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| Titel |
Surface speed and frontal ablation of Kronebreen and Kongsbreen, NW Svalbard, from SAR offset tracking |
| VerfasserIn |
T. Schellenberger, T. Dunse, A. Kääb, J. Köhler, C. H. Reijmer |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1994-0416
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| Digitales Dokument |
URL |
| Erschienen |
In: The Cryosphere ; 9, no. 6 ; Nr. 9, no. 6 (2015-12-15), S.2339-2355 |
| Datensatznummer |
250116884
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| Publikation (Nr.) |
 copernicus.org/tc-9-2339-2015.pdf |
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| Zusammenfassung |
| Kronebreen and Kongsbreen are among the fastest-flowing glaciers on
Svalbard and, therefore, important contributors to the total dynamic mass
loss from the archipelago. Here, we present a time series of area-wide
surface velocity fields from April 2012 to December 2013 based on offset
tracking on repeat high-resolution Radarsat-2 Ultrafine data. Surface speeds
reached up to 3.2 m d−1 near the calving front of Kronebreen in summer
2013 and 2.7 m d−1 at Kongsbreen in late autumn 2012. Additional
velocity fields from Radarsat-1, Radarsat-2 and TerraSAR-X data since
December 2007 together with continuous GPS measurements on Kronebreen since
September 2008 revealed complex patterns in seasonal and interannual speed
evolution. Part of the ice-flow variations seem closely linked to the amount
and timing of surface meltwater production and rainfall, both of which are
known to have a strong influence on the basal water pressure and hence basal
lubrication. In addition, terminus retreat and the associated reduction in
back stress appear to have influenced the speed close to the calving front,
especially at Kongsbreen in 2012 and 2013. Since 2007, Kongsbreen retreated
up to 1800 m, corresponding to a total area loss of 2.5 km2. In 2011
the retreat of Kronebreen of up to 850 m, responsible for a total area loss
of 2.8 km2, was triggered after a phase of stable terminus position
since ~ 1990. Retreat is an important component of the mass
balance of both glaciers, in which frontal ablation is the largest
component. Total frontal ablation between April 2012 and December 2013 was
estimated to 0.21–0.25 Gt a−1 for Kronebreen and 0.14–0.16 Gt a−1 for Kongsbreen. |
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