Numerical investigation of the effects of temporal variations in basal lubrication on englacial strain-rate distribution
The effects of spatial and temporal variations in basal lubrication on the englacial strain rate and surface velocity distribution are investigated with a numerical ice-flow model. General aspects of the solutions are compared to measurements made on Lauteraargletscher, Switzerland, in 2001, that sh...
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International Glaciological Society
2003
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ftnerc:oai:nora.nerc.ac.uk:12984 2023-05-15T13:29:40+02:00 Numerical investigation of the effects of temporal variations in basal lubrication on englacial strain-rate distribution Sugiyama, Shin Gudmundsson, G. Hilmar Helbing, Jakob 2003 http://nora.nerc.ac.uk/id/eprint/12984/ http://www.ingentaconnect.com/content/igsoc/agl/2003/00000037/00000001/art00008 unknown International Glaciological Society Sugiyama, Shin; Gudmundsson, G. Hilmar orcid:0000-0003-4236-5369 Helbing, Jakob. 2003 Numerical investigation of the effects of temporal variations in basal lubrication on englacial strain-rate distribution. Annals of Glaciology, 37 (1). 49-54. https://doi.org/10.3189/172756403781815618 <https://doi.org/10.3189/172756403781815618> Glaciology Publication - Article PeerReviewed 2003 ftnerc https://doi.org/10.3189/172756403781815618 2023-02-04T19:28:22Z The effects of spatial and temporal variations in basal lubrication on the englacial strain rate and surface velocity distribution are investigated with a numerical ice-flow model. General aspects of the solutions are compared to measurements made on Lauteraargletscher, Switzerland, in 2001, that showed diurnal fluctuations in both surface velocity and englacial vertical strain. We find that spatial gradients in basal lubrication can set up variations in the deviatoric stress field that increases with distance to the bed and has a maximum value near the glacier surface. This stress field produces a significant strain rate near the surface. The temporal evolution of a slippery zone is identified as a possible cause of the observed diurnal variations in the vertical strain rate. Although general aspects of the measurements can be explained in this way, the calculated vertical strain rates are too small, suggesting that the modeled effective viscosity values using Glen's flow law are too large near the surface. Article in Journal/Newspaper Annals of Glaciology Natural Environment Research Council: NERC Open Research Archive Annals of Glaciology 37 49 54 |
institution |
Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
unknown |
topic |
Glaciology |
spellingShingle |
Glaciology Sugiyama, Shin Gudmundsson, G. Hilmar Helbing, Jakob Numerical investigation of the effects of temporal variations in basal lubrication on englacial strain-rate distribution |
topic_facet |
Glaciology |
description |
The effects of spatial and temporal variations in basal lubrication on the englacial strain rate and surface velocity distribution are investigated with a numerical ice-flow model. General aspects of the solutions are compared to measurements made on Lauteraargletscher, Switzerland, in 2001, that showed diurnal fluctuations in both surface velocity and englacial vertical strain. We find that spatial gradients in basal lubrication can set up variations in the deviatoric stress field that increases with distance to the bed and has a maximum value near the glacier surface. This stress field produces a significant strain rate near the surface. The temporal evolution of a slippery zone is identified as a possible cause of the observed diurnal variations in the vertical strain rate. Although general aspects of the measurements can be explained in this way, the calculated vertical strain rates are too small, suggesting that the modeled effective viscosity values using Glen's flow law are too large near the surface. |
format |
Article in Journal/Newspaper |
author |
Sugiyama, Shin Gudmundsson, G. Hilmar Helbing, Jakob |
author_facet |
Sugiyama, Shin Gudmundsson, G. Hilmar Helbing, Jakob |
author_sort |
Sugiyama, Shin |
title |
Numerical investigation of the effects of temporal variations in basal lubrication on englacial strain-rate distribution |
title_short |
Numerical investigation of the effects of temporal variations in basal lubrication on englacial strain-rate distribution |
title_full |
Numerical investigation of the effects of temporal variations in basal lubrication on englacial strain-rate distribution |
title_fullStr |
Numerical investigation of the effects of temporal variations in basal lubrication on englacial strain-rate distribution |
title_full_unstemmed |
Numerical investigation of the effects of temporal variations in basal lubrication on englacial strain-rate distribution |
title_sort |
numerical investigation of the effects of temporal variations in basal lubrication on englacial strain-rate distribution |
publisher |
International Glaciological Society |
publishDate |
2003 |
url |
http://nora.nerc.ac.uk/id/eprint/12984/ http://www.ingentaconnect.com/content/igsoc/agl/2003/00000037/00000001/art00008 |
genre |
Annals of Glaciology |
genre_facet |
Annals of Glaciology |
op_relation |
Sugiyama, Shin; Gudmundsson, G. Hilmar orcid:0000-0003-4236-5369 Helbing, Jakob. 2003 Numerical investigation of the effects of temporal variations in basal lubrication on englacial strain-rate distribution. Annals of Glaciology, 37 (1). 49-54. https://doi.org/10.3189/172756403781815618 <https://doi.org/10.3189/172756403781815618> |
op_doi |
https://doi.org/10.3189/172756403781815618 |
container_title |
Annals of Glaciology |
container_volume |
37 |
container_start_page |
49 |
op_container_end_page |
54 |
_version_ |
1766001839104327680 |