Liquid water content in ice estimated through a full-depth ground radar profile and borehole measurements in western Greenland
Liquid water content (wetness) within glacier ice is known to strongly control ice viscosity and ice deformation processes. Little is known about wetness of ice on the outer flanks of the Greenland Ice Sheet, where a temperate layer of basal ice exists. This study integrates borehole and radar surve...
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ftcopernicus:oai:publications.copernicus.org:tc54638 2023-05-15T16:21:03+02:00 Liquid water content in ice estimated through a full-depth ground radar profile and borehole measurements in western Greenland Brown, Joel Harper, Joel Humphrey, Neil 2018-09-27 application/pdf https://doi.org/10.5194/tc-11-669-2017 https://tc.copernicus.org/articles/11/669/2017/ eng eng doi:10.5194/tc-11-669-2017 https://tc.copernicus.org/articles/11/669/2017/ eISSN: 1994-0424 Text 2018 ftcopernicus https://doi.org/10.5194/tc-11-669-2017 2020-07-20T16:23:48Z Liquid water content (wetness) within glacier ice is known to strongly control ice viscosity and ice deformation processes. Little is known about wetness of ice on the outer flanks of the Greenland Ice Sheet, where a temperate layer of basal ice exists. This study integrates borehole and radar surveys collected in June 2012 to provide direct estimates of englacial ice wetness in the ablation zone of western Greenland. We estimate electromagnetic propagation velocity of the ice body by inverting reflection travel times from radar data. Our inversion is constrained by ice thickness measured in boreholes and by positioning of a temperate–cold ice boundary identified in boreholes. Electromagnetic propagation velocities are consistent with a depth-averaged wetness of ∼ 0.5–1.1 %. The inversion indicates that wetness within the ice varies from < 0.1 % in an upper cold layer to ∼ 2.9–4.6 % in a 130–150 m thick temperate layer located above the glacier bed. Such high wetness should yield high rates of shear strain, which need to be accounted for in glacial flow models that focus on the ablation zone of Greenland. This high wetness also needs to be accounted for when determining ice thickness from radar measurements. Text glacier Greenland Ice Sheet Copernicus Publications: E-Journals Greenland The Cryosphere 11 1 669 679 |
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Open Polar |
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Copernicus Publications: E-Journals |
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ftcopernicus |
language |
English |
description |
Liquid water content (wetness) within glacier ice is known to strongly control ice viscosity and ice deformation processes. Little is known about wetness of ice on the outer flanks of the Greenland Ice Sheet, where a temperate layer of basal ice exists. This study integrates borehole and radar surveys collected in June 2012 to provide direct estimates of englacial ice wetness in the ablation zone of western Greenland. We estimate electromagnetic propagation velocity of the ice body by inverting reflection travel times from radar data. Our inversion is constrained by ice thickness measured in boreholes and by positioning of a temperate–cold ice boundary identified in boreholes. Electromagnetic propagation velocities are consistent with a depth-averaged wetness of ∼ 0.5–1.1 %. The inversion indicates that wetness within the ice varies from < 0.1 % in an upper cold layer to ∼ 2.9–4.6 % in a 130–150 m thick temperate layer located above the glacier bed. Such high wetness should yield high rates of shear strain, which need to be accounted for in glacial flow models that focus on the ablation zone of Greenland. This high wetness also needs to be accounted for when determining ice thickness from radar measurements. |
format |
Text |
author |
Brown, Joel Harper, Joel Humphrey, Neil |
spellingShingle |
Brown, Joel Harper, Joel Humphrey, Neil Liquid water content in ice estimated through a full-depth ground radar profile and borehole measurements in western Greenland |
author_facet |
Brown, Joel Harper, Joel Humphrey, Neil |
author_sort |
Brown, Joel |
title |
Liquid water content in ice estimated through a full-depth ground radar profile and borehole measurements in western Greenland |
title_short |
Liquid water content in ice estimated through a full-depth ground radar profile and borehole measurements in western Greenland |
title_full |
Liquid water content in ice estimated through a full-depth ground radar profile and borehole measurements in western Greenland |
title_fullStr |
Liquid water content in ice estimated through a full-depth ground radar profile and borehole measurements in western Greenland |
title_full_unstemmed |
Liquid water content in ice estimated through a full-depth ground radar profile and borehole measurements in western Greenland |
title_sort |
liquid water content in ice estimated through a full-depth ground radar profile and borehole measurements in western greenland |
publishDate |
2018 |
url |
https://doi.org/10.5194/tc-11-669-2017 https://tc.copernicus.org/articles/11/669/2017/ |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
glacier Greenland Ice Sheet |
genre_facet |
glacier Greenland Ice Sheet |
op_source |
eISSN: 1994-0424 |
op_relation |
doi:10.5194/tc-11-669-2017 https://tc.copernicus.org/articles/11/669/2017/ |
op_doi |
https://doi.org/10.5194/tc-11-669-2017 |
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The Cryosphere |
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11 |
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1 |
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669 |
op_container_end_page |
679 |
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1766009061317279744 |