Spectrum of Mars between 1388.10 and 1388.35 cm^-1 (thick black line), integrated over the Martian disk, recorded with EXES (Ls = 113°, normalized radiance). Synthetic models of the Martian atmosphere with the CO₂ contribution for a FWHM value of 0.028 cm^-1 with a Gaussian profile (green), a FWHM of 0.024 cm^-1 with a Gaussian profile (red) and a FWHM of 0.024 cm^-1 with a sinc² profile (blue). The two profiles with FWHM = 0.024 cm^-1 are almost identical. The FWHM of 0.024 cm^-1 with a Gaussian shape is adopted in our analysis.