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

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

Research output: Contribution to journalArticlepeer-review

34 Scopus citations


We compare the thermophysical properties and particle sizes derived from the Mars Science Laboratory rover's Ground Temperature Sensor of the Bagnold dunes, specifically Namib dune, to those derived orbitally from Thermal Emission Imaging System, ultimately linking these measurements to ground truth particle sizes determined from Mars Hand Lens Imager images. In general, we find that all three datasets report consistent particle sizes for the Bagnold dunes (~110–350 μm and are within measurement and model uncertainties), indicating that particle sizes of homogeneous materials inferred from temperature measurements and thermophysical models 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 (centimeter to meter scale) ripples and (2) thin layering of indurated/armored materials. To first order, we find that small-scale ripples and thin (approximately centimeter scale) layers do not significantly affect the determination of bulk thermal inertia from orbital thermal data using 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 particle sizes of relatively homogeneous materials derived from nighttime orbital data should be considered as reliable, as long as there are no significant subpixel anisothermality effects (e.g., lateral mixing of multiple thermophysically distinct materials).

Original languageEnglish (US)
Pages (from-to)1307-1326
Number of pages20
JournalJournal of Geophysical Research: Planets
Issue number5
StatePublished - May 2018


  • Bagnold dunes
  • Mars Science Laboratory
  • Thermal Emission Imaging System
  • particle size
  • thermal inertia

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science


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