Mars atmospheric water vapor in the southern hemisphere: MAWD observations revisited Original Research Article

Recent retrievals of Mars atmospheric water vapor from TES data show remarkable disagreement with Viking MAWD observations. Major differences in column water abundance are observed at perihelion near the South Pole. MAWD data do not exceed 10 pr-μm in this region, and have a maximum water abundance in Hellas. TES data and modeling results indicate quantities as high as 30 pr-μm near the South Pole. We show that MAWD data are substantially affected by aerosol multiple scattering due to circumpolar and global dust storms, especially in the polar region where the airmass factor is highest. We considered the influence of aerosols on 1.38 μm water vapor band under various observational geometries and find that much higher abundances of water vapor can be retrieved from the MAWD data, which is consistent with TES results. We also have corrected the Southern Summer MAWD data for aerosol scattering and analyzed the resulting zonal structure.