Atmospheric and surface properties of Mars obtained by infrared spectroscopy on Mariner 9

Abstract

During the almost 1‐year operational lifetime of Mariner 9 the infrared spectroscopy experiment obtained data over a large portion of Mars. Between June and October 1972, improvements were made in the CO2 transmittances, which are necessary for the interpretation of the thermal emission spectra. Recently obtained spectra indicate that strong seasonal variations in the water vapor distribution occurred over both polar regions. The wettest atmospheric conditions observed so far contain 20–30 precipitable μm of water over the north polar cap during northern spring. A low‐resolution pressure map is presented that covers that portion of the planet between latitudes −60° and +25°. A more detailed study of the Coprates canyon indicates that, at its lowest point, the canyon floor must be at least 5km below the rim. Applications of tidal theory to temperature fields derived from the spectra indicate diurnal surface pressure fluctuations of as much as 12% during the Great Dust Storm of 1971–1972. Arguments based on radiative transfer calculations for model dust clouds composed of spherical quartz particles suggest that particle radii during the storm were on the order of a few micrometers; a complete specification of particle parameters must await the development of more refined models.

The Modern Near-Surface Martian Climate: A Review of In-situ Meteorological Data from Viking to Curiosity

“…Seasonal water reservoirs include water ice on or within the seasonal or residual polar caps, surface or subsurface ice in high-latitude regions, physically adsorbed and chemically-bound water within the near-surface regolith, and possibly surface and subsurface liquid water in the form of liquid saline solutions (brine) (Jakosky 1985). Satellite and telescopic observations of variations in the integrated H 2 O column abundance (Conrath et al 1973;Jakosky and Farmer 1982;Sprague et al 1996;Smith 2004;Fedorova et al 2006;Fouchet et al 2007;Melchiorri et al 2006), in combination with numerical modeling, have been used to determine the relative importance of the various processes controlling the seasonal H 2 O cycle (Flasar and Goody 1976;Jakosky and Farmer 1982;Haberle and Jakosky 1990;Richardson and Wilson 2002;Böttger et al 2005). The seasonal H 2 O cycle is important for the Martian climate because it leads to the formation and affects the stability of water ice deposits on the surface and of water ice clouds in the atmosphere (Jakosky and Haberle 1992;Richardson and Wilson 2002;Smith et al 1997;Haberle et al 1999;Montmessin et al 2004;Madeleine et al 2012).…”

The relationship between MOLA northern hemisphere topography and the 6.1‐Mbar atmospheric pressure surface of Mars

“…Because initial determinations of the large-scale topography of Mars were based on atmospheric pressure measurements [Conrath et al, 1973 [Smith eta!., 1998a]. These data are significantly more precise than previous observations of Mars topography and provide the impetus to re-define the position of the 6. l-mbar pressure surface to assist in atmospheric studies and in targeting future Mars landers.…”

Martian atmospheric Lee waves

“…The thermal structure was obtained for extensive, though not complete, coverage in local time and latitude in the earlier part of the mission and for somewhat less extensive coverage in the latter part of the mission (Hanel, et al, 1972;Conrath, et al , 1973). The dynamical nature of the atmosphere can be investigated using the thermal structure or can be inferred from apparent cloud motions (Briggs and Leovy, 1974).…”