Knowledge Bank

Recent studies, using laboratory and atmospheric spectra, have demonstrated the influence of line-mixing effects on $CH4$ infrared absorption. This phenomenon can significantly affect remote sensing results for atmospheric applications and the contribution of $CH4$ to the green house effect. We propose a model of the relaxation operator in order to account for these effects in the computations of the absorption. The model was built using a semi-classical calculation of collisional energy transfer $ratesa$ and few empirical parameters. Results obtained for $N2$-broadened spectra of the $\nu 3$ band of $CH4$ (near $3\mu$m) including laboratory measurements covering different pressure and temperature ranges, and atmospheric spectra will be presented.