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| Titel |
Thermal structure and drainage system of a small valley glacier (Tellbreen, Svalbard), investigated by ground penetrating radar |
| VerfasserIn |
K. Bælum, D. I. Benn |
| 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 ; 5, no. 1 ; Nr. 5, no. 1 (2011-03-04), S.139-149 |
| Datensatznummer |
250002277
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| Publikation (Nr.) |
 copernicus.org/tc-5-139-2011.pdf |
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| Zusammenfassung |
| Proglacial icings accumulate in front of many High Arctic glaciers during
the winter months, as water escapes from englacial or subglacial storage.
Such icings have been interpreted as evidence for warm-based subglacial
conditions, but several are now known to occur in front of cold-based
glaciers. In this study, we investigate the drainage system of Tellbreen, a
3.5 km long glacier in central Spitsbergen, where a large proglacial icing
develops each winter, to determine the location and geometry of storage
elements. Digital elevation models (DEMs) of the glacier surface and bed
were constructed using maps, differential GPS and ground penetrating radar
(GPR). Rates of surface lowering indicate that the glacier has a long-term
mass balance of −0.6 ± 0.2 m/year. Englacial and subglacial drainage
channels were mapped using GPR, showing that Tellbreen has a diverse
drainage system that is capable of storing, transporting and releasing water
year round. In the upper part of the glacier, drainage is mainly via
supraglacial channels. These transition downglacier into shallow englacial
"cut and closure" channels, formed by the incision and roof closure of
supraglacial channels. Below thin ice near the terminus, these channels
reach the bed and contain stored water throughout the winter months. Even
though no signs of temperate ice were detected and the bed is below
pressure-melting point, Tellbreen has a surface-fed, channelized subglacial
drainage system, which allows significant storage and delayed discharge. |
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