1. Xi’an Institute of Optics and Precision Mechanics of Chinese Academy of Sciences; Key Laboratory of Spectral Imaging Technology of Chinese Academy of Sciences, Xi’an 710119, China 2. Academy of Opto-Electronics of Chinese Academy of Sciences, Key Laboratory of Computational Optical Imaging Technology of Chinese Academy of Sciences, Beijing 100049, China 3. University of Chinese Academy of Sciences, Beijing 100190, China
Abstract：The present paper describes the observations and measurements of the infrared absorption spectra of CO2 on the Earth’s surface with OP/FTIR method by employing a mid-infrared reflecting scanning Fourier transform spectrometry, which are the first results produced by the first prototype in China developed by the team of authors. This reflecting scanning Fourier transform spectrometry works in the spectral range 2 100～3 150 cm-1 with a spectral resolution of 2 cm-1. Method to measure the atmospheric molecules was described and mathematical proof and quantitative algorithms to retrieve molecular concentration were established. The related models were performed both by a direct method based on the Beer-Lambert Law and by a simulating-fitting method based on HITRAN database and the instrument functions. Concentrations of CO2 were retrieved by the two models. The results of observation and modeling analyses indicate that the concentrations have a distribution of 300~370 ppm, and show tendency that going with the variation of the environment they first decrease slowly and then increase rapidly during the observation period, and reached low points in the afternoon and during the sunset. The concentrations with measuring times retrieved by the direct method and by the simulating-fitting method agree with each other very well, with the correlation of all the data is up to 99.79%, and the relative error is no more than 2.00%. The precision for retrieving is relatively high. The results of this paper demonstrate that, in the field of detecting atmospheric compositions, OP/FTIR method performed by the Infrared reflecting scanning Fourier transform spectrometry is a feasible and effective technical approach, and either the direct method or the simulating-fitting method is capable of retrieving concentrations with high precision.
Key words：Infrared spectra of atmospheres;Concentration retrieving;Beer-lambert law;Instrument functions;Reflecting scanning mirror
[1] IPCC, Climate Change 2001: The Scientific Basis. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, New York. 2001. [2] IPCC, Climate Change 2007: The Physical Science Basis, Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, New York. 2007. [3] LI Cui-na（李翠娜）. The Study on Temperature Dependence of the Atmospheric Gases Absorption(大气气体吸收的温度依赖关系研究). Nanjing: Nanjing Unviersity of Information Science & Technology(南京：南京信息工程大学)，2008. [4] CHENG Jie, LIU Qin-huo, LI Xiao-wen(程 洁，柳钦火，李小文). Remote Sensing Information(遥感信息), 2007，2: 90. [5] WU Xiao-li, FAN Dong-dong, WANG Ping(巫晓丽，范东栋，王 平). Spacecraft Recovery & Remote Sensing(航天返回与遥感)，2007，28（2）: 15. [6] TONG Jing-jing, GAO Min-guang, LIU Zhi-ming, et al(童晶晶，高闽光，刘志明，等). Infrared Technology(红外技术), 2010, 32(8)：491. [7] U. S. Environmental Protection Agency. EPA 625R-96/010b, NTIS PB99-172355, Center for Environmental Research Information, Office of Research and Development, Cincinnati, OH, 1999. [8] XU Liang, LIU Jian-guo, GAO Min-guang, et al(徐 亮，刘建国，高闽光，等). Infrared Technology(红外技术), 2007，29（4）：239. [9] Griffiths P R, Hirsche B L, Manning C. Vibrational Spectroscopy, 1999, 19: 165. [10] SU Xing, HUANG Hui-min, XIANGLI Bin(苏 星，黄惠民，相里斌). Acta Photonica Sinica (光子学报), 2001, 30(12)：1474. [11] SHI Guang-yu(石广玉). Atmospheric Radiation(大气辐射学). Beijing: Science Press(北京：科学出版社), 2007. 83, 174. [12] Rothman L S, Gordon I E, Barbe A, et al. J. of Quant. Spectros. &. Radiat. Transf., 2009, 110: 533. [13] DAI Tie, ZHENG You-fei, SHI Guang-yu(戴 铁，郑有飞，石广玉). Meteorological and Environmental Sciences(气象与环境科学)，2008，31(1): 1.
