Upper bounds on subglacial channel development for interior regions of the Greenland Ice Sheet

Authors Organisations
Type Article
Original languageEnglish
Pages (from-to)1044-1052
Number of pages9
JournalJournal of Glaciology
Volume60
Issue number224
DOI
Publication statusPublished - 2014
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Abstract

We use a simple numerical model to test whether surface water influx to the bed of the interior Greenland ice sheet has the potential to cause significant subglacial channel growth similar to that observed near the ice-sheet margin and at alpine glaciers. We examine the effects on channel growth from (1) rapid supraglacial lake drainage events and (2) sustained water input into moulins. By
assuming that all drainage occurs through subglacial channels and by prescribing favorable pressure conditions at the domain inlet, the model can provide upper bounds on channel growth. Our results indicate that R-channels do not grow significantly within the limited period of high pressure associated
with lake drainage events. Subsequent channel growth only occurs with sustained pressures above overburden. Rapid closure of channels at low pressures suggests channels in the interior are unlikely to draw significant quantities of water from nearby distributed networks. These results indicate that other drainage mechanisms such as turbulent sheets or linked-cavity networks are likely to be of greater importance for interior subglacial drainage than the growth of channels.

Embargo until 01/07/2015

Keywords

  • arctic glaciology, glacier hydrology, glacier modelling, ice-sheetmodelling, subglacial processes