Force balance along Isunnguata Sermia, west Greenland
Ice flows when gravity acts on gradients in surface elevation, producing driving stresses. In the Isunnguata Sermia and Russel Glacier catchments of western Greenland, a 50% decline in driving stress along a flow line is juxtaposed with increasing surface flow speed. Here, these circumstances are in...
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Online Access: | https://doi.org/10.3389/feart.2016.00087 https://doaj.org/article/aa8c515ecae848bc934c3b963bd83916 |
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ftdoajarticles:oai:doaj.org/article:aa8c515ecae848bc934c3b963bd83916 2023-05-15T16:21:21+02:00 Force balance along Isunnguata Sermia, west Greenland Toby Meierbachtol Joel Harper Jesse Johnson 2016-09-01T00:00:00Z https://doi.org/10.3389/feart.2016.00087 https://doaj.org/article/aa8c515ecae848bc934c3b963bd83916 EN eng Frontiers Media S.A. http://journal.frontiersin.org/Journal/10.3389/feart.2016.00087/full https://doaj.org/toc/2296-6463 2296-6463 doi:10.3389/feart.2016.00087 https://doaj.org/article/aa8c515ecae848bc934c3b963bd83916 Frontiers in Earth Science, Vol 4 (2016) Greenland ice sheet Force balance Ice sheet dynamics Driving stress Basal Processes Science Q article 2016 ftdoajarticles https://doi.org/10.3389/feart.2016.00087 2022-12-31T12:45:47Z Ice flows when gravity acts on gradients in surface elevation, producing driving stresses. In the Isunnguata Sermia and Russel Glacier catchments of western Greenland, a 50% decline in driving stress along a flow line is juxtaposed with increasing surface flow speed. Here, these circumstances are investigated using modern observational data sources and an analysis of the balance of forces. Stress gradients in the ice mass and basal drag which resist the local driving stress are computed in order to investigate the underlying processes influencing the velocity and stress regimes. Our results show that the largest resistive stress gradients along the flowline result from increasing surface velocity. However, the longitudinal coupling stresses fail to exceed 15 kPa, or 20% of the local driving stress. Consequently, computed basal drag declines in proportion to the driving stress. In the absence of significant resistive stress gradients, other mechanisms are therefore necessary to explain the observed velocity increase despite declining driving stress. In the study area, the observed velocity - driving stress feature occurs at the long-term mean position of the equilibrium line of surface mass balance. We hypothesize that this position approximates the inland limit where surface meltwater penetrates the bed, and that the increased surface velocity reflects enhanced basal motion associated with seasonal meltwater perturbations. Article in Journal/Newspaper glacier Greenland Ice Sheet Directory of Open Access Journals: DOAJ Articles Greenland Isunnguata Sermia ENVELOPE(-50.167,-50.167,67.183,67.183) Frontiers in Earth Science 4 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Greenland ice sheet Force balance Ice sheet dynamics Driving stress Basal Processes Science Q |
spellingShingle |
Greenland ice sheet Force balance Ice sheet dynamics Driving stress Basal Processes Science Q Toby Meierbachtol Joel Harper Jesse Johnson Force balance along Isunnguata Sermia, west Greenland |
topic_facet |
Greenland ice sheet Force balance Ice sheet dynamics Driving stress Basal Processes Science Q |
description |
Ice flows when gravity acts on gradients in surface elevation, producing driving stresses. In the Isunnguata Sermia and Russel Glacier catchments of western Greenland, a 50% decline in driving stress along a flow line is juxtaposed with increasing surface flow speed. Here, these circumstances are investigated using modern observational data sources and an analysis of the balance of forces. Stress gradients in the ice mass and basal drag which resist the local driving stress are computed in order to investigate the underlying processes influencing the velocity and stress regimes. Our results show that the largest resistive stress gradients along the flowline result from increasing surface velocity. However, the longitudinal coupling stresses fail to exceed 15 kPa, or 20% of the local driving stress. Consequently, computed basal drag declines in proportion to the driving stress. In the absence of significant resistive stress gradients, other mechanisms are therefore necessary to explain the observed velocity increase despite declining driving stress. In the study area, the observed velocity - driving stress feature occurs at the long-term mean position of the equilibrium line of surface mass balance. We hypothesize that this position approximates the inland limit where surface meltwater penetrates the bed, and that the increased surface velocity reflects enhanced basal motion associated with seasonal meltwater perturbations. |
format |
Article in Journal/Newspaper |
author |
Toby Meierbachtol Joel Harper Jesse Johnson |
author_facet |
Toby Meierbachtol Joel Harper Jesse Johnson |
author_sort |
Toby Meierbachtol |
title |
Force balance along Isunnguata Sermia, west Greenland |
title_short |
Force balance along Isunnguata Sermia, west Greenland |
title_full |
Force balance along Isunnguata Sermia, west Greenland |
title_fullStr |
Force balance along Isunnguata Sermia, west Greenland |
title_full_unstemmed |
Force balance along Isunnguata Sermia, west Greenland |
title_sort |
force balance along isunnguata sermia, west greenland |
publisher |
Frontiers Media S.A. |
publishDate |
2016 |
url |
https://doi.org/10.3389/feart.2016.00087 https://doaj.org/article/aa8c515ecae848bc934c3b963bd83916 |
long_lat |
ENVELOPE(-50.167,-50.167,67.183,67.183) |
geographic |
Greenland Isunnguata Sermia |
geographic_facet |
Greenland Isunnguata Sermia |
genre |
glacier Greenland Ice Sheet |
genre_facet |
glacier Greenland Ice Sheet |
op_source |
Frontiers in Earth Science, Vol 4 (2016) |
op_relation |
http://journal.frontiersin.org/Journal/10.3389/feart.2016.00087/full https://doaj.org/toc/2296-6463 2296-6463 doi:10.3389/feart.2016.00087 https://doaj.org/article/aa8c515ecae848bc934c3b963bd83916 |
op_doi |
https://doi.org/10.3389/feart.2016.00087 |
container_title |
Frontiers in Earth Science |
container_volume |
4 |
_version_ |
1766009362189385728 |