Standard terrestrial atmospheric transmission (thick black line, also shown in Figs. 1 and 2) compared with our retrieved transmission function applicable for the EXES data of Mars. Our transmission curve was inferred from the best fit between the observed spectrum of Mars (after removal of the offset due to scattered light) and the product of the nominal synthetic model of Mars by the transmission function (see Fig. 5). The terrestrial atmospheric transmission is zero in the core of the strong water line at 1387.5 cm^-1.