Influence of anisotropy on velocity and age distribution at Scharffenbergbotnen blue ice area
We use a full-Stokes thermo-mechanically coupled ice-flow model to study the dynamics of the glacier inside Scharffenbergbotnen valley, Dronning Maud Land, Antarctica. The domain encompasses a high accumulation rate region and, downstream, a sublimation-dominated bare ice ablation area. The ablation...
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Copernicus Publications
2014
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Online Access: | https://doi.org/10.5194/tc-8-607-2014 http://www.the-cryosphere.net/8/607/2014/tc-8-607-2014.pdf https://doaj.org/article/f2992e5ef77046439f941f52f9864912 |
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fttriple:oai:gotriple.eu:oai:doaj.org/article:f2992e5ef77046439f941f52f9864912 2023-05-15T14:00:45+02:00 Influence of anisotropy on velocity and age distribution at Scharffenbergbotnen blue ice area T. Zwinger M. Schäfer C. Martín J. C. Moore 2014-04-01 https://doi.org/10.5194/tc-8-607-2014 http://www.the-cryosphere.net/8/607/2014/tc-8-607-2014.pdf https://doaj.org/article/f2992e5ef77046439f941f52f9864912 en eng Copernicus Publications 1994-0416 1994-0424 doi:10.5194/tc-8-607-2014 http://www.the-cryosphere.net/8/607/2014/tc-8-607-2014.pdf https://doaj.org/article/f2992e5ef77046439f941f52f9864912 undefined The Cryosphere, Vol 8, Iss 2, Pp 607-621 (2014) geo envir Journal Article https://vocabularies.coar-repositories.org/resource_types/c_6501/ 2014 fttriple https://doi.org/10.5194/tc-8-607-2014 2023-01-22T17:49:54Z We use a full-Stokes thermo-mechanically coupled ice-flow model to study the dynamics of the glacier inside Scharffenbergbotnen valley, Dronning Maud Land, Antarctica. The domain encompasses a high accumulation rate region and, downstream, a sublimation-dominated bare ice ablation area. The ablation ice area is notable for having old ice at its surface since the vertical velocity is upwards, and horizontal velocities are almost stagnant there. We compare the model simulation with field observations of velocities and the age distribution of the surface ice. No satisfactory match using an isotropic flow law could be found because of too high vertical velocities and much too high horizontal ones in simulations despite varying enhancement factor, geothermal heat flux and surface temperatures over large ranges. However, the existence of a pronounced ice fabric may explain the observed present-day surface velocity and mass balance distribution in the inner Scharffenbergbotnen blue ice area. Near absence of data on the temporal evolution of Scharffenbergbotnen since the Late Glacial Maximum necessitates exploration of the impact of anisotropy using prescribed ice fabrics: isotropic, single maximum, and linear variation with depth, in both two-dimensional and three-dimensional flow models. The realistic velocity field simulated with a noncollinear orthotropic flow law, however, produced surface ages in significant disagreement with the few reliable age measurements and suggests that the age field is not in a steady state and that the present distribution is a result of a flow reorganization at about 15 000 yr BP. In order to fully understand the surface age distribution, a transient simulation starting from the Late Glacial Maximum including the correct initial conditions for geometry, age, fabric and temperature distribution would be needed. This is the first time that the importance of anisotropy has been demonstrated in the ice dynamics of a blue ice area and demonstrates the need to understand ice flow in order to ... Article in Journal/Newspaper Antarc* Antarctica Dronning Maud Land The Cryosphere Unknown Dronning Maud Land Scharffenbergbotnen ENVELOPE(-11.092,-11.092,-74.575,-74.575) The Cryosphere 8 2 607 621 |
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Open Polar |
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op_collection_id |
fttriple |
language |
English |
topic |
geo envir |
spellingShingle |
