Seasonal speed-up of two outlet glaciers of Austfonna, Svalbard, inferred from continuous GPS measurements
A large part of the ice discharge from ice caps and ice sheets occurs through spatially limited flow units that may operate in a mode of steady flow or cyclic surge behaviour. Changes in the dynamics of distinct flow units play a key role in the mass balance of Austfonna, the largest ice cap on Sval...
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Language: | English |
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Copernicus Publications
2012
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Online Access: | https://doi.org/10.5194/tc-6-453-2012 http://www.the-cryosphere.net/6/453/2012/tc-6-453-2012.pdf https://doaj.org/article/6ed985f696654bd5b231e3f44353e169 |
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fttriple:oai:gotriple.eu:oai:doaj.org/article:6ed985f696654bd5b231e3f44353e169 2023-05-15T15:33:55+02:00 Seasonal speed-up of two outlet glaciers of Austfonna, Svalbard, inferred from continuous GPS measurements T. Dunse T. V. Schuler J. O. Hagen C. H. Reijmer 2012-04-01 https://doi.org/10.5194/tc-6-453-2012 http://www.the-cryosphere.net/6/453/2012/tc-6-453-2012.pdf https://doaj.org/article/6ed985f696654bd5b231e3f44353e169 en eng Copernicus Publications doi:10.5194/tc-6-453-2012 1994-0416 1994-0424 http://www.the-cryosphere.net/6/453/2012/tc-6-453-2012.pdf https://doaj.org/article/6ed985f696654bd5b231e3f44353e169 undefined The Cryosphere, Vol 6, Iss 2, Pp 453-466 (2012) geo envir Journal Article https://vocabularies.coar-repositories.org/resource_types/c_6501/ 2012 fttriple https://doi.org/10.5194/tc-6-453-2012 2023-01-22T19:11:22Z A large part of the ice discharge from ice caps and ice sheets occurs through spatially limited flow units that may operate in a mode of steady flow or cyclic surge behaviour. Changes in the dynamics of distinct flow units play a key role in the mass balance of Austfonna, the largest ice cap on Svalbard. The recent net mass loss of Austfonna was dominated by calving from marine terminating outlet glaciers. Previous ice-surface velocity maps of the ice cap were derived by satellite radar interferometry (InSAR) and rely on data acquired in the mid-1990s with limited information concerning the temporal variability. Here, we present continuous Global Positioning System (GPS) observations along the central flowlines of two fast flowing outlet glaciers over 2008ā2010. The data show prominent summer speed-ups with ice-surface velocities as high as 240% of the pre-summer mean. Acceleration follows the onset of the summer melt period, indicating enhanced basal motion due to input of surface meltwater into the subglacial drainage system. In 2008, multiple velocity peaks coincide with successive melt periods. In 2009, the major melt was of higher amplitude than in 2008. Flow velocities appear unaffected by subsequent melt periods, suggesting a transition towards a hydraulically more efficient drainage system. The observed annual mean velocities of Duvebreen and Basin-3 exceed those from the mid-1990s by factors two and four, respectively, implying increased ice discharge at the calving front. Measured summer velocities up to 2 m dā1 for Basin-3 are close to those of Kronebreen, often referred to as the fastest glacier on Svalbard. Article in Journal/Newspaper Austfonna glacier Ice cap Svalbard The Cryosphere Unknown Austfonna ENVELOPE(24.559,24.559,79.835,79.835) Duvebreen ENVELOPE(23.905,23.905,80.150,80.150) Kronebreen ENVELOPE(13.333,13.333,78.833,78.833) Svalbard The Cryosphere 6 2 453 466 |
institution |
Open Polar |
collection |
Unknown |
op_collection_id |
fttriple |
language |
English |
topic |
geo envir |
spellingShingle |
