Effect of Water Ice Content on Excavatability of Lunar Regolith

2006 ◽  
Author(s):  
Leslie Gertsch
Keyword(s):  
Lunar Regolith ◽  
Water Ice ◽  
Effect Of Water ◽  
Ice Content

scholarly journals Site-level model intercomparison of high latitude and high altitude soil thermal dynamics in tundra and barren landscapes

2014 ◽  
Vol 8 (5) ◽  
pp. 4959-5013 ◽  
Author(s):  
A. Ekici ◽  
S. Chadburn ◽  
N. Chaudhary ◽  
L. H. Hajdu ◽  
A. Marmy ◽  
...  
Keyword(s):  
High Arctic ◽  
Soil Freezing ◽  
Physical Processes ◽  
Thermal Dynamics ◽  
Water Ice ◽  
Temperature Regimes ◽  
Temperature Dynamics ◽  
Permafrost Soils ◽  
Level Model ◽  
Ice Content

Abstract. Modelling soil thermal dynamics at high latitudes and altitudes requires representations of specific physical processes such as snow insulation, soil freezing/thawing, as well as subsurface conditions like soil water/ice content and soil texture type. We have compared six different land models (JSBACH, ORCHIDEE, JULES, COUP, HYBRID8, LPJ-GUESS) at four different sites with distinct cold region landscape types (i.e. Schilthorn-Alpine, Bayelva-high Arctic, Samoylov-wet polygonal tundra, Nuuk-non permafrost Arctic) to quantify the importance of physical processes in capturing observed temperature dynamics in soils. This work shows how a range of models can represent distinct soil temperature regimes in permafrost and non-permafrost soils. Snow insulation is of major importance for estimating topsoil conditions and must be combined with accurate subsoil temperature dynamics to correctly estimate active layer thicknesses. Analyses show that land models need more realistic surface processes (such as detailed snow dynamics and moss cover with changing thickness/wetness) as well as better representations of subsoil thermal dynamics (i.e. soil heat transfer mechanism and correct parameterization of heat conductivity/capacities).

Ice or rock matrix? Improved quantitative imaging of Alpine permafrost evolution through time-lapse petrophysical joint inversion

2021 ◽  
Author(s):  
Johanna Klahold ◽  
Christian Hauck ◽  
Florian Wagner
Keyword(s):  
Liquid Water ◽  
Joint Inversion ◽  
Time Lapse ◽  
Swiss Alps ◽  
Permafrost Degradation ◽  
Rock Matrix ◽  
Validation Data ◽  
Water Ice ◽  
Borehole Temperature ◽  
Ice Content

<p>Quantitative estimation of pore fractions filled with liquid water, ice and air is one of the prerequisites in many permafrost studies and forms the basis for a process-based understanding of permafrost and the hazard potential of its degradation in the context of global warming. The volumetric ice content is however difficult to retrieve, since standard borehole temperature monitoring is unable to provide any ice content estimation. Geophysical methods offer opportunities to image distributions of permafrost constituents in a non-invasive manner. A petrophysical joint inversion was recently developed to determine volumetric water, ice, air and rock contents from seismic refraction and electrical resistivity data. This approach benefits from the complementary sensitivities of seismic and electrical data to the phase change between ice and liquid water. A remaining weak point was the unresolved petrophysical ambiguity between ice and rock matrix. Within this study, the petrophysical joint inversion approach is extended along the time axis and respective temporal constraints are introduced. If the porosity (and other time-invariant properties like pore water resistivity or Archie exponents) can be assumed invariant over the considered time period, water, ice and air contents can be estimated together with a temporally constant (but spatially variable) porosity distribution. It is hypothesized that including multiple time steps in the inverse problem increases the ratio of data and parameters and leads to a more accurate distinction between ice and rock content. Based on a synthetic example and a field data set from an Alpine permafrost site (Schilthorn, Swiss Alps) it is demonstrated that the developed time-lapse petrophysical joint inversion provides physically plausible solutions, in particular improved estimates for the volumetric fractions of ice and rock. The field application is evaluated with independent validation data including thaw depths derived from borehole temperature measurements and shows generally good agreement. As opposed to the conventional petrophysical joint inversion, its time-lapse extension succeeds in providing reasonable estimates of permafrost degradation at the Schilthorn monitoring site without <em>a priori </em>constraints on the porosity model.</p>

Electrical Properties Probe Measures Water/Ice Content of Martian Soils Using Impedance Spectroscopy

2007 ◽  
Author(s):  
M. G. Buehler ◽  
K. B. Chin ◽  
S. Seshadri ◽  
D. Keymeulen ◽  
R. C. Anderson ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Impedance Spectroscopy ◽  
Water Ice ◽  
Ice Content

scholarly journals Impact flash evolution of CO 2 ice, water ice, and frozen Martian and lunar regolith simulant targets

