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

Awduron Sefydliadau
Math Erthygl
Iaith wreiddiolSaesneg
Tudalennau (o-i)1044-1052
Nifer y tudalennau9
CyfnodolynJournal of Glaciology
Rhif y cyfnodolyn224
Dangosyddion eitem ddigidol (DOIs)
StatwsCyhoeddwyd - 2014
Cysylltiad parhaol
Arddangos ystadegau lawrlwytho
Gweld graff cysylltiadau
Fformatau enwi


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