Sliding of temperate basal ice on a rough, hard bed: creep mechanisms, pressure melting, and implications for ice streaming
Basal ice motion is crucial to ice dynamics of ice sheets. The classic Weertman model for basal sliding over bedrock obstacles proposes that sliding velocity is controlled by pressure melting and/or ductile flow, whichever is the fastest; it further assumes that pressure melting is limited by heat f...
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2016
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00011486 2023-05-15T16:29:25+02:00 Sliding of temperate basal ice on a rough, hard bed: creep mechanisms, pressure melting, and implications for ice streaming Krabbendam, Maarten 2016-09 electronic https://doi.org/10.5194/tc-10-1915-2016 https://noa.gwlb.de/receive/cop_mods_00011486 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00011443/tc-10-1915-2016.pdf https://tc.copernicus.org/articles/10/1915/2016/tc-10-1915-2016.pdf eng eng Copernicus Publications The Cryosphere -- ˜Theœ Cryosphere -- http://www.bibliothek.uni-regensburg.de/ezeit/?2393169 -- http://www.the-cryosphere.net/ -- 1994-0424 https://doi.org/10.5194/tc-10-1915-2016 https://noa.gwlb.de/receive/cop_mods_00011486 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00011443/tc-10-1915-2016.pdf https://tc.copernicus.org/articles/10/1915/2016/tc-10-1915-2016.pdf uneingeschränkt info:eu-repo/semantics/openAccess article Verlagsveröffentlichung article Text doc-type:article 2016 ftnonlinearchiv https://doi.org/10.5194/tc-10-1915-2016 2022-02-08T22:56:31Z Basal ice motion is crucial to ice dynamics of ice sheets. The classic Weertman model for basal sliding over bedrock obstacles proposes that sliding velocity is controlled by pressure melting and/or ductile flow, whichever is the fastest; it further assumes that pressure melting is limited by heat flow through the obstacle and ductile flow is controlled by standard power-law creep. These last two assumptions, however, are not applicable if a substantial basal layer of temperate (T ∼ Tmelt) ice is present. In that case, frictional melting can produce excess basal meltwater and efficient water flow, leading to near-thermal equilibrium. High-temperature ice creep experiments have shown a sharp weakening of a factor 5–10 close to Tmelt, suggesting standard power-law creep does not operate due to a switch to melt-assisted creep with a possible component of grain boundary melting. Pressure melting is controlled by meltwater production, heat advection by flowing meltwater to the next obstacle and heat conduction through ice/rock over half the obstacle height. No heat flow through the obstacle is required. Ice streaming over a rough, hard bed, as possibly in the Northeast Greenland Ice Stream, may be explained by enhanced basal motion in a thick temperate ice layer. Article in Journal/Newspaper Greenland The Cryosphere Niedersächsisches Online-Archiv NOA Greenland Weertman ENVELOPE(-67.753,-67.753,-66.972,-66.972) The Cryosphere 10 5 1915 1932 |
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Niedersächsisches Online-Archiv NOA |
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English |
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article Verlagsveröffentlichung |
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article Verlagsveröffentlichung Krabbendam, Maarten Sliding of temperate basal ice on a rough, hard bed: creep mechanisms, pressure melting, and implications for ice streaming |
topic_facet |
article Verlagsveröffentlichung |
description |
Basal ice motion is crucial to ice dynamics of ice sheets. The classic Weertman model for basal sliding over bedrock obstacles proposes that sliding velocity is controlled by pressure melting and/or ductile flow, whichever is the fastest; it further assumes that pressure melting is limited by heat flow through the obstacle and ductile flow is controlled by standard power-law creep. These last two assumptions, however, are not applicable if a substantial basal layer of temperate (T ∼ Tmelt) ice is present. In that case, frictional melting can produce excess basal meltwater and efficient water flow, leading to near-thermal equilibrium. High-temperature ice creep experiments have shown a sharp weakening of a factor 5–10 close to Tmelt, suggesting standard power-law creep does not operate due to a switch to melt-assisted creep with a possible component of grain boundary melting. Pressure melting is controlled by meltwater production, heat advection by flowing meltwater to the next obstacle and heat conduction through ice/rock over half the obstacle height. No heat flow through the obstacle is required. Ice streaming over a rough, hard bed, as possibly in the Northeast Greenland Ice Stream, may be explained by enhanced basal motion in a thick temperate ice layer. |
format |
Article in Journal/Newspaper |
author |
Krabbendam, Maarten |
author_facet |
Krabbendam, Maarten |
author_sort |
Krabbendam, Maarten |
title |
Sliding of temperate basal ice on a rough, hard bed: creep mechanisms, pressure melting, and implications for ice streaming |
title_short |
Sliding of temperate basal ice on a rough, hard bed: creep mechanisms, pressure melting, and implications for ice streaming |
title_full |
Sliding of temperate basal ice on a rough, hard bed: creep mechanisms, pressure melting, and implications for ice streaming |
title_fullStr |
Sliding of temperate basal ice on a rough, hard bed: creep mechanisms, pressure melting, and implications for ice streaming |
title_full_unstemmed |
Sliding of temperate basal ice on a rough, hard bed: creep mechanisms, pressure melting, and implications for ice streaming |
title_sort |
sliding of temperate basal ice on a rough, hard bed: creep mechanisms, pressure melting, and implications for ice streaming |
publisher |
Copernicus Publications |
publishDate |
2016 |
url |
https://doi.org/10.5194/tc-10-1915-2016 https://noa.gwlb.de/receive/cop_mods_00011486 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00011443/tc-10-1915-2016.pdf https://tc.copernicus.org/articles/10/1915/2016/tc-10-1915-2016.pdf |
long_lat |
ENVELOPE(-67.753,-67.753,-66.972,-66.972) |
geographic |
Greenland Weertman |
geographic_facet |
Greenland Weertman |
genre |
Greenland The Cryosphere |
genre_facet |
Greenland The Cryosphere |
op_relation |
The Cryosphere -- ˜Theœ Cryosphere -- http://www.bibliothek.uni-regensburg.de/ezeit/?2393169 -- http://www.the-cryosphere.net/ -- 1994-0424 https://doi.org/10.5194/tc-10-1915-2016 https://noa.gwlb.de/receive/cop_mods_00011486 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00011443/tc-10-1915-2016.pdf https://tc.copernicus.org/articles/10/1915/2016/tc-10-1915-2016.pdf |
op_rights |
uneingeschränkt info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/tc-10-1915-2016 |
container_title |
The Cryosphere |
container_volume |
10 |
container_issue |
5 |
container_start_page |
1915 |
op_container_end_page |
1932 |
_version_ |
1766019119406120960 |