Direct observations of evolving subglacial drainage beneath the Greenland Ice Sheet
©2014 Macmillan Publishers Limited. All rights reserved. Seasonal acceleration of the Greenland Ice Sheet is influenced by the dynamic response of the subglacial hydrologic system to variability in meltwater delivery to the bed via crevasses and moulins (vertical conduits connecting supraglacial wat...
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ftmichigantuniv:oai:digitalcommons.mtu.edu:michigantech-p-27717 2023-05-15T16:27:17+02:00 Direct observations of evolving subglacial drainage beneath the Greenland Ice Sheet Andrews, Lauren C. Catania, Ginny A. Hoffman, Matthew J. Gulley, Jason D. Lüthi, Martin P. Ryser, Claudia Hawley, Robert L. Neumann, Thomas A. 2015-10-02T07:00:00Z https://digitalcommons.mtu.edu/michigantech-p/8415 https://doi.org/10.1038/nature13796 unknown Digital Commons @ Michigan Tech https://digitalcommons.mtu.edu/michigantech-p/8415 https://doi.org/10.1038/nature13796 Michigan Tech Publications text 2015 ftmichigantuniv https://doi.org/10.1038/nature13796 2022-01-23T10:17:01Z ©2014 Macmillan Publishers Limited. All rights reserved. Seasonal acceleration of the Greenland Ice Sheet is influenced by the dynamic response of the subglacial hydrologic system to variability in meltwater delivery to the bed via crevasses and moulins (vertical conduits connecting supraglacial water to the bed of the ice sheet). As the melt season progresses, the subglacial hydrologic system drains supraglacial meltwater more efficiently, decreasing basal water pressure and moderating the ice velocity response to surface melting. However, limited direct observations of subglacial water pressure mean that the spatiotemporal evolution of the subglacial hydrologic system remains poorly understood. Here we show that ice velocity is well correlated with moulin hydraulic head but is out of phase with that of nearby (0.3-2 kilometres away) boreholes, indicating that moulins connect to an efficient, channelized component of the subglacial hydrologic system, which exerts the primary control on diurnal and multi-day changes in ice velocity. Our simultaneous measurements of moulin and borehole hydraulic head and ice velocity in the Paakitsoq region of western Greenland show that decreasing trends in ice velocity during the latter part of the melt season cannot be explained by changes in the ability of moulin-connected channels to convey supraglacial melt. Instead, these observations suggest that decreasing late-season ice velocity may be caused by changes in connectivity in unchannelized regions of the subglacial hydrologic system. Understanding this spatiotemporal variability in subglacial pressures is increasingly important because melt-season dynamics affect ice velocity beyond the conclusion of the melt season. Text Greenland Ice Sheet Michigan Technological University: Digital Commons @ Michigan Tech Greenland Nature 514 7520 80 83 |
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Michigan Technological University: Digital Commons @ Michigan Tech |
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©2014 Macmillan Publishers Limited. All rights reserved. Seasonal acceleration of the Greenland Ice Sheet is influenced by the dynamic response of the subglacial hydrologic system to variability in meltwater delivery to the bed via crevasses and moulins (vertical conduits connecting supraglacial water to the bed of the ice sheet). As the melt season progresses, the subglacial hydrologic system drains supraglacial meltwater more efficiently, decreasing basal water pressure and moderating the ice velocity response to surface melting. However, limited direct observations of subglacial water pressure mean that the spatiotemporal evolution of the subglacial hydrologic system remains poorly understood. Here we show that ice velocity is well correlated with moulin hydraulic head but is out of phase with that of nearby (0.3-2 kilometres away) boreholes, indicating that moulins connect to an efficient, channelized component of the subglacial hydrologic system, which exerts the primary control on diurnal and multi-day changes in ice velocity. Our simultaneous measurements of moulin and borehole hydraulic head and ice velocity in the Paakitsoq region of western Greenland show that decreasing trends in ice velocity during the latter part of the melt season cannot be explained by changes in the ability of moulin-connected channels to convey supraglacial melt. Instead, these observations suggest that decreasing late-season ice velocity may be caused by changes in connectivity in unchannelized regions of the subglacial hydrologic system. Understanding this spatiotemporal variability in subglacial pressures is increasingly important because melt-season dynamics affect ice velocity beyond the conclusion of the melt season. |
format |
Text |
author |
Andrews, Lauren C. Catania, Ginny A. Hoffman, Matthew J. Gulley, Jason D. Lüthi, Martin P. Ryser, Claudia Hawley, Robert L. Neumann, Thomas A. |
spellingShingle |
Andrews, Lauren C. Catania, Ginny A. Hoffman, Matthew J. Gulley, Jason D. Lüthi, Martin P. Ryser, Claudia Hawley, Robert L. Neumann, Thomas A. Direct observations of evolving subglacial drainage beneath the Greenland Ice Sheet |
author_facet |
Andrews, Lauren C. Catania, Ginny A. Hoffman, Matthew J. Gulley, Jason D. Lüthi, Martin P. Ryser, Claudia Hawley, Robert L. Neumann, Thomas A. |
author_sort |
Andrews, Lauren C. |
title |
Direct observations of evolving subglacial drainage beneath the Greenland Ice Sheet |
title_short |
Direct observations of evolving subglacial drainage beneath the Greenland Ice Sheet |
title_full |
Direct observations of evolving subglacial drainage beneath the Greenland Ice Sheet |
title_fullStr |
Direct observations of evolving subglacial drainage beneath the Greenland Ice Sheet |
title_full_unstemmed |
Direct observations of evolving subglacial drainage beneath the Greenland Ice Sheet |
title_sort |
direct observations of evolving subglacial drainage beneath the greenland ice sheet |
publisher |
Digital Commons @ Michigan Tech |
publishDate |
2015 |
url |
https://digitalcommons.mtu.edu/michigantech-p/8415 https://doi.org/10.1038/nature13796 |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland Ice Sheet |
genre_facet |
Greenland Ice Sheet |
op_source |
Michigan Tech Publications |
op_relation |
https://digitalcommons.mtu.edu/michigantech-p/8415 https://doi.org/10.1038/nature13796 |
op_doi |
https://doi.org/10.1038/nature13796 |
container_title |
Nature |
container_volume |
514 |
container_issue |
7520 |
container_start_page |
80 |
op_container_end_page |
83 |
_version_ |
1766016423722745856 |