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| Titel |
Surge dynamics in the Nathorstbreen glacier system, Svalbard |
| VerfasserIn |
M. Sund, T. R. Lauknes, T. Eiken |
| 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 ; 8, no. 2 ; Nr. 8, no. 2 (2014-04-11), S.623-638 |
| Datensatznummer |
250116090
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| Publikation (Nr.) |
 copernicus.org/tc-8-623-2014.pdf |
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| Zusammenfassung |
| Nathorstbreen glacier system (NGS) recently experienced the largest surge in
Svalbard since 1936, and this was examined using spatial and temporal
observations from DEM differencing, time series of surface velocities from
satellite synthetic aperture radar (SAR) and other sources. The upper basins
with maximum accumulation during quiescence corresponded to regions of
initial lowering. Initial speed-up exceeded quiescent velocities by a factor
of several tens. This suggests that polythermal glacier surges are initiated
in the temperate area before mass is displaced downglacier. Subsequent
downglacier mass displacement coincided with areas where glacier velocity
increased by a factor of 100–200 times (stage 2). After more than 5 years,
the joint NGS terminus advanced abruptly into the fjord during winter,
increasing velocities even more. The advance was followed by up-glacier
propagation of crevasses, indicating the middle and subsequently the upper
part of the glaciers reacting to the mass displacement. NGS advanced
~15 km, while another ~3 km length was lost
due to calving. Surface lowering of ~50 m was observed in
some up-glacier areas, and in 5 years the total glacier area increased by 20%.
Maximum measured flow rates were at least 25 m d−1, 2500 times
quiescent velocity, while average velocities were about 10 m d−1. The
surges of Zawadzkibreen cycle with ca. 70-year periods. |
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