Fig. 1. Flow of constructing atmospheric contour background library

Fig. 2. Absorption spectra and Absorption cross section of methane and its interfering components in the 1 200~1 400 cm^-1 band range

Fig. 3. Measured and RFM-simulated irradiance of HIRAS in the 1 200~1 400 cm^-1 band

Fig. 4. Spectra of CH₄ at different concentration variations

Fig. 5. Changes in brightness temperature induced by changes in different concentrations of CH₄

Fig. 6. Changes in irradiance due to changes in each interference component

Fig. 7. Changes in brightness temperature due to changes in each interference component

Fig. 8. Methane inversion channel selection results

Fig. 9. Methane inversion channel informativeness