Using Different Spectroscopic Databases to Model the Transfer of Radiation in the Near-IR Range and Retrieve the Content of Methane in the Atmosphere

Atmospheric solar spectra in the absorption lines of methane in the near-IR range are modeled and compared using spectra measured on a ground-based Fourier transform spectrometer with high spectral resolution under different atmospheric conditions. The content of methane in the atmospheric column is retrieved using different versions of spectroscopic databases HITRAN (2008, 2012, 2016, 2020), GEISA (2015, 2020), and ATM (2016, 2020) and the CH₄ line list GOSAT2014. The RMS value averaged over 1346 spectra (the deviation of the calculated spectra from ones measured) is calculated for each spectroscopic base. The lowest RMS value is observed for results obtained with CH₄ absorption lines from ATM2020, ATM2016, and HITRAN2008. Parameters of the CH₄ absorption lines that introduce the greatest error into modeling radiative transfer in the atmosphere are revealed in the spectral range of 6000–6100 cm^–1.