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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Copernicus Publications
2017
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Online Access: | https://doi.org/10.5194/tc-11-669-2017 http://www.the-cryosphere.net/11/669/2017/tc-11-669-2017.pdf https://doaj.org/article/b956711b881c4d8ea55608e550a3f8ff |
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fttriple:oai:gotriple.eu:oai:doaj.org/article:b956711b881c4d8ea55608e550a3f8ff 2023-05-15T16:21:04+02:00 Liquid water content in ice estimated through a full-depth ground radar profile and borehole measurements in western Greenland J. Brown J. Harper N. Humphrey 2017-03-01 https://doi.org/10.5194/tc-11-669-2017 http://www.the-cryosphere.net/11/669/2017/tc-11-669-2017.pdf https://doaj.org/article/b956711b881c4d8ea55608e550a3f8ff en eng Copernicus Publications 1994-0416 1994-0424 doi:10.5194/tc-11-669-2017 http://www.the-cryosphere.net/11/669/2017/tc-11-669-2017.pdf https://doaj.org/article/b956711b881c4d8ea55608e550a3f8ff undefined The Cryosphere, Vol 11, Iss 1, Pp 669-679 (2017) geo envir Journal Article https://vocabularies.coar-repositories.org/resource_types/c_6501/ 2017 fttriple https://doi.org/10.5194/tc-11-669-2017 2023-01-22T19:28:38Z 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. Article in Journal/Newspaper glacier Greenland Ice Sheet The Cryosphere Unknown Greenland The Cryosphere 11 1 669 679 |
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geo envir J. Brown J. Harper N. Humphrey Liquid water content in ice estimated through a full-depth ground radar profile and borehole measurements in western Greenland |
topic_facet |
geo envir |
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 |
Article in Journal/Newspaper |
author |
J. Brown J. Harper N. Humphrey |
author_facet |
J. Brown J. Harper N. Humphrey |
author_sort |
J. Brown |
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 |
publisher |
Copernicus Publications |
publishDate |
2017 |
url |
https://doi.org/10.5194/tc-11-669-2017 http://www.the-cryosphere.net/11/669/2017/tc-11-669-2017.pdf https://doaj.org/article/b956711b881c4d8ea55608e550a3f8ff |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
glacier Greenland Ice Sheet The Cryosphere |
genre_facet |
glacier Greenland Ice Sheet The Cryosphere |
op_source |
The Cryosphere, Vol 11, Iss 1, Pp 669-679 (2017) |
op_relation |
1994-0416 1994-0424 doi:10.5194/tc-11-669-2017 http://www.the-cryosphere.net/11/669/2017/tc-11-669-2017.pdf https://doaj.org/article/b956711b881c4d8ea55608e550a3f8ff |
op_rights |
undefined |
op_doi |
https://doi.org/10.5194/tc-11-669-2017 |
container_title |
The Cryosphere |
container_volume |
11 |
container_issue |
1 |
container_start_page |
669 |
op_container_end_page |
679 |
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1766009091114663936 |