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Plastic bed beneath Hofsjökull Ice Cap, central Iceland, and the sensitivity of ice flow to surface meltwater flux

Plastic bed beneath Hofsjökull Ice Cap, central Iceland, and the sensitivity of ice flow to surface meltwater flux


Titill: Plastic bed beneath Hofsjökull Ice Cap, central Iceland, and the sensitivity of ice flow to surface meltwater flux
Höfundur: Minchew, Brent
Simons, Mark
Björnsson, Helgi
Pálsson, Finnur   orcid.org/0000-0002-0874-6443
Morlighem, Mathieu   orcid.org/0000-0001-5219-1310
Seroussi, Helene
Larour, Eric
Hensley, Scott
Útgáfa: 2016-02
Tungumál: Enska
Umfang: 147-158
Háskóli/Stofnun: Háskóli Íslands
University of Iceland
Svið: Verkfræði- og náttúruvísindasvið (HÍ)
School of Engineering and Natural Sciences (UI)
Deild: Jarðvísindastofnun (HÍ)
Institute of Earth Sciences (UI)
Birtist í: Journal of Glaciology;62(231)
ISSN: 0022-1430
1727-5652 (eISSN)
DOI: 10.1017/jog.2016.26
Efnisorð: Glaciology; Surface velocity; Basal mechanics; Basal plasticity; Basal hydrology; Jöklafræði; Jöklar; Basalt
URI: https://hdl.handle.net/20.500.11815/402

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Tilvitnun:

MINCHEW, B., SIMONS, M., BJÖRNSSON, H., PÁLSSON, F., MORLIGHEM, M., SEROUSSI, H., . . . HENSLEY, S. (2016). Plastic bed beneath Hofsjökull Ice Cap, central Iceland, and the sensitivity of ice flow to surface meltwater flux. Journal of Glaciology, 62(231), 147-158. doi:10.1017/jog.2016.26

Útdráttur:

The mechanical properties of glacier beds play a fundamental role in regulating the sensitivity of glaciers to environmental forcing across a wide range of timescales. Glaciers are commonly underlain by deformable till whose mechanical properties and influence on ice flow are not well understood but are critical for reliable projections of future glacier states. Using synoptic-scale observations of glacier motion in different seasons to constrain numerical ice flow models, we study the mechanics of the bed beneath Hofsjökull, a land-terminating ice cap in central Iceland. Our results indicate that the bed deforms plastically and weakens following incipient summertime surface melt. Combining the inferred basal shear traction fields with a Coulomb-plastic bed model, we estimate the spatially distributed effective basal water pressure and show that changes in basal water pressure and glacier accelerations are non-local and non-linear. These results motivate an idealized physical model relating mean basal water pressure and basal slip rate wherein the sensitivity of glacier flow to changes in basal water pressure is inversely related to the ice surface slope.

Leyfi:

This is an Open Access article, distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike licence (http://creativecommons.org/licenses/by-nc-sa/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the same Creative Commons licence is included and the original work is properly cited. The written permission of Cambridge University Press must be obtained for commercial re-use.

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