Sensitivity of basal conditions in an inverse model: Vestfonna ice cap, Nordaustlandet/Svalbard
The dynamics of Vestfonna ice cap (Svalbard) are dominated by fast-flowing outlet glaciers. Its mass balance is poorly known and affected dynamically by these fast-flowing outlet glaciers. Hence, it is a challenging target for ice flow modeling. Precise knowledge of the basal conditions and implemen...
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Online Access: | https://doi.org/10.5194/tc-6-771-2012 https://tc.copernicus.org/articles/6/771/2012/ |
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ftcopernicus:oai:publications.copernicus.org:tc13944 2023-05-15T16:22:15+02:00 Sensitivity of basal conditions in an inverse model: Vestfonna ice cap, Nordaustlandet/Svalbard Schäfer, M. Zwinger, T. Christoffersen, P. Gillet-Chaulet, F. Laakso, K. Pettersson, R. Pohjola, V. A. Strozzi, T. Moore, J. C. 2018-09-27 application/pdf https://doi.org/10.5194/tc-6-771-2012 https://tc.copernicus.org/articles/6/771/2012/ eng eng doi:10.5194/tc-6-771-2012 https://tc.copernicus.org/articles/6/771/2012/ eISSN: 1994-0424 Text 2018 ftcopernicus https://doi.org/10.5194/tc-6-771-2012 2020-07-20T16:25:46Z The dynamics of Vestfonna ice cap (Svalbard) are dominated by fast-flowing outlet glaciers. Its mass balance is poorly known and affected dynamically by these fast-flowing outlet glaciers. Hence, it is a challenging target for ice flow modeling. Precise knowledge of the basal conditions and implementation of a good sliding law are crucial for the modeling of this ice cap. Here we use the full-Stokes finite element code Elmer/Ice to model the 3-D flow over the whole ice cap. We use a Robin inverse method to infer the basal friction from the surface velocities observed in 1995. Our results illustrate the importance of the basal friction parameter in reproducing observed velocity fields. We also show the importance of having variable basal friction as given by the inverse method to reproduce the velocity fields of each outlet glacier – a simple parametrization of basal friction cannot give realistic velocities in a forward model. We study the robustness and sensitivity of this method with respect to different parameters (mesh characteristics, ice temperature, errors in topographic and velocity data). The uncertainty in the observational parameters and input data proved to be sufficiently small as not to adversely affect the fidelity of the model. Text glacier Ice cap Nordaustlandet Svalbard Vestfonna Copernicus Publications: E-Journals Nordaustlandet ENVELOPE(22.400,22.400,79.800,79.800) Svalbard Vestfonna ENVELOPE(20.761,20.761,79.941,79.941) The Cryosphere 6 4 771 783 |
institution |
Open Polar |
collection |
Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
The dynamics of Vestfonna ice cap (Svalbard) are dominated by fast-flowing outlet glaciers. Its mass balance is poorly known and affected dynamically by these fast-flowing outlet glaciers. Hence, it is a challenging target for ice flow modeling. Precise knowledge of the basal conditions and implementation of a good sliding law are crucial for the modeling of this ice cap. Here we use the full-Stokes finite element code Elmer/Ice to model the 3-D flow over the whole ice cap. We use a Robin inverse method to infer the basal friction from the surface velocities observed in 1995. Our results illustrate the importance of the basal friction parameter in reproducing observed velocity fields. We also show the importance of having variable basal friction as given by the inverse method to reproduce the velocity fields of each outlet glacier – a simple parametrization of basal friction cannot give realistic velocities in a forward model. We study the robustness and sensitivity of this method with respect to different parameters (mesh characteristics, ice temperature, errors in topographic and velocity data). The uncertainty in the observational parameters and input data proved to be sufficiently small as not to adversely affect the fidelity of the model. |
format |
Text |
author |
Schäfer, M. Zwinger, T. Christoffersen, P. Gillet-Chaulet, F. Laakso, K. Pettersson, R. Pohjola, V. A. Strozzi, T. Moore, J. C. |
spellingShingle |
Schäfer, M. Zwinger, T. Christoffersen, P. Gillet-Chaulet, F. Laakso, K. Pettersson, R. Pohjola, V. A. Strozzi, T. Moore, J. C. Sensitivity of basal conditions in an inverse model: Vestfonna ice cap, Nordaustlandet/Svalbard |
author_facet |
Schäfer, M. Zwinger, T. Christoffersen, P. Gillet-Chaulet, F. Laakso, K. Pettersson, R. Pohjola, V. A. Strozzi, T. Moore, J. C. |
author_sort |
Schäfer, M. |
title |
Sensitivity of basal conditions in an inverse model: Vestfonna ice cap, Nordaustlandet/Svalbard |
title_short |
Sensitivity of basal conditions in an inverse model: Vestfonna ice cap, Nordaustlandet/Svalbard |
title_full |
Sensitivity of basal conditions in an inverse model: Vestfonna ice cap, Nordaustlandet/Svalbard |
title_fullStr |
Sensitivity of basal conditions in an inverse model: Vestfonna ice cap, Nordaustlandet/Svalbard |
title_full_unstemmed |
Sensitivity of basal conditions in an inverse model: Vestfonna ice cap, Nordaustlandet/Svalbard |
title_sort |
sensitivity of basal conditions in an inverse model: vestfonna ice cap, nordaustlandet/svalbard |
publishDate |
2018 |
url |
https://doi.org/10.5194/tc-6-771-2012 https://tc.copernicus.org/articles/6/771/2012/ |
long_lat |
ENVELOPE(22.400,22.400,79.800,79.800) ENVELOPE(20.761,20.761,79.941,79.941) |
geographic |
Nordaustlandet Svalbard Vestfonna |
geographic_facet |
Nordaustlandet Svalbard Vestfonna |
genre |
glacier Ice cap Nordaustlandet Svalbard Vestfonna |
genre_facet |
glacier Ice cap Nordaustlandet Svalbard Vestfonna |
op_source |
eISSN: 1994-0424 |
op_relation |
doi:10.5194/tc-6-771-2012 https://tc.copernicus.org/articles/6/771/2012/ |
op_doi |
https://doi.org/10.5194/tc-6-771-2012 |
container_title |
The Cryosphere |
container_volume |
6 |
container_issue |
4 |
container_start_page |
771 |
op_container_end_page |
783 |
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1766010216263974912 |