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Medientyp:
E-Artikel
Titel:
The Characteristics and Formation of a High-Arctic Proglacial Icing
Beteiligte:
Hodgkins, Richard;
Tranter, Martyn;
Dowdeswell, Julian A.
Erschienen:
Swedish Society for Anthropology and Geography, 2004
Erschienen in:Geografiska Annaler. Series A, Physical Geography
Sprache:
Englisch
ISSN:
0435-3676;
1468-0459
Entstehung:
Anmerkungen:
Beschreibung:
<p>Well-known from permafrost hydrology, icings (naled or Aufeis) are also frequently encountered at the margins of high-latitude glaciers. The morphology of a proglacial icing at Scott Turnerbreen in the Norwegian Arctic archipelago of Svalbard is described, and the process of formation is considered in detail. Ground thermal-regime modelling indicates an equilibrium permafrost depth of at least 200 m in the studied catchment, and it appears unlikely that groundwater contributes to icing formation. Meltwater flow through ice-marginal drainage channels is accompanied by estimated heat fluxes of up to about 190 W m<sup>-2</sup>, suggesting that stored meltwater may continue to percolate through thawed sub-channel sediments when surface runoff is absent during winter. A hydraulic conductivity of 6.9 × 10<sup>-3</sup>m s<sup>-1</sup>is implied, which is consistent with other studies of glacier drainage systems. The long residence time of winter-draining meltwater, and solute rejection by refreezing water, account for high observed concentrations of solute in interstitial water in the icing. It has often been asserted that the presence of a proglacial icing indicates that a glacier is polythermal. However, as Scott Turnerbeen is entirely non-temperate, the presence of an icing cannot always be treated as a reliable guide to the thermal regime of a glacier.</p>