Application of FTIR Spectra Fitting Method in Retrieving Gas Concentrations
ZHU Jun1，2, LIU Wen-qing1, LIU Jian-guo1, GAO Min-guang1, ZHAO Xue-song1, ZHANG Tian-shu1, XU Liang1
1. Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China 2. Institute of Electronic Science and Technology, Anhui University, Hefei 230039, China
Abstract：The method of retrieving gas concentrations by FTIR spectra measurement system is studied. NLLS fitting algorithm is used to complete the quantitative analysis of CO gas under WINDOWS operating system. The spectra of HITRAN database is employed as calibrating and training sets during the procedure of fitting FTIR spectrum. The measured IR transmittance spectra of CO are best fitted with the calculated spectra in HITRAN. The CO concentrations are acquired after the best fitting. The absolute accuracy of the results of retrieve achieves 1%-5%.
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