geo envir T. Dunse T. V. Schuler J. O. Hagen C. H. Reijmer Seasonal speed-up of two outlet glaciers of Austfonna, Svalbard, inferred from continuous GPS measurements |
topic_facet |
geo envir |
description |
A large part of the ice discharge from ice caps and ice sheets occurs through spatially limited flow units that may operate in a mode of steady flow or cyclic surge behaviour. Changes in the dynamics of distinct flow units play a key role in the mass balance of Austfonna, the largest ice cap on Svalbard. The recent net mass loss of Austfonna was dominated by calving from marine terminating outlet glaciers. Previous ice-surface velocity maps of the ice cap were derived by satellite radar interferometry (InSAR) and rely on data acquired in the mid-1990s with limited information concerning the temporal variability. Here, we present continuous Global Positioning System (GPS) observations along the central flowlines of two fast flowing outlet glaciers over 2008ā2010. The data show prominent summer speed-ups with ice-surface velocities as high as 240% of the pre-summer mean. Acceleration follows the onset of the summer melt period, indicating enhanced basal motion due to input of surface meltwater into the subglacial drainage system. In 2008, multiple velocity peaks coincide with successive melt periods. In 2009, the major melt was of higher amplitude than in 2008. Flow velocities appear unaffected by subsequent melt periods, suggesting a transition towards a hydraulically more efficient drainage system. The observed annual mean velocities of Duvebreen and Basin-3 exceed those from the mid-1990s by factors two and four, respectively, implying increased ice discharge at the calving front. Measured summer velocities up to 2 m dā1 for Basin-3 are close to those of Kronebreen, often referred to as the fastest glacier on Svalbard. |
format |
Article in Journal/Newspaper |
author |
T. Dunse T. V. Schuler J. O. Hagen C. H. Reijmer |
author_facet |
T. Dunse T. V. Schuler J. O. Hagen C. H. Reijmer |
author_sort |
T. Dunse |
title |
Seasonal speed-up of two outlet glaciers of Austfonna, Svalbard, inferred from continuous GPS measurements |
title_short |
Seasonal speed-up of two outlet glaciers of Austfonna, Svalbard, inferred from continuous GPS measurements |
title_full |
Seasonal speed-up of two outlet glaciers of Austfonna, Svalbard, inferred from continuous GPS measurements |
title_fullStr |
Seasonal speed-up of two outlet glaciers of Austfonna, Svalbard, inferred from continuous GPS measurements |
title_full_unstemmed |
Seasonal speed-up of two outlet glaciers of Austfonna, Svalbard, inferred from continuous GPS measurements |
title_sort |
seasonal speed-up of two outlet glaciers of austfonna, svalbard, inferred from continuous gps measurements |
publisher |
Copernicus Publications |
publishDate |
2012 |
url |
https://doi.org/10.5194/tc-6-453-2012 http://www.the-cryosphere.net/6/453/2012/tc-6-453-2012.pdf https://doaj.org/article/6ed985f696654bd5b231e3f44353e169 |
long_lat |
ENVELOPE(24.559,24.559,79.835,79.835) ENVELOPE(23.905,23.905,80.150,80.150) ENVELOPE(13.333,13.333,78.833,78.833) |
geographic |
Austfonna Duvebreen Kronebreen Svalbard |
geographic_facet |
Austfonna Duvebreen Kronebreen Svalbard |
genre |
Austfonna glacier Ice cap Svalbard The Cryosphere |
genre_facet |
Austfonna glacier Ice cap Svalbard The Cryosphere |
op_source |
The Cryosphere, Vol 6, Iss 2, Pp 453-466 (2012) |
op_relation |
doi:10.5194/tc-6-453-2012 1994-0416 1994-0424 http://www.the-cryosphere.net/6/453/2012/tc-6-453-2012.pdf https://doaj.org/article/6ed985f696654bd5b231e3f44353e169 |
op_rights |
undefined |
op_doi |
https://doi.org/10.5194/tc-6-453-2012 |
container_title |
The Cryosphere |
container_volume |
6 |
container_issue |
2 |
container_start_page |
453 |
op_container_end_page |
466 |
_version_ |
1766364506375585792 |