LM以及CIA效应对TanSat 3个波段吸收光谱的影响

Influence of LM and CIA on the Absorption Spectral in the Three Bands of TanSat

分析了Line Mixing(LM)以及Collision-Induced Absorption(CIA)效应对中国全球二氧化碳监测科学实验卫星(TanSat)反演CO2所用的CO2的1.61、2.06μm以及O20.76μm 3个波段气体吸收的影响。LM效应对CO2的1.61、2.06μm气体吸收截面的影响约2%,LM以及CIA效应对O20.76μm波段的影响,在翼部达到75%,在中心区域约2%。LM效应使谱线线型变窄,使谱线中心吸收波数处吸收截面增大,翼部区域吸收截面减小。考虑LM以及CIA效应后,减小采用传统Voigt线型计算截面存在的结构性误差。分析了气体吸收截面以及LM效应随温度、气压的变化情况,LM效应在压强较大以及温度较低时对吸收截面影响较大。最后,在3个波段选择合理的气压、温度以及波数间隔,建立三维吸收截面查找表,在满足计算精度的同时节约时间,满足卫星大量观测反演的需要。

This paper analyses the Line Mixing (LM) and Collision-Induced Absorption (CIA) effect on the absorption in the 1.61,2.06 and 0.76 μm regions which used in the TanSat for retrieval of CO2.The LM effect on the cross section in 1.61 and 2.06 μm is about 2％.At the same time,analysing the LM and CIA effect on the absorption cross section in the 0.76 μm of O2.The relative effect of LM and CIA can reach 75％ in the wings and about 2％ at the P and R branch peaks.LM narrows the profile,leads to dips in the wings and to peaks in the centers to reduce the structural error by Voigt profile.This study analyses the change of absorption cross section and LM effect according to pressure and temperature,the LM effect is more significant with the greater pressure and the lower temperature.In the three bands,we chose the reasonable pressure,temperature and wavenumber interval to build the absorption cross section lookup table in advance to satisfy retrieval data throughput.