Thick black line: TEXES spectrum of Mars near the HDO line in the vicinity of 1237.08 cm^-1, integrated over Region A (9 pixels), compared with synthetic spectra (March 1, 2014; Ls = 96°). The continuum fluctuation in the TEXES data has been corrected by using the continuum on each side of each line and assuming a straight line between these two points. The airmass is 1.20. Models: H₂O = 375 ppbv (green), 450 ppbv (red), 525 ppbv (blue). The best fit is obtained for HDO = 450 ppbv.