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 marineterminating 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 mo...

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Published in:The Cryosphere
Main Authors: Muresan, Ioana S., Khan, Shfaqat A., Aschwanden, Andy, Khroulev, Constantine, Van Dam, Tonie, Bamber, Jonathan, Broeke, Michiel R Van Den, Wouters, Bert, Kuipers Munneke, Peter, Kjær, Kurt H.
Format: Article in Journal/Newspaper
Language:English
Published: 2016
Subjects:
Online Access:https://hdl.handle.net/1983/66f5754a-8ce2-4cc7-bd19-66bae7ca0187
https://research-information.bris.ac.uk/en/publications/66f5754a-8ce2-4cc7-bd19-66bae7ca0187
https://doi.org/10.5194/tc-10-597-2016
https://research-information.bris.ac.uk/ws/files/70861015/tc_10_597_2016.pdf
http://www.scopus.com/inward/record.url?scp=84961279263&partnerID=8YFLogxK
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spelling ftubristolcris:oai:research-information.bris.ac.uk:publications/66f5754a-8ce2-4cc7-bd19-66bae7ca0187 2024-01-28T10:05:55+01:00 Modelled glacier dynamics over the last quarter of a century at Jakobshavn Isbræ Muresan, Ioana S. Khan, Shfaqat A. Aschwanden, Andy Khroulev, Constantine Van Dam, Tonie Bamber, Jonathan Broeke, Michiel R Van Den Wouters, Bert Kuipers Munneke, Peter Kjær, Kurt H. 2016-03-15 application/pdf https://hdl.handle.net/1983/66f5754a-8ce2-4cc7-bd19-66bae7ca0187 https://research-information.bris.ac.uk/en/publications/66f5754a-8ce2-4cc7-bd19-66bae7ca0187 https://doi.org/10.5194/tc-10-597-2016 https://research-information.bris.ac.uk/ws/files/70861015/tc_10_597_2016.pdf http://www.scopus.com/inward/record.url?scp=84961279263&partnerID=8YFLogxK eng eng info:eu-repo/semantics/openAccess Muresan , I S , Khan , S A , Aschwanden , A , Khroulev , C , Van Dam , T , Bamber , J , Broeke , M R V D , Wouters , B , Kuipers Munneke , P & Kjær , K H 2016 , ' Modelled glacier dynamics over the last quarter of a century at Jakobshavn Isbræ ' , Cryosphere , vol. 10 , no. 2 , pp. 597-611 . https://doi.org/10.5194/tc-10-597-2016 article 2016 ftubristolcris https://doi.org/10.5194/tc-10-597-2016 2024-01-04T23:48:37Z Observations over the past 2 decades show substantial ice loss associated with the speed-up of marineterminating 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 breakup 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 University of Bristol: Bristol Research Greenland Jakobshavn Isbræ ENVELOPE(-49.917,-49.917,69.167,69.167) The Cryosphere 10 2 597 611
institution Open Polar
collection University of Bristol: Bristol Research
op_collection_id ftubristolcris
language English
description Observations over the past 2 decades show substantial ice loss associated with the speed-up of marineterminating 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 breakup 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 Muresan, Ioana S.
Khan, Shfaqat A.
Aschwanden, Andy
Khroulev, Constantine
Van Dam, Tonie
Bamber, Jonathan
Broeke, Michiel R Van Den
Wouters, Bert
Kuipers Munneke, Peter
Kjær, Kurt H.
spellingShingle Muresan, Ioana S.
Khan, Shfaqat A.
Aschwanden, Andy
Khroulev, Constantine
Van Dam, Tonie
Bamber, Jonathan
Broeke, Michiel R Van Den
Wouters, Bert
Kuipers Munneke, Peter
Kjær, Kurt H.
Modelled glacier dynamics over the last quarter of a century at Jakobshavn Isbræ
author_facet Muresan, Ioana S.
Khan, Shfaqat A.
Aschwanden, Andy
Khroulev, Constantine
Van Dam, Tonie
Bamber, Jonathan
Broeke, Michiel R Van Den
Wouters, Bert
Kuipers Munneke, Peter
Kjær, Kurt H.
author_sort Muresan, Ioana S.
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
publishDate 2016
url https://hdl.handle.net/1983/66f5754a-8ce2-4cc7-bd19-66bae7ca0187
https://research-information.bris.ac.uk/en/publications/66f5754a-8ce2-4cc7-bd19-66bae7ca0187
https://doi.org/10.5194/tc-10-597-2016
https://research-information.bris.ac.uk/ws/files/70861015/tc_10_597_2016.pdf
http://www.scopus.com/inward/record.url?scp=84961279263&partnerID=8YFLogxK
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
genre_facet glacier
Greenland
Jakobshavn
Jakobshavn isbræ
op_source Muresan , I S , Khan , S A , Aschwanden , A , Khroulev , C , Van Dam , T , Bamber , J , Broeke , M R V D , Wouters , B , Kuipers Munneke , P & Kjær , K H 2016 , ' Modelled glacier dynamics over the last quarter of a century at Jakobshavn Isbræ ' , Cryosphere , vol. 10 , no. 2 , pp. 597-611 . https://doi.org/10.5194/tc-10-597-2016
op_rights info:eu-repo/semantics/openAccess
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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