A Reappraisal of Near-Tropical Ice Stability on Mars

By Keith Cowing
Status Report
June 29, 2023
Filed under ,
A Reappraisal of Near-Tropical Ice Stability on Mars
Theoretical stability of subsurface water-ice with respect to diffusion for a) flat surfaces b) 30° pole-facing slopes, using a nominal near-surface humidity. The red curve is the 10% Water-Equivalent Hydrogen contour, which is a good proxy for the presence of water ice in the shallow subsurface (Pathare et al., 2018). White dots indicate exposed water ice along cliff scarps and impact craters as reported in Dundas, Becerra, et al. (2021); Dundas et al. (2023) White diamonds indicate exposed water ice along gullies (Khuller & Christensen, 2021). — astro-ph.EP

Two arguments have suggested the presence of subsurface water ice at latitudes lower than 30° Mars.

First, the absence of CO2 frost on pole-facing slopes was explained by the presence of subsurface ice.

Second, models suggested that subsurface ice could be stable underneath these slopes. We revisit these arguments with a new slope microclimate model.

Our model shows that below 30° latitude, slopes are warmer than previously estimated as the air above is heated by warm surrounding plains. This additional heat prevents the formation of CO2 and subsurface water ice for most slopes. Higher than 30°S, our model suggests the presence of subsurface water ice.

In sparse cases (steep dusty slopes), subsurface ice may exist down to 25°S. While hypothetical unstable ice deposits cannot be excluded by our model, our results suggest that water ice is rarer than previously thought in the +- 30° latitude range considered for human exploration.

L.Lange, F.Forget, M.Vincendon, A.Spiga, E.Vos, O.Aharonson, E.Millour, R.Vandemeulebrouck, A.Bierjon

Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2306.16987 [astro-ph.EP] (or arXiv:2306.16987v1 [astro-ph.EP] for this version)
Submission history
From: Lucas Lange
[v1] Thu, 29 Jun 2023 14:44:33 UTC (11,232 KB)


Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