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1. Microstructure-based modelling of snow mechanics: experimental evaluation of the cone penetration test

Author

C. Herny, P. Hagenmuller, G. Chambon, I. Peinke, and J. Roulle

Subjects
Environmental sciences, GE1-350, Geology, QE1-996.5
Abstract

Snow is a complex porous material presenting a variety of microstructural patterns. This microstructure largely controls the mechanical properties of snow, although the relation between the micro and macro properties remains to be better understood. Recent developments based on the discrete element method (DEM) and three-dimensional microtomographic data make it possible to reproduce numerically the brittle mechanical behaviour of snow. However, these developments lack experimental evaluation so far. In this study, we evaluate a DEM numerical model by reproducing cone penetration tests on centimetric snow samples. The microstructures of different natural snow samples were captured with X-ray microtomography before and after the cone penetration test, from which the grain displacements induced by the cone could be inferred. The tests were conducted with a modified snow micropenetrometer (5 mm cone diameter), which recorded the force profile at a high resolution. In the numerical model, an elastic–brittle cohesive contact law between snow grains was used to represent the cohesive bonds. The initial positions of the grains and their contacts were directly derived from the tomographic images. The numerical model was evaluated by comparing the measured force profiles and the grain displacement fields. Overall, the model satisfactorily reproduced the force profiles in terms of mean macroscopic force (mean relative error of about 20 %) and the amplitude of force fluctuations (mean relative error of about 55 %), while the correlation length of force fluctuations was more difficult to reproduce (mean relative error of about 40 % for two samples out of four and by a factor ≥ 8 for the other two). These characteristics were, as expected, highly dependent on the tested sample microstructure, but they were also sensitive to the choice of the micromechanical parameters describing the contact law. A scaling law was proposed between the mechanical parameters, the initial microstructure characteristics and the mean macroscopic force obtained with the DEM numerical model. The model could also reproduce the measured deformation around the cone tip (mean grain displacement relative error of 57 % along the horizontal axis), with a smaller sensitivity to the contact law parameterisation in this case. These detailed comparisons between numerical and experimental results give confidence to the reliability of the numerical modelling strategy and opens promising prospects to improve the understanding of snow mechanical behaviour.

Published
2024
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2. Solar-System-Wide Significance of Mars Polar Science

Author

J. J. Plaut, Colman Gallagher, Stephen R. Lewis, J. Bapst, C. Andres, John F. Mustard, S. F. A. Cartwright, Lauren A. Edgar, Susan J. Conway, Alan D. Howard, Michael Mischna, Gareth A. Morgan, Maria E. Banks, S. Diniega, Mark L. Skidmore, A. Van Brenen, Carol R. Stoker, Ralf Jaumann, Charity M. Phillips-Lander, Ali M. Bramson, Jennifer L. Whitten, Michael Daly, Michael H. Hecht, Solmaz Adeli, Manish R. Patel, N. Oliveira, S. Mukherjee, Matthew Chojnacki, Kimberly D. Seelos, F. Foss, S. Nerozzi, John E. Moores, Patricio Becerra, Nathaniel E. Putzig, Michael T. Mellon, Vince Eke, Margaret E. Landis, P. B. James, U. Gayathri, F. Bernardini, John Wilson, J. M. Widmer, J. Chesal, Alexey A. Pankine, Klaus-Michael Aye, C. Stuurman, Andrea Coronato, Z. Yoldi, C. Rezza, L. E. McKeown, Edwin S. Kite, B. Hartmann, Ákos Kereszturi, Melinda A. Kahre, Kennda Lynch, M. M. Sori, Alain Khayat, A. Kleinboehl, Matteo Crismani, Scott D. Guzewich, L. R. Lozano, Daniel J. McCleese, Norbert Schorghofer, O. Karatekin, Cynthia L. Dinwiddie, Gordon R. Osinski, Lori K. Fenton, Luca Montabone, Andreas Johnsson, Roberto Orosei, Peter C. Thomas, J. P. Knightly, Matthew R. Balme, Claire E. Newman, Eldar Noe Dobrea, Joseph A. MacGregor, Ernst Hauber, A. C. Pascuzzo, Jennifer Hanley, Bryana L. Henderson, Oded Aharonson, German Martinez, Timothy N. Titus, M. R. Perry, Tanguy Bertrand, P. A. Johnson, Maurizio Pajola, Shane Byrne, Matthew A. Siegler, Anya Portyankina, Nicolas Thomas, R. Karimova, C. Orgel, Michelle Koutnik, Leslie K. Tamppari, Amy McAdam, James A. Whiteway, Briony Horgan, Frances E. G. Butcher, E. Vos, François Forget, Christine S. Hvidberg, Vincent Chevrier, Travis F. Hager, Roland M. B. Young, T. G. Cave, Peter L. Read, M. R. Elmaary, Shannon M. Hibbard, C. J. Hansen, Paul O. Hayne, David A. Crown, J. C. Stern, J. C. Echaurren, I. Mishev, P. Russell, Roger N. Clark, Hanna G. Sizemore, J. W. Holt, F. Chuang, Adrian J. Brown, Colin M. Dundas, S. Ulamsec, G. Luizzi, Isaac B. Smith, Anna Łosiak, Peter Fawdon, David L. Goldsby, Alfred S. McEwen, C. Amos, S. E. Wood, C. Cesar, David E. Stillman, R. W. Obbard, Ralph D. Lorenz, A. Svensson, Ryan C. Ewing, Aymeric Spiga, B. S. Tober, T. Meng, P. Acharya, S. M. Milkovich, Paul Streeter, Kris Zacny, P. Sinha, Joseph S. Levy, Don Banfield, Eric I. Petersen, K. E. Herkenhoff, J. L. Eigenbrode, S. Piqueux, Mackenzie Day, Renyu Hu, Gregory Michael, James W. Head, Alejandro Soto, Richard Massey, A. R. Khuller, P. B. Buhler, S. Clifford, Samuel P. Kounaves, Daniel C. Berman, K. E. Mesick, Bernard Schmitt, Wendy M. Calvin, J. C. Johnson, David A. Fisher, C. Neisch, Robert L. Staehle, C. Herny, D. E. Lalich, Edgard G. Rivera-Valentín, David E. Smith, Anshuman Bhardwaj, Jorge Rabassa, Anna Grau Galofre, Alice Lucchetti, Lydia Sam, A. M. Rutledge, and A. J. Cross

