Sublimation of terrestrial permafrost and the implications for ice-loss processes on Mars

Sublimation of ice is rate-controlled by vapor transport away from its outer surface and may have generated landforms on Mars. In ice-cemented ground (permafrost), the lag of soil particles remaining after ice loss decreases subsequent sublimation. Varying soil-ice ratios lead to differential lag de...

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Bibliographic Details
Published in:Nature communications 2019-04, Vol.10 (1), p.1716-1716, Article 1716
Main Authors: Douglas, Thomas A., Mellon, Michael T.
Format: Article
Language:English
Subjects:
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Convection
Diffusion coefficient
Heat loss
Humanities and Social Sciences
Ice
Landforms
Landing sites
Loess
Manned Mars missions
Mars
Mars exploration
Mars surface
Morphology
multidisciplinary
Permafrost
Science
Science (multidisciplinary)
Soil porosity
Soils
Sublimation
Target recognition
Terrestrial environments
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Summary:Sublimation of ice is rate-controlled by vapor transport away from its outer surface and may have generated landforms on Mars. In ice-cemented ground (permafrost), the lag of soil particles remaining after ice loss decreases subsequent sublimation. Varying soil-ice ratios lead to differential lag development. Here we report 52 years of sublimation measurements from a permafrost tunnel near Fairbanks, Alaska, and constrain models of sublimation, diffusion through porous soil, and lag formation. We derive the first long-term in situ effective diffusion coefficient of ice-free loess, a Mars analog soil, of 9.05 × 10 −6  m 2  s −1 , ~5× larger than past theoretical studies. Exposed ice-wedge sublimation proceeds ~4× faster than predicted from analogy to heat loss by buoyant convection, a theory frequently employed in Mars studies. Our results can be used to map near-surface ice-content differences, identify surface processes controlling landform formation and morphology, and identify target landing sites for human exploration of Mars. Sublimation of ice is believed to have generated a variety of landforms on Mars and other planetary bodies. Here the authors show the first long-term in situ effective diffusion coefficient of terrestrial ice-free loess (Mars analog soil), scaled to Mars average pressure, temperature and CO 2 atmosphere.
ISSN:2041-1723
2041-1723
DOI:10.1038/s41467-019-09410-8