Modelled glacier dynamics over the last quarter of a century at Jakobshavn Isbræ
Observations over the past 2 decades show substantial ice loss associated with the speed-up of marine-terminating glaciers in Greenland. Here we use a regional three-dimensional outlet glacier model to simulate the behaviour of Jakobshavn Isbræ (JI) located in western Greenland. Our approach is to m...
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2016
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ftdoajarticles:oai:doaj.org/article:fdbf6c5720aa4af6adcda018b8099543 2023-05-15T16:21:22+02:00 Modelled glacier dynamics over the last quarter of a century at Jakobshavn Isbræ I. S. Muresan S. A. Khan A. Aschwanden C. Khroulev T. Van Dam J. Bamber M. R. van den Broeke B. Wouters P. Kuipers Munneke K. H. Kjær 2016-03-01T00:00:00Z https://doi.org/10.5194/tc-10-597-2016 https://doaj.org/article/fdbf6c5720aa4af6adcda018b8099543 EN eng Copernicus Publications http://www.the-cryosphere.net/10/597/2016/tc-10-597-2016.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 1994-0416 1994-0424 doi:10.5194/tc-10-597-2016 https://doaj.org/article/fdbf6c5720aa4af6adcda018b8099543 The Cryosphere, Vol 10, Iss 2, Pp 597-611 (2016) Environmental sciences GE1-350 Geology QE1-996.5 article 2016 ftdoajarticles https://doi.org/10.5194/tc-10-597-2016 2022-12-31T14:28:24Z Observations over the past 2 decades show substantial ice loss associated with the speed-up of marine-terminating glaciers in Greenland. Here we use a regional three-dimensional outlet glacier model to simulate the behaviour of Jakobshavn Isbræ (JI) located in western Greenland. Our approach is to model and understand the recent behaviour of JI with a physical process-based model. Using atmospheric forcing and an ocean parametrization we tune our model to reproduce observed frontal changes of JI during 1990–2014. In our simulations, most of the JI retreat during 1990–2014 is driven by the ocean parametrization used and the glacier's subsequent response, which is largely governed by bed geometry. In general, the study shows significant progress in modelling the temporal variability of the flow at JI. Our results suggest that the overall variability in modelled horizontal velocities is a response to variations in terminus position. The model simulates two major accelerations that are consistent with observations of changes in glacier terminus. The first event occurred in 1998 and was triggered by a retreat of the front and moderate thinning of JI prior to 1998. The second event, which started in 2003 and peaked in the summer 2004, was triggered by the final break-up of the floating tongue. This break-up reduced the buttressing at the JI terminus that resulted in further thinning. As the terminus retreated over a reverse bed slope into deeper water, sustained high velocities over the last decade have been observed at JI. Our model provides evidence that the 1998 and 2003 flow accelerations are most likely initiated by the ocean parametrization used but JI's subsequent dynamic response was governed by its own bed geometry. We are unable to reproduce the observed 2010–2012 terminus retreat in our simulations. We attribute this limitation to either inaccuracies in basal topography or to misrepresentations of the climatic forcings that were applied. Nevertheless, the model is able to simulate the previously observed ... Article in Journal/Newspaper glacier Greenland Jakobshavn Jakobshavn isbræ The Cryosphere Directory of Open Access Journals: DOAJ Articles Greenland Jakobshavn Isbræ ENVELOPE(-49.917,-49.917,69.167,69.167) The Cryosphere 10 2 597 611 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Environmental sciences GE1-350 Geology QE1-996.5 |
spellingShingle |
Environmental sciences GE1-350 Geology QE1-996.5 I. S. Muresan S. A. Khan A. Aschwanden C. Khroulev T. Van Dam J. Bamber M. R. van den Broeke B. Wouters P. Kuipers Munneke K. H. Kjær Modelled glacier dynamics over the last quarter of a century at Jakobshavn Isbræ |
topic_facet |