Subjects
polar science, geology, Solar System, Habitability, water, ice, Mars, Mars Exploration Program, Astrobiology, missions, Planetary science, Planet, Polar, Climate record, climate, Geology
Abstract

Mars Polar Science is an integrated, compelling system that serves as a nearby analogue to numerous other planets, supports human exploration, and habitability. Mars possesses the closest and most easily accessible layered ice deposits outside of Earth, and accessing those layers to read the climate record would be a triumph for planetary science.

Published
2021

3. Wind tunnel experimentation of ice particles transport in Martian-like environment

Author

S. Carpy, Maï Bordiec, Olivier Bourgeois, Zurine Yoldi, C. Herny, Nicolas Thomas, Jonathan Merrison, and Jacob Iversen

Subjects
Martian, Environmental science, Wind tunnel, Astrobiology
Abstract

Introduction: The transport of ice by wind plays a major role in the surface mass balance of polar caps [1, 2]. Ice can be redistributed by wind due to (1) transport of ice particles and/or (2) transport of water vapour associated with sublimation/condensation. On Mars, although the low atmospheric density is less favourable for the transport of particles than on Earth, both dust and sand have been observed to be transported by wind [3,4]. Despite ice aeolian landforms have been observed at the surface of the North Polar Cap of Mars [2, 5, 6], ice particle transport has not been directly observed on the Martian surface. Similarly, no laboratory studies of snow/ice particle transport under Martian-like conditions have been attempted thus far due to the complexity of the material. In this study we performed experiments of ice particle transport in a wind-flow under low temperatures and low pressures. From the experiments, threshold shear velocity of water ice particle transport is retrieved for different pressures and sizes in order to evaluate the plausibility of ice particle wind-driven transportation at the surface of Mars. The North Polar Cap of Mars: The Martian atmosphere is thin (7 mbar), cold (220 K) and dry (< 80 μm-pr) [7]. These conditions favoured ice sublimation/condensation processes. Spectral analyses [8, 9] suggested the optical ice grain sizes to vary between 10 μm to about 2000 μm for the seasonal frost and surface of the perennial North polar cap. But, the mechanisms of ice deposition are not well established. It can potentially come from vapour condensation directly onto the surface [9] or from snow fall [10]. This will affect the shape and size of ice particles and degree of ice sintering, which all influence the shear velocity threshold. The North polar cap experiences a permanent katabatic wind regime [11] with a typical friction shear velocity u* about 0.2 m.s-1. The complex interaction between the cryosphere and the wind leads to the formation of aeolian features at different scales [2, 5, 6]. Wind tunnel experiments: We performed experiments using the environmental wind tunnel AWTSII at Aarhus University. It is a cylindrical vacuum chamber, housing a recirculating wind tunnel about 8 m long, 2 m wide and 1 m high [12]. The facility can achieve a turbulent boundary layer flow at both low temperature and low pressure. The ice samples were produced by using the Setup for production of Icy Planetary Analogues [13]. The ice samples were sieved (125 - 250 μm, 250 - 500 μm, 500 - 2000 μm) as a monolayer on a plate covered with volcanic regolith (125 μm). The fan speed was increased by steps (shear velocity u* = 0 to 2 m.s-1) and the wind flow characterized by laser Doppler anemometry. The removal of ice particles was monitored by webcam. We performed