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| Titel |
Near-surface permeability in a supraglacial drainage basin on the Llewellyn Glacier, Juneau Icefield, British Columbia |
| VerfasserIn |
L. Karlstrom, A. Zok, M. Manga |
| 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 (2014-03-27), S.537-546 |
| Datensatznummer |
250116084
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| Publikation (Nr.) |
 copernicus.org/tc-8-537-2014.pdf |
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| Zusammenfassung |
| Supraglacial channel networks link time varying melt production and
meltwater routing on temperate glaciers. Such channel networks often include
components of both surface transport in streams and subsurface porous flow
through near-surface ice, firn or snowpack. Although subsurface transport if
present will likely control network transport efficacy, it is the most poorly
characterized component of the system. We present measurements of
supraglacial channel spacing and network properties on the Juneau Icefield,
subsurface water table height, and time variation of hydraulic
characteristics including diurnal variability in water temperature. We
combine these data with modeling of porous flow in weathered ice to infer
near-surface permeability. Estimates are based on an observed phase lag
between diurnal water temperature variations and discharge, and independently
on measurement of water table surface elevation away from a stream. Both
methods predict ice permeability on a 1–10 m scale in the range of
10−10–10−11 m2. These estimates are considerably smaller than
common parameterizations of surface water flow on bare ice in the literature,
as well as smaller than most estimates of snowpack permeability. For
supraglacial environments in which porosity/permeability creation in the
subsurface is balanced by porous flow of meltwater, our methods provide an
estimate of microscale hydraulic properties from observations of supraglacial
channel spacing. |
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