Terminus dynamics at an advancing glacier: Taku Glacier, Alaska
ABSTRACT. Taku Glacier, Alaska, USA, is currently in the advance stage of the tidewater glacier cycle. We investigated the near-terminus dynamics by measuring surface velocities, surface elevation changes, ice thickness and ablation. Velocities vary on sub-daily, diurnal, seasonal and interannual ti...
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ftciteseerx:oai:CiteSeerX.psu:10.1.1.634.5738 2023-05-15T16:20:19+02:00 Terminus dynamics at an advancing glacier: Taku Glacier, Alaska Matt A. King The Pennsylvania State University CiteSeerX Archives application/pdf http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.634.5738 http://www.igsoc.org/journal/55/194/j09j006.pdf en eng http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.634.5738 http://www.igsoc.org/journal/55/194/j09j006.pdf Metadata may be used without restrictions as long as the oai identifier remains attached to it. http://www.igsoc.org/journal/55/194/j09j006.pdf text ftciteseerx 2016-01-08T15:38:17Z ABSTRACT. Taku Glacier, Alaska, USA, is currently in the advance stage of the tidewater glacier cycle. We investigated the near-terminus dynamics by measuring surface velocities, surface elevation changes, ice thickness and ablation. Velocities vary on sub-daily, diurnal, seasonal and interannual timescales. Flowline modeling shows that the modeled surface velocities are sensitive to changes in till yield strength and thus effective basal pressures. The glacier bed deepens in the up-glacier direction and this imposes a minimum subglacial water pressure necessary for water to drain along the bed. In a simple model we impose water-pressure gradients based on phreatic surfaces of constant slopes to simulate the winter– summer transitions. This proves sufficient to explain an observed early-season switch from compressional to block flow. Velocities also vary between years. Changing basal conditions can result in lower horizontal velocities, which decrease the ice supply to the terminus and result in temporary surface lowering. But a decrease in ice flux to the terminus must lead to ice storage further upstream, and that ice mass will eventually reach the terminus. This can explain the observed episodic nature of terminus advance. 1. Text glacier Tidewater Alaska Unknown Taku ENVELOPE(-133.854,-133.854,59.633,59.633) |
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Open Polar |
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Unknown |
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ftciteseerx |
language |
English |
description |
ABSTRACT. Taku Glacier, Alaska, USA, is currently in the advance stage of the tidewater glacier cycle. We investigated the near-terminus dynamics by measuring surface velocities, surface elevation changes, ice thickness and ablation. Velocities vary on sub-daily, diurnal, seasonal and interannual timescales. Flowline modeling shows that the modeled surface velocities are sensitive to changes in till yield strength and thus effective basal pressures. The glacier bed deepens in the up-glacier direction and this imposes a minimum subglacial water pressure necessary for water to drain along the bed. In a simple model we impose water-pressure gradients based on phreatic surfaces of constant slopes to simulate the winter– summer transitions. This proves sufficient to explain an observed early-season switch from compressional to block flow. Velocities also vary between years. Changing basal conditions can result in lower horizontal velocities, which decrease the ice supply to the terminus and result in temporary surface lowering. But a decrease in ice flux to the terminus must lead to ice storage further upstream, and that ice mass will eventually reach the terminus. This can explain the observed episodic nature of terminus advance. 1. |
author2 |
The Pennsylvania State University CiteSeerX Archives |
format |
Text |
author |
Matt A. King |
spellingShingle |
Matt A. King Terminus dynamics at an advancing glacier: Taku Glacier, Alaska |
author_facet |
Matt A. King |
author_sort |
Matt A. King |
title |
Terminus dynamics at an advancing glacier: Taku Glacier, Alaska |
title_short |
Terminus dynamics at an advancing glacier: Taku Glacier, Alaska |
title_full |
Terminus dynamics at an advancing glacier: Taku Glacier, Alaska |
title_fullStr |
Terminus dynamics at an advancing glacier: Taku Glacier, Alaska |
title_full_unstemmed |
Terminus dynamics at an advancing glacier: Taku Glacier, Alaska |
title_sort |
terminus dynamics at an advancing glacier: taku glacier, alaska |
url |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.634.5738 http://www.igsoc.org/journal/55/194/j09j006.pdf |
long_lat |
ENVELOPE(-133.854,-133.854,59.633,59.633) |
geographic |
Taku |
geographic_facet |
Taku |
genre |
glacier Tidewater Alaska |
genre_facet |
glacier Tidewater Alaska |
op_source |
http://www.igsoc.org/journal/55/194/j09j006.pdf |
op_relation |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.634.5738 http://www.igsoc.org/journal/55/194/j09j006.pdf |
op_rights |
Metadata may be used without restrictions as long as the oai identifier remains attached to it. |
_version_ |
1766008230622789632 |