Spectrum of Mars between 1387.8 and 1390.0 cm^-1 (thick black line), integrated over the Martian disk, recorded with EXES (Ls = 113°, normalized radiance). Synthetic models of the Martian atmosphere: contributions from CO₂ (purple), H₂O (300 ppmv, blue), HDO (467 ppbv, green). The EXES spectrum and the models are enlargements of Fig. 1. Thin black line (in absolute units shifted by +0.20): standard transmission from the terrestrial atmosphere computed with the EXES model.