative of the optical thickness profile is adopted to determine the data. According to the characteristics of the inversion signal, the method to correct the extinction coefficient profile is also presented. The correction algorithm can obviously increase the inversion accuracy of the extinction coefficient. The 1064-nm NHSRL Lidar was developed at Xi'an University of Technology. A dual-channel Fabry-Perot Etalon was designed and used to extract the aerosol Mie scattering signal and suppress Cabannes–Brillouin scattering in this NHSRL. The NHSRL lidar observations were performed, and extinction coefficient profiles at 1064 nm were obtained. The results demonstrate that the method can obtain an accurate profile of the extinction coefficients.
ISSN:0022-4073
1879-1352
DOI:10.1016/j.jqsrt.2020.107298