2020 ◽  
Vol 55 (10) ◽  
pp. 2301-2319
Author(s):  
Jon D. Tandy ◽  
Mark C. Price ◽  
Penny J. Wozniakiewicz ◽  
Mike J. Cole ◽  
Luke S. Alesbrook ◽  
...  
Keyword(s):  
Lunar Regolith ◽  
Water Ice ◽  
Lunar Regolith Simulant ◽  
Ice Water ◽  
Impact Flash

scholarly journals Site-level model intercomparison of high latitude and high altitude soil thermal dynamics in tundra and barren landscapes

2015 ◽  
Vol 9 (4) ◽  
pp. 1343-1361 ◽  
Author(s):  
A. Ekici ◽  
S. Chadburn ◽  
N. Chaudhary ◽  
L. H. Hajdu ◽  
A. Marmy ◽  
...  
Keyword(s):  
High Arctic ◽  
Soil Freezing ◽  
Soil Physics ◽  
Physical Processes ◽  
Freezing And Thawing ◽  
Thermal Dynamics ◽  
Water Ice ◽  
Temperature Regimes ◽  
Temperature Dynamics ◽  
Ice Content

Abstract. Modeling soil thermal dynamics at high latitudes and altitudes requires representations of physical processes such as snow insulation, soil freezing and thawing and subsurface conditions like soil water/ice content and soil texture. We have compared six different land models: JSBACH, ORCHIDEE, JULES, COUP, HYBRID8 and LPJ-GUESS, at four different sites with distinct cold region landscape types, to identify the importance of physical processes in capturing observed temperature dynamics in soils. The sites include alpine, high Arctic, wet polygonal tundra and non-permafrost Arctic, thus showing how a range of models can represent distinct soil temperature regimes. For all sites, snow insulation is of major importance for estimating topsoil conditions. However, soil physics is essential for the subsoil temperature dynamics and thus the active layer thicknesses. This analysis shows that land models need more realistic surface processes, such as detailed snow dynamics and moss cover with changing thickness and wetness, along with better representations of subsoil thermal dynamics.

scholarly journals Influence of sub- and super-solar metallicities on the composition of solid planetary building blocks

2019 ◽  
Vol 633 ◽  
pp. A10 ◽  
Author(s):  
Bertram Bitsch ◽  
Chiara Battistini
Keyword(s):  
Planet Formation ◽  
Building Blocks ◽  
The Other ◽  
Chemical Model ◽  
Stellar Abundances ◽  
Water Ice ◽  
Other Hand ◽  
Iron Abundance ◽  
Ice Content ◽  
Ice Fraction

The composition of the protoplanetary disc is thought to be linked to the composition of the host star, where a higher overall metallicity provides the building blocks for planets. However, most of the planet formation simulations only link the stellar iron abundance [Fe/H] to planet formation and the iron abundance in itself is used as a proxy to scale all elements. On the other hand, large surveys of stellar abundances show that this is not true. Here we use stellar abundances from the GALAH surveys to determine the average detailed abundances of Fe, Si, Mg, O, and C for a broad range of host star metallicities with [Fe/H] spanning from −0.4 to +0.4. Using an equilibrium chemical model that features the most important rock-forming compounds as well as volatile contributions of H2O, CO2, CH4, and CO, we calculate the chemical composition of solid planetary building blocks around stars with different metallicities. Solid building blocks that are formed entirely interior to the water ice line (T > 150 K) only show an increase in Mg2SiO4 and a decrease in MgSiO3 for increasing host star metallicity, which is related to the increase of [Mg/Si] for higher [Fe/H]. Solid planetary building blocks forming exterior to the water ice line (T < 150 K), on the other hand, show dramatic changes in their composition. In particular, the water ice content decreases from around ~50% at [Fe/H] = −0.4 to ~6% at [Fe/H] = 0.4 in our chemical model. This is mainly caused by the increasing C/O ratio with increasing [Fe/H], which binds most of the oxygen in gaseous CO and CO2, resulting in a small water ice fraction. Planet formation simulations coupled with the chemical model confirm these results by showing that the water ice content of super-Earths decreases with increasing host star metallicity due to the increased C/O ratio. This decrease of the water ice fraction has important consequences for planet formation, planetary composition, and the eventual habitability of planetary systems formed around these high-metallicity stars.

Laboratory experiments to investigate sublimation rates of water ice in nighttime lunar regolith

Icarus ◽  
2017 ◽  
Vol 293 ◽  
pp. 180-184 ◽  
Author(s):  
Marcus Piquette ◽  
Mihály Horányi ◽  
S. Alan Stern
Keyword(s):  
Laboratory Experiments ◽  
Lunar Regolith ◽  
Water Ice ◽  
Sublimation Rates

scholarly journals The formation of molecular hydrogen from water ice in the lunar regolith by energetic charged particles

2013 ◽  
Vol 118 (6) ◽  
pp. 1257-1264 ◽  
Author(s):  
A. P. Jordan ◽  
T. J. Stubbs ◽  
C. J. Joyce ◽  
N. A. Schwadron ◽  
H. E. Spence ◽  
...  
Keyword(s):  
Molecular Hydrogen ◽  
Lunar Regolith ◽  
Charged Particles ◽  
Water Ice
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