A Micro-Mechanical Model for the Transformation of Dry Polar Firn Into Ice Using the Level-Set Method
International audience Interpretation of greenhouse gas records in polar ice cores requires a good understanding of the mechanisms controlling gas trapping in polar ice, and therefore of the processes of densification and pore closure in firn (compacted snow). Current firn densification models are b...
Published in: | Frontiers in Earth Science |
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Online Access: | https://hal.science/hal-03031694 https://hal.science/hal-03031694/document https://hal.science/hal-03031694/file/feart-08-00101.pdf https://doi.org/10.3389/feart.2020.00101 |
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ftunivnantes:oai:HAL:hal-03031694v1 2023-05-15T13:35:39+02:00 A Micro-Mechanical Model for the Transformation of Dry Polar Firn Into Ice Using the Level-Set Method Fourteau, Kévin Gillet-Chaulet, Fabien Martinerie, Patricia Fain, Xavier Institut des Géosciences de l’Environnement (IGE) Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ) Université Grenoble Alpes (UGA) 2020-04-17 https://hal.science/hal-03031694 https://hal.science/hal-03031694/document https://hal.science/hal-03031694/file/feart-08-00101.pdf https://doi.org/10.3389/feart.2020.00101 en eng HAL CCSD Frontiers Media info:eu-repo/semantics/altIdentifier/doi/10.3389/feart.2020.00101 hal-03031694 https://hal.science/hal-03031694 https://hal.science/hal-03031694/document https://hal.science/hal-03031694/file/feart-08-00101.pdf doi:10.3389/feart.2020.00101 info:eu-repo/semantics/OpenAccess ISSN: 2296-6463 Frontiers in Earth Science https://hal.science/hal-03031694 Frontiers in Earth Science, 2020, 8, ⟨10.3389/feart.2020.00101⟩ [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment [SDE]Environmental Sciences info:eu-repo/semantics/article Journal articles 2020 ftunivnantes https://doi.org/10.3389/feart.2020.00101 2023-03-01T02:34:00Z International audience Interpretation of greenhouse gas records in polar ice cores requires a good understanding of the mechanisms controlling gas trapping in polar ice, and therefore of the processes of densification and pore closure in firn (compacted snow). Current firn densification models are based on a macroscopic description of the firn and rely on empirical laws and/or idealized geometries to obtain the equations governing the densification and pore closure. Here, we propose a physically-based methodology explicitly representing the porous structure and its evolution over time. In order to handle the complex geometry and topological changes that occur during firn densification, we rely on a Level-Set representation of the interface between the ice and the pores. Two mechanisms are considered for the displacement of the interface: (i) mass surface diffusion driven by local pore curvature and (ii) ice dislocation creep. For the latter, ice is modeled as a viscous material and the flow velocities are solutions of the Stokes equations. First applications show that the model is able to densify firn and split pores. Using the model in cold and arid conditions of the Antarctic plateau, we show that gas trapping models do not have to consider the reduced compressibility of closed pores compared to open pores in the deepest part of firns. Our results also suggest that the mechanism of curvature-driven surface diffusion does not result in pore splitting, and that ice creep has to be taken into account for pores to close. Future applications of this type of model could help quantify the evolution and closure of firn porous networks for various accumulation and temperature conditions. Article in Journal/Newspaper Antarc* Antarctic Université de Nantes: HAL-UNIV-NANTES Antarctic Handle The ENVELOPE(161.983,161.983,-78.000,-78.000) The Antarctic Frontiers in Earth Science 8 |
institution |
Open Polar |
collection |
Université de Nantes: HAL-UNIV-NANTES |
op_collection_id |
ftunivnantes |
language |
English |
topic |
[SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment [SDE]Environmental Sciences |
spellingShingle |
[SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment [SDE]Environmental Sciences Fourteau, Kévin Gillet-Chaulet, Fabien Martinerie, Patricia Fain, Xavier A Micro-Mechanical Model for the Transformation of Dry Polar Firn Into Ice Using the Level-Set Method |
topic_facet |
[SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment [SDE]Environmental Sciences |
description |
International audience Interpretation of greenhouse gas records in polar ice cores requires a good understanding of the mechanisms controlling gas trapping in polar ice, and therefore of the processes of densification and pore closure in firn (compacted snow). Current firn densification models are based on a macroscopic description of the firn and rely on empirical laws and/or idealized geometries to obtain the equations governing the densification and pore closure. Here, we propose a physically-based methodology explicitly representing the porous structure and its evolution over time. In order to handle the complex geometry and topological changes that occur during firn densification, we rely on a Level-Set representation of the interface between the ice and the pores. Two mechanisms are considered for the displacement of the interface: (i) mass surface diffusion driven by local pore curvature and (ii) ice dislocation creep. For the latter, ice is modeled as a viscous material and the flow velocities are solutions of the Stokes equations. First applications show that the model is able to densify firn and split pores. Using the model in cold and arid conditions of the Antarctic plateau, we show that gas trapping models do not have to consider the reduced compressibility of closed pores compared to open pores in the deepest part of firns. Our results also suggest that the mechanism of curvature-driven surface diffusion does not result in pore splitting, and that ice creep has to be taken into account for pores to close. Future applications of this type of model could help quantify the evolution and closure of firn porous networks for various accumulation and temperature conditions. |
author2 |
Institut des Géosciences de l’Environnement (IGE) Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ) Université Grenoble Alpes (UGA) |
format |
Article in Journal/Newspaper |
author |
Fourteau, Kévin Gillet-Chaulet, Fabien Martinerie, Patricia Fain, Xavier |
author_facet |
Fourteau, Kévin Gillet-Chaulet, Fabien Martinerie, Patricia Fain, Xavier |
author_sort |
Fourteau, Kévin |
title |
A Micro-Mechanical Model for the Transformation of Dry Polar Firn Into Ice Using the Level-Set Method |
title_short |
A Micro-Mechanical Model for the Transformation of Dry Polar Firn Into Ice Using the Level-Set Method |
title_full |
A Micro-Mechanical Model for the Transformation of Dry Polar Firn Into Ice Using the Level-Set Method |
title_fullStr |
A Micro-Mechanical Model for the Transformation of Dry Polar Firn Into Ice Using the Level-Set Method |
title_full_unstemmed |
A Micro-Mechanical Model for the Transformation of Dry Polar Firn Into Ice Using the Level-Set Method |
title_sort |
micro-mechanical model for the transformation of dry polar firn into ice using the level-set method |
publisher |
HAL CCSD |
publishDate |
2020 |
url |
https://hal.science/hal-03031694 https://hal.science/hal-03031694/document https://hal.science/hal-03031694/file/feart-08-00101.pdf https://doi.org/10.3389/feart.2020.00101 |
long_lat |
ENVELOPE(161.983,161.983,-78.000,-78.000) |
geographic |
Antarctic Handle The The Antarctic |
geographic_facet |
Antarctic Handle The The Antarctic |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
ISSN: 2296-6463 Frontiers in Earth Science https://hal.science/hal-03031694 Frontiers in Earth Science, 2020, 8, ⟨10.3389/feart.2020.00101⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.3389/feart.2020.00101 hal-03031694 https://hal.science/hal-03031694 https://hal.science/hal-03031694/document https://hal.science/hal-03031694/file/feart-08-00101.pdf doi:10.3389/feart.2020.00101 |
op_rights |
info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.3389/feart.2020.00101 |
container_title |
Frontiers in Earth Science |
container_volume |
8 |
_version_ |
1766068482964717568 |