Parameters of CH4 absorption lines broadened by atmospheric air pressure in the 2300 nm region
T.M. Petrova, A.M. Solodov, A.A. Solodov, V.M. Deichuli, T.Yu. Chesnokova
V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, Tomsk, Russia
Keywords: methane, absorption lines, atmospheric transmission, spectroscopic databases
Abstract
Methane is one of key greenhouse gases, whose concentration has been increasing in recent decades. This leads to an increase in the temperature of the Earth's surface. To monitor the methane content in the atmosphere the accurate knowledge of the absorption spectrum of CH4 molecule is required. In this work, the parameters of methane absorption lines broadened by atmospheric air pressure are presented in the spectral region 4345-4360 cm-1. Data were obtained from spectra recorded at a Bruker IFS 125HR Fourier spectrometer with a spectral resolution of 0.005-0.01 cm-1 at room temperature and five values of buffer gas pressure. Atmospheric transmission was simulated using the obtained results and the line parameters from HITRAN and GEISA spectroscopic databases. The comparison with measured atmospheric solar spectra shows that the use of the CH4 absorption line parameters obtained in this work gives the best result in terms of root-mean-square deviation.
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