基于激光外差探测的大气N_(2)O吸收光谱测量与廓线反演  

Measurement and profile inversion of atmospheric N_(2)O absorption spectrum based on laser heterodyne detection

作　　者：薛正跃 李竣 刘笑海 王晶晶 高晓明 谈图 Xue Zheng-Yue;Li Jun;Liu Xiao-Hai;Wang Jing-Jing;Gao Xiao-Ming;Tan Tu(School of Environmental Science and Optoelectronic Technology,University of Science and Technology of China,Hefei 230031,China;Anhui Institute of Optics and Fine Mechanics,Hefei Institute of Material Science,Chinese Academy of Sciences,Hefei 230031,China)

机构地区：[1]中国科学技术大学环境科学与光电技术学院,合肥230031 [2]中国科学院合肥物质科学研究院安徽光学精密机械研究所,合肥230031

出　　处：《物理学报》2021年第21期290-298,共9页Acta Physica Sinica

基　　金：国家自然科学基金重点项目(批准号:41730103);国家自然科学基金青年基金(批准号:41805018);国家重点研发计划(批准号:2017YFC0209705)资助的课题。

摘　　要：激光外差光谱探测由于其光谱分辨率高、体积小、重量轻等优点近年来得到了快速的发展,可用于大气温室气体垂直廓线测量和碳卫星地面定标等.本文报道了利用3.939μm带间级联激光器作为本振光源的测量大气N_(2)O的激光外差系统,自制高精度太阳跟踪仪收集太阳光作为激光外差的信号光源,其跟踪精度达到7 arcsec,激光外差系统的光谱分辨率达到0.004 cm^(–1),测量了合肥地区(31.902°N,117.167°E)大气N_(2)O吸收光谱,得到2838.336和2539.344 cm^(–1)两个强吸收峰,并对吸收信号进行波长标定,得到了N_(2)O分子的整层大气透过率谱,信噪比为93.将高分辨率光谱数据进行归一化处理和频率校正,利用参考正向模型和最优估计算法得到N_(2)O大气整层浓度廓线,标准偏差体积分数为0.000031×10^(–6)—0.0026×10^(–6),对应相对误差范围为0.009%—0.83%.研究结果表明,所搭建的激光外差系统能够实现对大气中N_(2)O的吸收光谱测量以及对N2O的廓线反演,为长期观测大气N_(2)O浓度提供保证.aser heterodyne spectroscopy detection has rapidly developed in recent years due to its high spectral resolution,small size,and light weight.It can be used to measure the atmospheric greenhouse gas vertical profile and calibrate the carbon satellite ground.This paper reports a laser heterodyne system for measuring atmospheric N_(2)O,with a 3.939-μm interband cascade laser used as a local oscillator light source.A homemade high-precision solar tracker collects sunlight as a laser heterodyne signal source.The tracking accuracy reaches 7 arcsec,and the spectral resolution of the laser heterodyne system arrives at 0.004 cm^(–1).The atmospheric N_(2)O absorption spectrum in Hefei area(31.902°N,117.167°E)is measured,and two strong absorption peaks respectively at 288.336 and 2539.344 cm^(–1) are obtained.In addition,the wavelength calibration of the absorption signal,and the entire atmospheric transmittance spectrum of N_(2)O molecules are obtained,and the signal-to-noise ratio is 93.The high-resolution spectrum data are normalized and frequency is corrected,and the N_(2)O atmospheric concentration profile is obtained by using the reference forward model and the optimal estimation algorithm.The standard deviation of volume fraction is in a range of 0.000031—0.0026 ppm,and the corresponding relative error range is 0.009%—0.83%.The research results show that the laser heterodyne system built in this work can be used to measure the absorption spectrum of N_(2)O in the atmosphere and realize the inversion of the N_(2)O profile,which provides a guarantee for long-term observation of atmospheric N_(2)O concentration.

关 键 词：激光外差 透过率光谱 氧化亚氮(N_(2)O) 反演计算 

分 类 号：X16[环境科学与工程—环境科学]