Relationship between Greenland Ice Sheet surface speed and modeled effective pressure
We use a numerical subglacial hydrology model and remotely sensed observations of Greenland Ice Sheet surface motion to test whether the inverse relationship between effective pressure and regional melt season surface speeds observed at individual sites holds on a regional scale. The model is forced...
Published in: | Journal of Geophysical Research: Earth Surface |
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Format: | Article in Journal/Newspaper |
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American Geophysical Union
2018
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Online Access: | https://doi.org/10.1029/2017JF004581 https://ora.ox.ac.uk/objects/uuid:736e19e5-f727-470a-bbbf-ce44cea488af |
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ftuloxford:oai:ora.ox.ac.uk:uuid:736e19e5-f727-470a-bbbf-ce44cea488af 2024-09-30T14:35:50+00:00 Relationship between Greenland Ice Sheet surface speed and modeled effective pressure Stevens, LA Hewitt, IJ Das, SB Behn, MD 2018-07-31 https://doi.org/10.1029/2017JF004581 https://ora.ox.ac.uk/objects/uuid:736e19e5-f727-470a-bbbf-ce44cea488af unknown American Geophysical Union doi:10.1029/2017JF004581 https://ora.ox.ac.uk/objects/uuid:736e19e5-f727-470a-bbbf-ce44cea488af https://doi.org/10.1029/2017JF004581 info:eu-repo/semantics/openAccess Journal article 2018 ftuloxford https://doi.org/10.1029/2017JF004581 2024-09-06T07:47:36Z We use a numerical subglacial hydrology model and remotely sensed observations of Greenland Ice Sheet surface motion to test whether the inverse relationship between effective pressure and regional melt season surface speeds observed at individual sites holds on a regional scale. The model is forced with daily surface runoff estimates for 2009 and 2010 across an ~8,000‐km2 region on the western margin. The overall subglacial drainage system morphology develops similarly in both years, with subglacial channel networks growing inland from the ice sheet margin and robust subglacial pathways forming over bedrock ridges. Modeled effective pressures are compared to contemporaneous regional surface speeds derived from TerraSAR‐X imagery to investigate spatial relationships. Our results show an inverse spatial relationship between effective pressure and ice speed in the mid‐melt season, when surface speeds are elevated, indicating that effective pressure is the dominant control on surface velocities in the mid‐melt season. By contrast, in the early and late melt seasons, when surface speeds are slower, effective pressure and surface speed have a positive relationship. Our results suggest that outside of the mid‐melt season, the influence of effective pressures on sliding speeds may be secondary to the influence of driving stress and spatially variable bed roughness. Article in Journal/Newspaper Greenland Ice Sheet ORA - Oxford University Research Archive Greenland Journal of Geophysical Research: Earth Surface 123 9 2258 2278 |
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Open Polar |
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ORA - Oxford University Research Archive |
op_collection_id |
ftuloxford |
language |
unknown |
description |
We use a numerical subglacial hydrology model and remotely sensed observations of Greenland Ice Sheet surface motion to test whether the inverse relationship between effective pressure and regional melt season surface speeds observed at individual sites holds on a regional scale. The model is forced with daily surface runoff estimates for 2009 and 2010 across an ~8,000‐km2 region on the western margin. The overall subglacial drainage system morphology develops similarly in both years, with subglacial channel networks growing inland from the ice sheet margin and robust subglacial pathways forming over bedrock ridges. Modeled effective pressures are compared to contemporaneous regional surface speeds derived from TerraSAR‐X imagery to investigate spatial relationships. Our results show an inverse spatial relationship between effective pressure and ice speed in the mid‐melt season, when surface speeds are elevated, indicating that effective pressure is the dominant control on surface velocities in the mid‐melt season. By contrast, in the early and late melt seasons, when surface speeds are slower, effective pressure and surface speed have a positive relationship. Our results suggest that outside of the mid‐melt season, the influence of effective pressures on sliding speeds may be secondary to the influence of driving stress and spatially variable bed roughness. |
format |
Article in Journal/Newspaper |
author |
Stevens, LA Hewitt, IJ Das, SB Behn, MD |
spellingShingle |
Stevens, LA Hewitt, IJ Das, SB Behn, MD Relationship between Greenland Ice Sheet surface speed and modeled effective pressure |
author_facet |
Stevens, LA Hewitt, IJ Das, SB Behn, MD |
author_sort |
Stevens, LA |
title |
Relationship between Greenland Ice Sheet surface speed and modeled effective pressure |
title_short |
Relationship between Greenland Ice Sheet surface speed and modeled effective pressure |
title_full |
Relationship between Greenland Ice Sheet surface speed and modeled effective pressure |
title_fullStr |
Relationship between Greenland Ice Sheet surface speed and modeled effective pressure |
title_full_unstemmed |
Relationship between Greenland Ice Sheet surface speed and modeled effective pressure |
title_sort |
relationship between greenland ice sheet surface speed and modeled effective pressure |
publisher |
American Geophysical Union |
publishDate |
2018 |
url |
https://doi.org/10.1029/2017JF004581 https://ora.ox.ac.uk/objects/uuid:736e19e5-f727-470a-bbbf-ce44cea488af |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland Ice Sheet |
genre_facet |
Greenland Ice Sheet |
op_relation |
doi:10.1029/2017JF004581 https://ora.ox.ac.uk/objects/uuid:736e19e5-f727-470a-bbbf-ce44cea488af https://doi.org/10.1029/2017JF004581 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1029/2017JF004581 |
container_title |
Journal of Geophysical Research: Earth Surface |
container_volume |
123 |
container_issue |
9 |
container_start_page |
2258 |
op_container_end_page |
2278 |
_version_ |
1811639059915735040 |