The Thermophysical Properties of the Bagnold Dunes, Mars: Ground-truthing Orbital Data

Status Report From: e-Print archive
Posted: Wednesday, November 29, 2017

Christopher S. Edwards, Sylvain Piqueux, Victoria E. Hamilton, Robin L. Fergason, Ken E. Herkenhoff, Ashwin R. Vasavada, Kristen A. Bennett, Leah Sacks, Kevin Lewis, Michael D. Smith
(Submitted on 29 Nov 2017)

In this work, we compare the thermophysical properties and particle sizes derived from the Mars Science Laboratory (MSL) rover's Ground Temperature Sensor (GTS) of the Bagnold dunes, specifically Namib dune, to those derived orbitally from Thermal Emission Imaging System (THEMIS), ultimately linking these measurements to ground-truth particle sizes determined from Mars Hand Lens Imager (MAHLI) images. In general, we find that all three datasets report consistent particle sizes for the Bagnold dunes (~110-350 microns, and are within measurement and model uncertainties), indicating that particle sizes of homogeneous materials determined from orbit are reliable. Furthermore, we examine the effects of two physical characteristics that could influence the modeled thermal inertia and particle sizes, including: 1) fine-scale (cm-m scale) ripples, and 2) thin layering of indurated/armored materials. To first order, we find small scale ripples and thin (approximately centimeter scale) layers do not significantly affect the determination of bulk thermal inertia from orbital thermal data determined from a single nighttime temperature. Modeling of a layer of coarse or indurated material reveals that a thin layer (< ~5 mm; similar to what was observed by the Curiosity rover) would not significantly change the observed thermal properties of the surface and would be dominated by the properties of the underlying material. Thermal inertia and grain sizes of relatively homogeneous materials derived from nighttime orbital data should be considered as reliable, as long as there are not significant sub-pixel anisothermality effects (e.g. lateral mixing of multiple thermophysically distinct materials).

Comments:    submitted to the Journal of Geophysical Research: Planets
Subjects:    Earth and Planetary Astrophysics (astro-ph.EP)
Cite as:    arXiv:1711.10699 [astro-ph.EP] (or arXiv:1711.10699v1 [astro-ph.EP] for this version)
Submission history
From: Christopher Edwards
[v1] Wed, 29 Nov 2017 06:35:13 GMT (1794kb)

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