the experiments for the different particle shapes and sizes for 4 different air pressures; 40, 100, 500 and 1000 mbar. The air temperature was maintained low (~-25°C) close to the sample plate to prevent the ice melting, sublimating and sintering. Threshold shear velocity calculation: The threshold shear velocity was determined from analysis of acquired images. When bright ice particles are removed from the dark volcanic regolith plate, the reflectance of the surface decreases. Black and white reference targets are placed close to the sample plate in the field of view of the webcam. The reflectance evolution of a region of interest (ROI) on the sample plate is calculated as follow: reflectance = (ROI – black target)/(white target – black target) The reflectance serves as a proxy for ice mass removal. For each image the reflectance is linked to the corresponding shear velocity. In most of the cases performed, the reflectance is constant until a certain wind speed and then decreases. To determine the threshold shear velocity uth, we set the threshold reflectance at 10% decrease from the first image at u* = 0 m.s-1. Results and conclusion: We have performed for the 1st time experiments of ice particles transportation at low pressure in a planetary wind tunnel. The averaged threshold shear velocity obtained at 1000 mbar, uth = 0.4 m.s-1, is consistent with theoretical and experimental calculation of ice/snow at terrestrial condition [14, 15], from 0.3 m.s-1 to 0.6 m.s-1 for range of ice particles sizes selected, supporting our set-up reliability. The shear velocity increases significantly as the pressure decreases. The influence of the ice grain sizes is not clear and more experiments are required. The results should then be scaled to Martian gravity in order to compare the results to wind speed simulations and conclude about the likeliness of transport of ice particles by wind at the surface of Mars. References: [1] Das I. et al. (2013) Nature Geoscience, 6, 367-371. [2] Howard A. D. (2000) Icarus, 144, 267-288. [3] Cantor B. A. et al. (2010) Icarus, 208, 61-81. [4] Bridges B. A. et al. (2012) Geology, 40, 31-34. [5] Smith I. B. and Holt J. (2010) Nature, 465, 450-453. [6] Herny C. et al. (2014) EPSL, 403, 56-66. [7] Pankine A. A. et al. (2010) Icarus, 210, 5871. [8] Langevin Y. et al. (2005) Science, 307, 1584-6. [9] Appéré T. et al. (2011) JGR : Planets, 116, E05001. [10] Spiga A. et al. (2017) Nature Geoscience, 10, 652-657. [11] Spiga A. et al. (2011) PSS, 59, 915-922. [12] Holstein-Rathlou C. et al. (2014) Am. Met. Society, 31, 447-457. [13] Pommerol A. et al. (2019) Space Sci. Rev., 215. [14] Shao Y. and Lu H. (2000) JGR, 105, 437-443. [15] Clifton A. et al. (2006) JoG, 52, 585-596. [16] Herny C. et al. (2016) 6th MPSC, Abstract #6075. [17] Bordiec M. et al. (2018) ICAR X. Acknowledgements: This work has been fund by Europlanet (Europlanet 2020 RI has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No 654208). This work has been supported by the University of Bern. This work has been carried out within the framework of the NCCR PlanetS supported by the Swiss National Science Foundation.

Published
2020

4. Past, Present, and Future of Mars Polar Science: Outcomes and Outlook from the 7th International Conference on Mars Polar Science and Exploration

Author

Zuriñe Yoldi, Andrea Coronato, Ganna Portyankina, Melinda A. Kahre, Patricio Becerra, Isaac Smith, J. Bapst, Leslie K. Tamppari, A. C. Pascuzzo, Jennifer L. Whitten, Anna Grau Galofre, P. B. Buhler, C. Herny, Serina Diniega, C. Andres, S. Nerozzi, J. Paul Knightly, Timothy N. Titus, Jorge Rabassa, Shannon M. Hibbard, Ali M. Bramson, and Jeremy Emmett

