Maps of Subsurface Hydrogen from the High Energy Neutron Detector, Mars Odyssey

Митрофанов, И. Г.; Anfimov, D.; Kozyrev, A.; Litvak, M. L.; Санин, А. Б.; Tretyakov, V. I.; Krylov, A. R.; Швецов, В. Н.; Boynton, W. V.; Shinohara, C.; Hamara, D.; Saunders, R. S.

doi:10.1126/science.1073616

Cited by 357 publications

(228 citation statements)

References 11 publications

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“…No clear relationship between polygon dimension and ground-ice content, which increases with latitude (e.g., Feldman et al, 2004), could be observed on Mars (Mangold et al, 2004;Mangold, 2005;Levy et al, 2009a). The size of the upland polygons (UP1) is consistent with the findings of the Gamma Ray Spectrometer (GRS) that only~4 tõ 10 wt.% water-ice equivalent exists currently in the upper surface layer (b1 m depth) in the regions between 45°S and 45°N Mitrofanov et al, 2002;Feldman et al, 2004). If higher ground-ice contents than in the upper layer occur deeper than 1 m, which was inferred from the dimension of the scalloped depressions (Morgenstern et al, 2007;Ulrich et al, 2010), seasonal thermal waves should not reach this depth at the present time (Mellon, 1997;Mangold et al, 2004).…”

Section: Genesis Of Mars Polygons and Environmental Implicationssupporting

confidence: 64%

Polygon pattern geomorphometry on Svalbard (Norway) and western Utopia Planitia (Mars) using high-resolution stereo remote-sensing data

et al. 2011

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Polygonal systems formed by thermal contraction cracking are complex landscape features widespread in terrestrial periglacial regions. The manner in which cracking occurs is controlled by various environmental factors and determines dimension, shape, and orientation of polygons. Analogous small-scale features are ubiquitous in Martian mid-and high-latitudes, and they are also inferred to originate from thermal contraction cracking. We studied the geomorphometry of polygonally-patterned ground on Svalbard to draw a terrestrial analogy to small-scale polygonal structures in scalloped terrain in Martian mid-latitudes. We performed a comparative quantitative terrain analysis based on high-resolution stereo remote-sensing data (HRSC-AX and HiRISE) in combination with terrestrial field data and multivariate statistics to determine the relationship of polygon geomorphometry to local environmental conditions. Results show that polygonal structures on Svalbard and in Utopia Planitia on Mars are similar with respect to their size and shape. A comparable thermal contraction cracking genesis is likely. Polygon evolution, however, is strongly related to regional and local landscape dynamics. Individual polygon dimensions and orthogonality vary according to age, thermal contraction cracking activity, and local subsurface conditions. Based on these findings, the effects of specific past and current environmental conditions on polygon formation on Mars must be considered. On both Earth and Mars, the smallest polygons represent young, recently-active low-centered polygons that formed in fine-grained ice-rich material. Small, low-centered Martian polygons show the closest analogy to terrestrial low-centered ice-wedge polygons. The formation of composite wedges could have occurred as a result of local geomorphological conditions during past Martian orbital configurations. Larger polygons reflect past climate conditions on both Earth and Mars. The present degradation of these polygons depends on relief and topographical situation. On Svalbard the thawing of ice wedges degrades high-centered polygons; in contrast, the present appearance of polygons in Utopia Planitia is primarily the result of contemporary dry degradation processes.

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Section: Genesis Of Mars Polygons and Environmental Implicationssupporting

confidence: 64%

Polygon pattern geomorphometry on Svalbard (Norway) and western Utopia Planitia (Mars) using high-resolution stereo remote-sensing data

et al. 2011

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“…However, the presence of water ice in the shallow subsurface midlatitude and polar regions Mitrofanov et al 2002;Byrne et al 2009), along with the detection of perchlorates in polar and equatorial soil Glavin et al 2013;Ming et al 2014) and of chloride-bearing deposits in the southern highlands at low and midlatitudes (Osterloo et al 2008), is important because they can melt this ice at Mars' present-day environmental conditions and produce liquid saline water (brine) (Clark 1978;Brass 1980;Clark and Van Hart 1981;Haberle et al 2001;Chevrier and Altheide 2008;Rennó et al 2009;McEwen et al 2011;Ojha et al 2015).…”

Section: Liquid Water and The H 2 O Cyclementioning

confidence: 99%

The Modern Near-Surface Martian Climate: A Review of In-situ Meteorological Data from Viking to Curiosity

et al. 2017

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We analyze the complete set of in-situ meteorological data obtained from the Viking landers in the 1970s to today's Curiosity rover to review our understanding of the modern near-surface climate of Mars, with focus on the dust, CO 2 and H 2 O cycles and their impact on the radiative and thermodynamic conditions near the surface. In particular, we provide values of the highest confidence possible for atmospheric opacity, atmospheric pressure, near-surface air temperature, ground temperature, near-surface wind speed and direction, and near-surface air relative humidity and water vapor content. Then, we study the diurnal, seasonal and interannual variability of these quantities over a span of more thanThe original version of this article was revised because due to an unfortunate turn of events a wrong value was published in Table 1. The resolution of the PHX pressure sensor was published as "0.1 mbar" whereas this value has now been corrected to "0.1 Pa" which is the correct value and should be regarded as the final version by the reader. B G.M. Martínez

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“…In 2002, GRS data, which are directly dependent on the concentrations of hydrogen, and therefore almost certainly upon the concentration of water, within roughly one meter of the surface, showed the presence of extensive ground ice within this upper meter above $50°latitude in both hemispheres (Feldman et al, 2002;Boynton et al, 2002;Mitrofanov et al, 2002); concentrations typically range from $2 to 5 wt% at $40°l atitude to $20 wt% at 60°latitude, generally increasing polewards . Ice-stability models, which are consistent with the GRS observations, show that ground ice within a meter, or less, of the surface should generally be stable above 45-55°lat-itude (e.g., Mellon and Jakosky, 1993;Allen and Kanner, 2007).…”

Section: Introductionmentioning

confidence: 99%

Scalloped terrains in the Peneus and Amphitrites Paterae region of Mars as observed by HiRISE

Lefort

Russell

Thomas

2010

Icarus

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Maps of Subsurface Hydrogen from the High Energy Neutron Detector, Mars Odyssey

Cited by 357 publications

References 11 publications

Polygon pattern geomorphometry on Svalbard (Norway) and western Utopia Planitia (Mars) using high-resolution stereo remote-sensing data

Polygon pattern geomorphometry on Svalbard (Norway) and western Utopia Planitia (Mars) using high-resolution stereo remote-sensing data

The Modern Near-Surface Martian Climate: A Review of In-situ Meteorological Data from Viking to Curiosity

Scalloped terrains in the Peneus and Amphitrites Paterae region of Mars as observed by HiRISE

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