Environmental sciences GE1-350 Geology QE1-996.5 |
description |
Observations over the past 2 decades show substantial ice loss associated with the speed-up of marine-terminating glaciers in Greenland. Here we use a regional three-dimensional outlet glacier model to simulate the behaviour of Jakobshavn Isbræ (JI) located in western Greenland. Our approach is to model and understand the recent behaviour of JI with a physical process-based model. Using atmospheric forcing and an ocean parametrization we tune our model to reproduce observed frontal changes of JI during 1990–2014. In our simulations, most of the JI retreat during 1990–2014 is driven by the ocean parametrization used and the glacier's subsequent response, which is largely governed by bed geometry. In general, the study shows significant progress in modelling the temporal variability of the flow at JI. Our results suggest that the overall variability in modelled horizontal velocities is a response to variations in terminus position. The model simulates two major accelerations that are consistent with observations of changes in glacier terminus. The first event occurred in 1998 and was triggered by a retreat of the front and moderate thinning of JI prior to 1998. The second event, which started in 2003 and peaked in the summer 2004, was triggered by the final break-up of the floating tongue. This break-up reduced the buttressing at the JI terminus that resulted in further thinning. As the terminus retreated over a reverse bed slope into deeper water, sustained high velocities over the last decade have been observed at JI. Our model provides evidence that the 1998 and 2003 flow accelerations are most likely initiated by the ocean parametrization used but JI's subsequent dynamic response was governed by its own bed geometry. We are unable to reproduce the observed 2010–2012 terminus retreat in our simulations. We attribute this limitation to either inaccuracies in basal topography or to misrepresentations of the climatic forcings that were applied. Nevertheless, the model is able to simulate the previously observed ... |
format |
Article in Journal/Newspaper |
author |
I. S. Muresan S. A. Khan A. Aschwanden C. Khroulev T. Van Dam J. Bamber M. R. van den Broeke B. Wouters P. Kuipers Munneke K. H. Kjær |
author_facet |
I. S. Muresan S. A. Khan A. Aschwanden C. Khroulev T. Van Dam J. Bamber M. R. van den Broeke B. Wouters P. Kuipers Munneke K. H. Kjær |
author_sort |
I. S. Muresan |
title |
Modelled glacier dynamics over the last quarter of a century at Jakobshavn Isbræ |
title_short |
Modelled glacier dynamics over the last quarter of a century at Jakobshavn Isbræ |
title_full |
Modelled glacier dynamics over the last quarter of a century at Jakobshavn Isbræ |
title_fullStr |
Modelled glacier dynamics over the last quarter of a century at Jakobshavn Isbræ |
title_full_unstemmed |
Modelled glacier dynamics over the last quarter of a century at Jakobshavn Isbræ |
title_sort |
modelled glacier dynamics over the last quarter of a century at jakobshavn isbræ |
publisher |
Copernicus Publications |
publishDate |
2016 |
url |
https://doi.org/10.5194/tc-10-597-2016 https://doaj.org/article/fdbf6c5720aa4af6adcda018b8099543 |
long_lat |
ENVELOPE(-49.917,-49.917,69.167,69.167) |
geographic |
Greenland Jakobshavn Isbræ |
geographic_facet |
Greenland Jakobshavn Isbræ |
genre |
glacier Greenland Jakobshavn Jakobshavn isbræ The Cryosphere |
genre_facet |
glacier Greenland Jakobshavn Jakobshavn isbræ The Cryosphere |
op_source |
The Cryosphere, Vol 10, Iss 2, Pp 597-611 (2016) |
op_relation |
http://www.the-cryosphere.net/10/597/2016/tc-10-597-2016.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 1994-0416 1994-0424 doi:10.5194/tc-10-597-2016 https://doaj.org/article/fdbf6c5720aa4af6adcda018b8099543 |
op_doi |
https://doi.org/10.5194/tc-10-597-2016 |
container_title |
The Cryosphere |
container_volume |
10 |
container_issue |
2 |
container_start_page |
597 |
op_container_end_page |
611 |
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1766009380224892928 |