Abstract
Over the last 16 years, the Mars Climate Sounder (MCS) onboard the Mars Reconnaissance Orbiter (MRO) has acquired a large body of surface observations at visible and thermal infrared wavelengths. Primary differentiators between the MCS record and other surface datasets include mission duration, regular global coverage, and high emission angles associated with most observations. These data have been analyzed to generate a global median apparent thermal inertia map that smooths out artificial spatial variability (i.e., streaking along orbital ground tracks) common in other maps. At mid and low latitudes, high emission angle observations yield similar nighttime thermal inertia values compared to nadir observations, even if grazing angles should favor vertically rough materials oriented towards MCS (i.e., material poking out of the ground, presumably associated with high thermal inertia rocks and scarps). This result independently confirms that fines control the Martian thermal inertia, not rocks, and also suggests that most rock and bedrock exposures should be characterized by low aspect ratios (i.e., appear platy or flat, regardless of subsurface shape). Selected global temperature maps are also presented. They show the influence of polar processes, the latitudinal distribution of exposed ices, and physical properties of the Martian regolith on surface temperatures. Temperature controls at regional and global scales include the variation of insolation with season and latitude, atmospheric composition, global circulation, the presence of snow precipitations, and various regolith properties (i.e., albedo and thermal inertia).
Published Version
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