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| Titel |
A numerical model for meltwater channel evolution in glaciers |
| VerfasserIn |
A. H. Jarosch, M. T. Gudmundsson |
| 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 ; 6, no. 2 ; Nr. 6, no. 2 (2012-04-16), S.493-503 |
| Datensatznummer |
250003494
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| Publikation (Nr.) |
 copernicus.org/tc-6-493-2012.pdf |
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| Zusammenfassung |
| Meltwater channels form an integral part of the hydrological system of
a glacier. Better understanding of how meltwater channels develop and
evolve is required to fully comprehend supraglacial and englacial
meltwater drainage. Incision of supraglacial stream channels and
subsequent roof closure by ice deformation has been proposed in recent
literature as a possible englacial conduit formation process. Field
evidence for supraglacial stream incision has been found in Svalbard and
Nepal. In Iceland, where volcanic activity provides meltwater with
temperatures above 0 °C, rapid enlargement of supraglacial
channels has been observed. Supraglacial channels provide meltwater
through englacial passages to the subglacial hydrological systems of big
ice sheets, which in turn affects ice sheet motion and their contribution
to eustatic sea level change. By coupling, for the first time, a numerical
ice dynamic model to a hydraulic model which includes heat transfer, we
investigate the evolution of meltwater channels and their incision
behaviour. We present results for different, constant meltwater fluxes,
different channel slopes, different meltwater temperatures, different
melt rate distributions in the channel as well as temporal variations in
meltwater flux. The key parameters governing incision rate and depth are
channel slope, meltwater temperature loss to the ice and meltwater flux.
Channel width and geometry are controlled by melt rate distribution along
the channel wall. Calculated Nusselt numbers suggest that turbulent mixing
is the main heat transfer mechanism in the meltwater channels studied. |
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