Ground-based remote sensing of atmospheric total column CO2 and CH4 by direct sunlight in Hefei

Fourier transform spectrometry has played an important role in the three-dimensional greenhouse gas monitoring as the focus of attention on global warming in the past few years. In this paper, a ground-based low-resolution remote sensing system measuring the total columns of CO2 and CH4 is developed...

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Published in中国物理B:英文版 no. 12; pp. 563 - 569
Main Author 程巳阳 徐亮 高闽光 李胜 金岭 童晶晶 魏秀丽 刘建国 刘文清
Format Journal Article
LanguageEnglish
Published 01.12.2013
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ISSN1674-1056
2058-3834
DOI10.1088/1674-1056/22/12/129201

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Summary:Fourier transform spectrometry has played an important role in the three-dimensional greenhouse gas monitoring as the focus of attention on global warming in the past few years. In this paper, a ground-based low-resolution remote sensing system measuring the total columns of CO2 and CH4 is developed, which tracks the sun automatically and records the spectra in real-time and has the advantages of portability and low cost. A spectral inversion algorithm based on nonlinear least squares spectral fitting procedure for determining the column concentrations of these species is described. Atmospheric transmittance spectra are computed line-by-line in the forward model and observed on-line by direct solar radiation. Also, the wavelength shifts are introduced and the influence of spectral resolution is discussed. Based on this system and algorithm, the vertical columns of O2, CO2, and CH4 are calculated from total atmospheric observation transmittance spectra in Hefei, and the results show that the column averaged dry-air mole fractions of CO2 and CH4 are measured with accuracies of 3.7% and 5%, respectively. Finally, the H2O columns are compared with the results observed by solar radiometer at the same site and the calculated correlation coefficient is 0.92, which proves that this system is suitable for field campaigns and used to monitor the local greenhouse gas sources under the condition of higher accuracy, indirectly.
Bibliography:Cheng Si-Yang, Xu Liang, Gao Min-Guang, Li Sheng, Jin Ling, Tong Jing-Jing, Wei Xiu-Li, Liu Jian-Guo, Liu Wen-Qing (Key Laboratory of Environment Optics & Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China)
Fourier transform spectrometry has played an important role in the three-dimensional greenhouse gas monitoring as the focus of attention on global warming in the past few years. In this paper, a ground-based low-resolution remote sensing system measuring the total columns of CO2 and CH4 is developed, which tracks the sun automatically and records the spectra in real-time and has the advantages of portability and low cost. A spectral inversion algorithm based on nonlinear least squares spectral fitting procedure for determining the column concentrations of these species is described. Atmospheric transmittance spectra are computed line-by-line in the forward model and observed on-line by direct solar radiation. Also, the wavelength shifts are introduced and the influence of spectral resolution is discussed. Based on this system and algorithm, the vertical columns of O2, CO2, and CH4 are calculated from total atmospheric observation transmittance spectra in Hefei, and the results show that the column averaged dry-air mole fractions of CO2 and CH4 are measured with accuracies of 3.7% and 5%, respectively. Finally, the H2O columns are compared with the results observed by solar radiometer at the same site and the calculated correlation coefficient is 0.92, which proves that this system is suitable for field campaigns and used to monitor the local greenhouse gas sources under the condition of higher accuracy, indirectly.
11-5639/O4
carbon dioxide methane ground-based remote sensing solar absorption spectroscopy
ISSN:1674-1056
2058-3834
DOI:10.1088/1674-1056/22/12/129201