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Seasonal variations in Greenland Ice Sheet motion: Inland extent and behaviour at higher elevations

Citation

Bartholomew, ID and Nienow, P and Sole, A and Mair, D and Cowton, T and King, MA and Palmer, S, Seasonal variations in Greenland Ice Sheet motion: Inland extent and behaviour at higher elevations, Earth and Planetary Science Letters, 307, (3-4) pp. 271-278. ISSN 0012-821X (2011) [Refereed Article]

Copyright Statement

2011 Elsevier B.V. All rights reserved.

DOI: doi:10.1016/j.epsl.2011.04.014

Abstract

We present global positioning system observations that capture the full inland extent of ice motion variations in 2009 along a transect in the west Greenland Ice sheet margin. In situ measurements of air temperature and surface ablation, and satellite monitoring of ice surface albedo and supraglacial lake drainage are used to investigate hydrological controls on ice velocity changes. We find a strong positive correlation between rates of annual ablation and changes in annual ice motion along the transect, with sites nearest the ice sheet margin experiencing greater annual variations in ice motion (15-18%) than those above 1000. m elevation (3-8%). Patterns in the timing and rate of meltwater delivery to the ice-bed interface provide key controls on the magnitude of hydrologically-forced velocity variations at each site. In the lower ablation zone, the overall contribution of variations in ice motion to annual flow rates is limited by evolution in the structure of the subglacial drainage system. At sites in the upper ablation zone, a shorter period of summer melting and delayed establishment of a hydraulic connection between the ice sheet surface and its bed limit the timeframe for velocity variations to occur. Our data suggest that land-terminating sections of the Greenland Ice Sheet will experience increased dynamic mass loss in a warmer climate, as the behaviour that we observe in the lower ablation zone propagates further inland. Findings from this study provide a conceptual framework to understand the impact of hydrologically-forced velocity variations on the future mass balance of land-terminating sections of the Greenland Ice Sheet. © 2011 Elsevier B.V.

Item Details

Item Type:Refereed Article
Keywords:GPS; Greenland; Ice dynamics; Subglacial hydrology; Supraglacial lakes; Air temperature; Annual flow; Conceptual frameworks; Drainage systems; Greenland; Greenland Ice Sheet; Hydraulic connection; Hydrological controls; Ice dynamics; Ice motion; Ice
Research Division:Earth Sciences
Research Group:Physical Geography and Environmental Geoscience
Research Field:Physical Geography and Environmental Geoscience not elsewhere classified
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Earth Sciences
Author:King, MA (Professor Matt King)
ID Code:82154
Year Published:2011
Web of Science® Times Cited:66
Deposited By:Geography and Environmental Studies
Deposited On:2013-01-16
Last Modified:2017-10-24
Downloads:0

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