Subjects
0211 other engineering and technologies, Astronomy and Astrophysics, 02 engineering and technology, Mars Exploration Program, 010502 geochemistry & geophysics, 01 natural sciences, Astrobiology, Geophysics, Space and Planetary Science, Earth and Planetary Sciences (miscellaneous), Polar, Geology, 021101 geological & geomatics engineering, 0105 earth and related environmental sciences
Abstract

Mars Polar Science is a subfield of Mars science that encompasses all studies of the cryosphere of Mars and its interaction with the Martian environment. Every 4 yr, the community of scientists dedicated to this subfield meets to discuss new findings and debate open issues in the International Conference on Mars Polar Science and Exploration (ICMPSE). This paper summarizes the proceedings of the seventh ICMPSE and the progress made since the sixth edition. We highlight the most important advances and present the most salient open questions in the field today, as discussed and agreed upon by the participants of the conference. We also feature agreed-upon suggestions for future methods, measurements, instruments, and missions that would be essential to answering the main open questions presented. This work is thus an overview of the current status of Mars Polar Science and is intended to serve as a road map for the direction of the field during the next 4 yr and beyond, helping to shape its contribution within the larger context of planetary science and exploration.

Published
2021

5. Sedimentation waves on the Martian North Polar Cap: Analogy with megadunes in Antarctica

Author

Olivier Bourgeois, Sebastien Rodriguez, T. Appéré, C. Herny, Aymeric Spiga, Marion Massé, Isaac B. Smith, S. Carpy, S. Le Mouélic, Laboratoire de Planétologie et Géodynamique UMR6112 (LPG), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Nantes - Faculté des Sciences et des Techniques, Université de Nantes (UN)-Université de Nantes (UN)-Université d'Angers (UA), Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris), Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG ), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École des Ponts ParisTech (ENPC)-École polytechnique (X)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)

Subjects
Martian, geography, Katabatic wind, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Glacier, Geophysics, Snow, 01 natural sciences, Wavelength, Space and Planetary Science, Geochemistry and Petrology, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), Cryosphere, Sastrugi, [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology, Ice sheet, 010303 astronomy & astrophysics, Geology, 0105 earth and related environmental sciences
Abstract

International audience; Complex interactions between katabatic winds and the cryosphere may lead to the formation of sedimentation waves at the surface of ice sheets. These have been first described and named snow megadunes in Antarctica. Here we use topographic data, optical images, subsurface radar soundings and spectroscopic data acquired by Mars orbiters, to show that the surface of the Martian North Polar Cap displays two superimposed sets of sedimentation waves with differing wavelengths. These sedimentation waves have similarities with Antarctic snow megadunes regarding their surface morphology, texture, grain size asymmetry, and internal stratigraphic architecture. Both sets of Martian sedimentation waves present young ice and occasional sastrugi fields, indicative of net accumulation, on their shallow-dipping upwind sides, their tops and the intervening troughs. Old layers of dusty ice, indicative of net ablation, are exhumed on the steep-dipping downwind sides of the larger waves. Smooth surfaces of coarse-grained ice, indicative of reduced accumulation associated with sublimation metamorphism, cover the steep-dipping downwind sides of the smaller waves. These surface characteristics and the internal stratigraphy revealed by radar soundings are consistent with the interpretation that both sets of Martian sedimentation waves grow and migrate upwind in response to the development of periodic accumulation/ablation patterns controlled by katabatic winds. The recognition of these sedimentation waves provides the basis for the development of a common model of ice/wind interaction at the surface of Martian and terrestrial glaciers. Martian smaller waves, characterized by reduced net accumulation on their downwind sides, are analogous to Antarctic snow megadunes that have been described so far. A terrestrial equivalent remains to be discovered for the larger Martian waves, characterized by net ablation on their downwind sides. © 2014 Elsevier B.V.

Published
2014

6. Water induced sediment levitation enhances downslope transport on Mars.

Author

Raack J, Conway SJ, Herny C, Balme MR, Carpy S, and Patel MR

Abstract

On Mars, locally warm surface temperatures (~293 K) occur, leading to the possibility of (transient) liquid water on the surface. However, water exposed to the martian atmosphere will boil, and the sediment transport capacity of such unstable water is not well understood. Here, we present laboratory studies of a newly recognized transport mechanism: "levitation" of saturated sediment bodies on a cushion of vapor released by boiling. Sediment transport where this mechanism is active is about nine times greater than without this effect, reducing the amount of water required to transport comparable sediment volumes by nearly an order of magnitude. Our calculations show that the effect of levitation could persist up to ~48 times longer under reduced martian gravity. Sediment levitation must therefore be considered when evaluating the formation of recent and present-day martian mass wasting features, as much less water may be required to form such features than previously thought.

Published
2017
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