Basal shear stress under alpine glaciers: insights from experiments using the iSOSIA and Elmer/Ice models
Shear stress at the base of glaciers exerts a significant control on basal sliding and hence also glacial erosion in arctic and high-altitude areas. However, the inaccessible nature of glacial beds complicates empirical studies of basal shear stress, and little is therefore known of its spatial and...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2016-02-01
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| Series: | Earth Surface Dynamics |
| Online Access: | http://www.earth-surf-dynam.net/4/159/2016/esurf-4-159-2016.pdf |
| _version_ | 1811338745805275136 |
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| author | C. F. Brædstrup D. L. Egholm S. V. Ugelvig V. K. Pedersen |
| author_facet | C. F. Brædstrup D. L. Egholm S. V. Ugelvig V. K. Pedersen |
| author_sort | C. F. Brædstrup |
| collection | DOAJ |
| description | Shear stress at the base of glaciers exerts a significant control on
basal sliding and hence also glacial erosion in arctic and high-altitude areas. However, the inaccessible nature of glacial beds complicates empirical studies of basal shear stress, and little is therefore known of its spatial and
temporal distribution.
<br><br>
In this study we seek to improve our understanding of basal shear stress
using a higher-order numerical ice model (iSOSIA). In order to test the
validity of the higher-order model, we first compare the detailed
distribution of basal shear stress in iSOSIA and in a three-dimensional
full-Stokes model (Elmer/Ice). We find that iSOSIA and Elmer/Ice predict similar first-order stress and velocity patterns, and that differences are restricted to local variations at length scales of the order of the grid resolution. In addition, we find that subglacial shear stress is relatively uniform and insensitive to subtle changes in local topographic relief.
<br><br>
Following the initial comparison studies, we use iSOSIA to investigate changes in basal shear stress as a result of landscape evolution by glacial erosion. The experiments with landscape evolution show that subglacial shear stress decreases as glacial erosion transforms preglacial V-shaped valleys into U-shaped troughs. These findings support the hypothesis that glacial erosion
is most efficient in the early stages of glacial landscape development. |
| first_indexed | 2024-04-13T18:15:42Z |
| format | Article |
| id | doaj.art-01b673e3e5c147d883492fa4e3777d62 |
| institution | Directory Open Access Journal |
| issn | 2196-6311 2196-632X |
| language | English |
| last_indexed | 2024-04-13T18:15:42Z |
| publishDate | 2016-02-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Earth Surface Dynamics |
| spelling | doaj.art-01b673e3e5c147d883492fa4e3777d622022-12-22T02:35:41ZengCopernicus PublicationsEarth Surface Dynamics2196-63112196-632X2016-02-014115917410.5194/esurf-4-159-2016Basal shear stress under alpine glaciers: insights from experiments using the iSOSIA and Elmer/Ice modelsC. F. Brædstrup0D. L. Egholm1S. V. Ugelvig2V. K. Pedersen3Department of Geoscience, Aarhus University, Høegh-Guldbergs gade 2, 8000 Aarhus, DenmarkDepartment of Geoscience, Aarhus University, Høegh-Guldbergs gade 2, 8000 Aarhus, DenmarkDepartment of Geoscience, Aarhus University, Høegh-Guldbergs gade 2, 8000 Aarhus, DenmarkDepartment of Earth Sciences, University of Bergen, Allégaten 41, 5007 Bergen, NorwayShear stress at the base of glaciers exerts a significant control on basal sliding and hence also glacial erosion in arctic and high-altitude areas. However, the inaccessible nature of glacial beds complicates empirical studies of basal shear stress, and little is therefore known of its spatial and temporal distribution. <br><br> In this study we seek to improve our understanding of basal shear stress using a higher-order numerical ice model (iSOSIA). In order to test the validity of the higher-order model, we first compare the detailed distribution of basal shear stress in iSOSIA and in a three-dimensional full-Stokes model (Elmer/Ice). We find that iSOSIA and Elmer/Ice predict similar first-order stress and velocity patterns, and that differences are restricted to local variations at length scales of the order of the grid resolution. In addition, we find that subglacial shear stress is relatively uniform and insensitive to subtle changes in local topographic relief. <br><br> Following the initial comparison studies, we use iSOSIA to investigate changes in basal shear stress as a result of landscape evolution by glacial erosion. The experiments with landscape evolution show that subglacial shear stress decreases as glacial erosion transforms preglacial V-shaped valleys into U-shaped troughs. These findings support the hypothesis that glacial erosion is most efficient in the early stages of glacial landscape development.http://www.earth-surf-dynam.net/4/159/2016/esurf-4-159-2016.pdf |
| spellingShingle | C. F. Brædstrup D. L. Egholm S. V. Ugelvig V. K. Pedersen Basal shear stress under alpine glaciers: insights from experiments using the iSOSIA and Elmer/Ice models Earth Surface Dynamics |
| title | Basal shear stress under alpine glaciers: insights from experiments using the iSOSIA and Elmer/Ice models |
| title_full | Basal shear stress under alpine glaciers: insights from experiments using the iSOSIA and Elmer/Ice models |
| title_fullStr | Basal shear stress under alpine glaciers: insights from experiments using the iSOSIA and Elmer/Ice models |
| title_full_unstemmed | Basal shear stress under alpine glaciers: insights from experiments using the iSOSIA and Elmer/Ice models |
| title_short | Basal shear stress under alpine glaciers: insights from experiments using the iSOSIA and Elmer/Ice models |
| title_sort | basal shear stress under alpine glaciers insights from experiments using the isosia and elmer ice models |
| url | http://www.earth-surf-dynam.net/4/159/2016/esurf-4-159-2016.pdf |
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