Modeling of subglacial hydrological development following rapid supraglacial lake drainage
The rapid drainage of supraglacial lakes injects substantial volumes of water to the bed of the Greenland ice sheet over short timescales. The effect of these water pulses on the development of basal hydrological systems is largely unknown. To address this, we develop a lake drainage model incorporating both (1) a subglacial radial flux element driven by elastic hydraulic jacking and (2) downstream drainage through a linked channelized and distributed system. Here we present the model and examine whether substantial, efficient subglacial channels can form during or following lake drainage events and their effect on the water pressure in the surrounding distributed system. We force the model with field data from a lake drainage site, 70 km from the terminus of Russell Glacier in West Greenland. The model outputs suggest that efficient subglacial channels do not readily form in the vicinity of the lake during rapid drainage and instead water is evacuated primarily by a transient turbulent sheet and the distributed system. Following lake drainage, channels grow but are not large enough to reduce the water pressure in the surrounding distributed system, unless preexisting channels are present throughout the domain. Our results have implications for the analysis of subglacial hydrological systems in regions where rapid lake drainage provides the primary mechanism for surface-to-bed connections.
Additional Information© 2015 American Geophysical Union. Received 8 SEP 2014; Accepted 8 MAY 2015; Accepted article online 14 MAY 2015; Published online 30 JUN 2015. For further information on the modeling methodology see the supporting information and/or contact C.F. Dow. This project was funded with NERC grant NE/G007195/1 and the Greenland Analogue Project. C.F.D. was funded by a NERC doctoral scholarship and a NASA Postdoctoral Program fellowship at the Goddard Space Flight Center, administered by Oak Ridge Associated Universities. The authors would like to thank Mauro Werder and Ian Hewitt for helpful discussions about the modeling approach. Three anonymous reviewers and the Associate Editor are thanked for their helpful suggestions that have improved this manuscript.
Published - jgrf204000.pdf
Supplemental Material - jgrf20400-sup-0001-supinfo.pdf