geo envir T. Zwinger M. Schäfer C. Martín J. C. Moore Influence of anisotropy on velocity and age distribution at Scharffenbergbotnen blue ice area |
topic_facet |
geo envir |
description |
We use a full-Stokes thermo-mechanically coupled ice-flow model to study the dynamics of the glacier inside Scharffenbergbotnen valley, Dronning Maud Land, Antarctica. The domain encompasses a high accumulation rate region and, downstream, a sublimation-dominated bare ice ablation area. The ablation ice area is notable for having old ice at its surface since the vertical velocity is upwards, and horizontal velocities are almost stagnant there. We compare the model simulation with field observations of velocities and the age distribution of the surface ice. No satisfactory match using an isotropic flow law could be found because of too high vertical velocities and much too high horizontal ones in simulations despite varying enhancement factor, geothermal heat flux and surface temperatures over large ranges. However, the existence of a pronounced ice fabric may explain the observed present-day surface velocity and mass balance distribution in the inner Scharffenbergbotnen blue ice area. Near absence of data on the temporal evolution of Scharffenbergbotnen since the Late Glacial Maximum necessitates exploration of the impact of anisotropy using prescribed ice fabrics: isotropic, single maximum, and linear variation with depth, in both two-dimensional and three-dimensional flow models. The realistic velocity field simulated with a noncollinear orthotropic flow law, however, produced surface ages in significant disagreement with the few reliable age measurements and suggests that the age field is not in a steady state and that the present distribution is a result of a flow reorganization at about 15 000 yr BP. In order to fully understand the surface age distribution, a transient simulation starting from the Late Glacial Maximum including the correct initial conditions for geometry, age, fabric and temperature distribution would be needed. This is the first time that the importance of anisotropy has been demonstrated in the ice dynamics of a blue ice area and demonstrates the need to understand ice flow in order to ... |
format |
Article in Journal/Newspaper |
author |
T. Zwinger M. Schäfer C. Martín J. C. Moore |
author_facet |
T. Zwinger M. Schäfer C. Martín J. C. Moore |
author_sort |
T. Zwinger |
title |
Influence of anisotropy on velocity and age distribution at Scharffenbergbotnen blue ice area |
title_short |
Influence of anisotropy on velocity and age distribution at Scharffenbergbotnen blue ice area |
title_full |
Influence of anisotropy on velocity and age distribution at Scharffenbergbotnen blue ice area |
title_fullStr |
Influence of anisotropy on velocity and age distribution at Scharffenbergbotnen blue ice area |
title_full_unstemmed |
Influence of anisotropy on velocity and age distribution at Scharffenbergbotnen blue ice area |
title_sort |
influence of anisotropy on velocity and age distribution at scharffenbergbotnen blue ice area |
publisher |
Copernicus Publications |
publishDate |
2014 |
url |
https://doi.org/10.5194/tc-8-607-2014 http://www.the-cryosphere.net/8/607/2014/tc-8-607-2014.pdf https://doaj.org/article/f2992e5ef77046439f941f52f9864912 |
long_lat |
ENVELOPE(-11.092,-11.092,-74.575,-74.575) |
geographic |
Dronning Maud Land Scharffenbergbotnen |
geographic_facet |
Dronning Maud Land Scharffenbergbotnen |
genre |
Antarc* Antarctica Dronning Maud Land The Cryosphere |
genre_facet |
Antarc* Antarctica Dronning Maud Land The Cryosphere |
op_source |
The Cryosphere, Vol 8, Iss 2, Pp 607-621 (2014) |
op_relation |
1994-0416 1994-0424 doi:10.5194/tc-8-607-2014 http://www.the-cryosphere.net/8/607/2014/tc-8-607-2014.pdf https://doaj.org/article/f2992e5ef77046439f941f52f9864912 |
op_rights |
undefined |
op_doi |
https://doi.org/10.5194/tc-8-607-2014 |
container_title |
The Cryosphere |
container_volume |
8 |
container_issue |
2 |
container_start_page |
607 |
op_container_end_page |
621 |
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1766270097501978624 |