A permeameter for temperate ice: first results on permeability sensitivity to grain size
Abstract Results of ice-stream models that treat temperate ice deformation as a two-phase flow are sensitive to the ice permeability. We have constructed and begun using a custom, falling-head permeameter for measuring the permeability of temperate, polycrystalline ice. Chilled water is passed throu...
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Cambridge University Press (CUP)
2022
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Online Access: | http://dx.doi.org/10.1017/jog.2021.136 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143021001362 |
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crcambridgeupr:10.1017/jog.2021.136 2024-06-23T07:54:15+00:00 A permeameter for temperate ice: first results on permeability sensitivity to grain size Fowler, Jacob R. Iverson, Neal R. US National Science Foundation 2022 http://dx.doi.org/10.1017/jog.2021.136 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143021001362 en eng Cambridge University Press (CUP) https://creativecommons.org/licenses/by/4.0/ Journal of Glaciology volume 68, issue 270, page 764-774 ISSN 0022-1430 1727-5652 journal-article 2022 crcambridgeupr https://doi.org/10.1017/jog.2021.136 2024-06-05T04:03:16Z Abstract Results of ice-stream models that treat temperate ice deformation as a two-phase flow are sensitive to the ice permeability. We have constructed and begun using a custom, falling-head permeameter for measuring the permeability of temperate, polycrystalline ice. Chilled water is passed through an ice disk that is kept at the pressure-melting temperature while the rate of head decrease indicates the permeability. Fluorescein dye in the water allows water-vein geometry to be studied using fluorescence microscopy. Water flow over durations of seconds to hours is Darcian, and for grain diameter d increasing from 1.7 to 8.9 mm, average permeability decreases from 2 × 10 −12 to 4 × 10 −15 m 2 . In tests with dye on fine ( d = 2 mm) and coarse ( d = 7 mm) ice, average area-weighted vein radii are nearly equal, 41 and 34 μm, respectively. These average radii, if included in a theory slightly modified from Nye and Frank (1973), yield permeability values within a factor of 2.0 of best-fit values based on regression of the data. Permeability values depend on d −3.4 , rather than d −2 as predicted by models if vein radii are considered independent of d . In future experiments, the dependence of permeability on liquid water content will be measured. Article in Journal/Newspaper Journal of Glaciology Cambridge University Press Journal of Glaciology 1 11 |
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Open Polar |
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Cambridge University Press |
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crcambridgeupr |
language |
English |
description |
Abstract Results of ice-stream models that treat temperate ice deformation as a two-phase flow are sensitive to the ice permeability. We have constructed and begun using a custom, falling-head permeameter for measuring the permeability of temperate, polycrystalline ice. Chilled water is passed through an ice disk that is kept at the pressure-melting temperature while the rate of head decrease indicates the permeability. Fluorescein dye in the water allows water-vein geometry to be studied using fluorescence microscopy. Water flow over durations of seconds to hours is Darcian, and for grain diameter d increasing from 1.7 to 8.9 mm, average permeability decreases from 2 × 10 −12 to 4 × 10 −15 m 2 . In tests with dye on fine ( d = 2 mm) and coarse ( d = 7 mm) ice, average area-weighted vein radii are nearly equal, 41 and 34 μm, respectively. These average radii, if included in a theory slightly modified from Nye and Frank (1973), yield permeability values within a factor of 2.0 of best-fit values based on regression of the data. Permeability values depend on d −3.4 , rather than d −2 as predicted by models if vein radii are considered independent of d . In future experiments, the dependence of permeability on liquid water content will be measured. |
author2 |
US National Science Foundation |
format |
Article in Journal/Newspaper |
author |
Fowler, Jacob R. Iverson, Neal R. |
spellingShingle |
Fowler, Jacob R. Iverson, Neal R. A permeameter for temperate ice: first results on permeability sensitivity to grain size |
author_facet |
Fowler, Jacob R. Iverson, Neal R. |
author_sort |
Fowler, Jacob R. |
title |
A permeameter for temperate ice: first results on permeability sensitivity to grain size |
title_short |
A permeameter for temperate ice: first results on permeability sensitivity to grain size |
title_full |
A permeameter for temperate ice: first results on permeability sensitivity to grain size |
title_fullStr |
A permeameter for temperate ice: first results on permeability sensitivity to grain size |
title_full_unstemmed |
A permeameter for temperate ice: first results on permeability sensitivity to grain size |
title_sort |
permeameter for temperate ice: first results on permeability sensitivity to grain size |
publisher |
Cambridge University Press (CUP) |
publishDate |
2022 |
url |
http://dx.doi.org/10.1017/jog.2021.136 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143021001362 |
genre |
Journal of Glaciology |
genre_facet |
Journal of Glaciology |
op_source |
Journal of Glaciology volume 68, issue 270, page 764-774 ISSN 0022-1430 1727-5652 |
op_rights |
https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1017/jog.2021.136 |
container_title |
Journal of Glaciology |
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1 |
op_container_end_page |
11 |
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1802646348349046784 |