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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ftdoajarticles: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 2012-04-01T00:00:00Z https://doi.org/10.5194/tc-6-453-2012 https://doaj.org/article/6ed985f696654bd5b231e3f44353e169 EN eng Copernicus Publications http://www.the-cryosphere.net/6/453/2012/tc-6-453-2012.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-6-453-2012 1994-0416 1994-0424 https://doaj.org/article/6ed985f696654bd5b231e3f44353e169 The Cryosphere, Vol 6, Iss 2, Pp 453-466 (2012) Environmental sciences GE1-350 Geology QE1-996.5 article 2012 ftdoajarticles https://doi.org/10.5194/tc-6-453-2012 2022-12-31T11:04:53Z 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 2008–2010. 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 d −1 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 Directory of Open Access Journals: DOAJ Articles Svalbard Austfonna ENVELOPE(24.559,24.559,79.835,79.835) Kronebreen ENVELOPE(13.333,13.333,78.833,78.833) Duvebreen ENVELOPE(23.905,23.905,80.150,80.150) The Cryosphere 6 2 453 466 |
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 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 |
Environmental sciences GE1-350 Geology QE1-996.5 |
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 2008–2010. 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 d −1 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 https://doaj.org/article/6ed985f696654bd5b231e3f44353e169 |
long_lat |
ENVELOPE(24.559,24.559,79.835,79.835) ENVELOPE(13.333,13.333,78.833,78.833) ENVELOPE(23.905,23.905,80.150,80.150) |
geographic |
Svalbard Austfonna Kronebreen Duvebreen |
geographic_facet |
Svalbard Austfonna Kronebreen Duvebreen |
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 |
http://www.the-cryosphere.net/6/453/2012/tc-6-453-2012.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-6-453-2012 1994-0416 1994-0424 https://doaj.org/article/6ed985f696654bd5b231e3f44353e169 |
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 |
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1766364506057867264 |