Journal cover Journal topic
The Cryosphere An interactive open-access journal of the European Geosciences Union
The Cryosphere, 9, 2339-2355, 2015
http://www.the-cryosphere.net/9/2339/2015/
doi:10.5194/tc-9-2339-2015
© Author(s) 2015. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
15 Dec 2015
Surface speed and frontal ablation of Kronebreen and Kongsbreen, NW Svalbard, from SAR offset tracking
T. Schellenberger1, T. Dunse1, A. Kääb1, J. Kohler2, and C. H. Reijmer3 1Department of Geosciences, University of Oslo, P.O. Box 1047, Blindern, 0316 Oslo, Norway
2Norwegian Polar Institute, Fram Centre, Tromsø, Norway
3Institute for Marine and Atmospheric Research Utrecht, Utrecht University, Princetonplein 5, 3584 CC Utrecht, the Netherlands
Abstract. 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.

Citation: Schellenberger, T., Dunse, T., Kääb, A., Kohler, J., and Reijmer, C. H.: Surface speed and frontal ablation of Kronebreen and Kongsbreen, NW Svalbard, from SAR offset tracking, The Cryosphere, 9, 2339-2355, doi:10.5194/tc-9-2339-2015, 2015.
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Short summary
Kronebreen and Kongsbreen are among the fastest flowing glaciers on Svalbard, and surface speeds reached up to 3.2m d-1 at Kronebreen in summer 2013 and 2.7m d-1 at Kongsbreen in late autumn 2012 as retrieved from SAR satellite data. Both glaciers retreated significantly during the observation period, Kongsbreen up to 1800m or 2.5km2 and Kronebreen up to 850m or 2.8km2. Both glaciers are important contributors to the total dynamic mass loss from the Svalbard archipelago.
Kronebreen and Kongsbreen are among the fastest flowing glaciers on Svalbard, and surface speeds...
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