气溶胶光学特性对宽谱差分吸收激光雷达NO_(2)质量浓度反演结果的影响  

Influence of Aerosol Optical Properties on Retrieval Results of NO2 Mass Concentration in Broadband Differential Absorption Lidar

作　　者：成远 余纪恒 宫振峰 梅亮 Cheng Yuan;Yu Jiheng;Gong Zhenfeng;Mei Liang(School of Optoelectronic Engineering and Instrumentation Science,Dalian University of Technology,Dalian 116024,Liaoning,China)

机构地区：[1]大连理工大学光电工程与仪器科学学院,辽宁大连116024

出　　处：《光学学报》2024年第6期175-187,共13页Acta Optica Sinica

基　　金：国家自然科学基金(62075025)。

摘　　要：针对宽谱连续波差分吸收激光雷达(DIAL)的特点,通过仿真不同大气条件下的激光雷达信号,计算分析宽谱DIAL气溶胶消光和后向散射效应引起的二氧化氮(NO_(2))质量浓度反演误差。研究结果表明:当大气气溶胶均匀分布时,NO_(2)质量浓度反演误差主要取决于气溶胶消光效应,而后向散射效应引起的NO_(2)质量浓度反演误差一般可忽略不计;当大气气溶胶非均匀分布时,气溶胶后向散射效应引起的NO_(2)质量浓度反演误差依赖于气溶胶非均匀分布程度,且与波长指数成反比。此外,适当增大分段拟合距离可有效降低气溶胶后向散射效应引起的NO_(2)质量浓度反演误差。利用光谱近似得到宽谱NO_(2)-DIAL气溶胶消光和后向散射效应引起的NO_(2)质量浓度反演误差的近似模型,通过对比模拟计算的结果,验证了近似模型评估NO_(2)质量浓度反演误差的可行性。Objective Accurate monitoring of nitrogen dioxide(NO_(2)),a significant atmospheric pollutant,is essential for effective environmental management.Differential absorption lidar(DIAL)technology has emerged as a robust approach to address this challenge.However,the wavelength dependency of aerosol optical properties has a substantial impact on NO_(2)-DIAL measurements.Previous studies mostly focus on the narrow-band NO_(2)-DIAL technique without considering the spectral width of the emitted laser pulse.Therefore,the influence of aerosol optical properties on the retrieved NO_(2) mass concentration of the broad-band DIAL technique remains unclear.We aim to investigate aerosol-induced NO_(2) mass concentration errors under various atmospheric conditions through simulation studies and an approximation method for the broadband NO_(2)-DIAL technique.We hope that this research can offer valuable insights into comprehending the influence of aerosol optical properties on broadband NO_(2)-DIAL techniques.Methods We carry out research based on the broadband NO_(2)-DIAL technique(Fig.1)employing the Scheimpflug principle.The broadband NO_(2)-DIAL system utilizes image sensors as detectors and high-power laser diodes as light sources(wavelength is 450 nm,power is 1.6 W),with an emission spectral typically ranging from 1-2 nm(full width at half maximum).Two different methods(the simulation method and the approximation method)have been adopted to elucidate the influence of atmospheric aerosols on the broadband NO_(2)-DIAL technique.The broadband DIAL equation has been established,based on which simulated atmospheric lidar signals can be obtained with measured laser spectra and different atmospheric parameters,e.g.,aerosol extinction coefficient,backscattering coefficient andÅngström exponent(Fig.5).Therefore,the NO_(2) mass concentration containing the aerosol-induced retrieval errors can be acquired through segmented fitting for the simulated atmospheric lidar signals(Fig.6).As a result,the NO_(2) mass concentration errors int

关 键 词：大气光学 宽谱差分吸收激光雷达 沙氏成像原理 二氧化氮 气溶胶光学特性 

分 类 号：O436[机械工程—光学工程]