Fast draining lakes on the Greenland Ice Sheet

Selmes, N.; Murray, Tavi; James, T. D.

doi:10.1029/2011gl047872

Cited by 159 publications

(292 citation statements)

References 18 publications

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“…These data reveal that lakes form seasonally in depressions in both the ablation and lower accumulation zones of the ice sheet [35], with their locations controlled by the underlying subglacial topography [36] or basal friction [37] thereby ensuring that they typically reform in the same location each year given sufficient surface meltwater.…”

Section: Supraglacial Meltwater Processesmentioning

confidence: 99%

“…The lakes can either drain rapidly by hydrofracture [9,41,42] or more slowly by overtopping their topographic lip and draining supraglacially downstream [43][44][45]; a 5-year study of 2000 Greenland-wide supraglacial lakes estimated that 13% of the lakes were 'fast-draining' (< 2 days) [35], while a 10-year catchment-based study of~200 lakes estimated that 28% of the lakes drained 'rapidly' (< 4 days) [38]. Rapid lake drainage results in large volumes of water entering the subglacial drainage system in a few hours with rates of 8700 and 3300 m 3 s −1 recorded [9,41].…”

Section: Supraglacial Meltwater Processesmentioning

confidence: 99%

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Recent Advances in Our Understanding of the Role of Meltwater in the Greenland Ice Sheet System

Nienow

Sole

Slater

et al. 2017

Curr Clim Change Rep

100

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Purpose of the Review This review discusses the role that meltwater plays within the Greenland ice sheet system. The ice sheet's hydrology is important because it affects mass balance through its impact on meltwater runoff processes and ice dynamics. The review considers recent advances in our understanding of the storage and routing of water through the supraglacial, englacial, and subglacial components of the system and their implications for the ice sheet. Recent Findings There have been dramatic increases in surface meltwater generation and runoff since the early 1990s, both due to increased air temperatures and decreasing surface albedo. Processes in the subglacial drainage system have similarities to valley glaciers and in a warming climate, the efficiency of meltwater routing to the ice sheet margin is likely to increase. The behaviour of the subglacial drainage system appears to limit the impact of increased surface melt on annual rates of ice motion, in sections of the ice sheet that terminate on land, while the large volumes of meltwater routed subglacially deliver significant volumes of sediment and nutrients to downstream ecosystems. Summary Considerable advances have been made recently in our understanding of Greenland ice sheet hydrology and its wider influences. Nevertheless, critical gaps persist both in our understanding of hydrology-dynamics coupling, notably at tidewater glaciers, and in runoff processes which ensure that projecting Greenland's future mass balance remains challenging.

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Section: Supraglacial Meltwater Processesmentioning

confidence: 99%

Section: Supraglacial Meltwater Processesmentioning

confidence: 99%

Recent Advances in Our Understanding of the Role of Meltwater in the Greenland Ice Sheet System

Nienow

Sole

Slater

et al. 2017

Curr Clim Change Rep

100

View full text Add to dashboard Cite

show abstract

“…At this point the lake will overtop and contribute to downstream runoff, which may flow into downstream crevasses if the lake has not already drained locally through modelled hydrofracture (Appendix C). Supraglacial lakes in Southwest Greenland are more numerous, have a larger total area, and have a larger frequency of fast drainage than anywhere else on the ice sheet (Selmes et al, 2011), making them an important feature of the Leverett glacier catchment.…”

Section: Meltwater Routing and Accumulation In Supraglacial Lakesmentioning

confidence: 99%

Modelling the transfer of supraglacial meltwater to the bed of Leverett Glacier, Southwest Greenland

et al. 2015

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Abstract. Meltwater delivered to the bed of the GreenlandIce Sheet is a driver of variable ice-motion through changes in effective pressure and enhanced basal lubrication. Ice surface velocities have been shown to respond rapidly both to meltwater production at the surface and to drainage of supraglacial lakes, suggesting efficient transfer of meltwater from the supraglacial to subglacial hydrological systems. Although considerable effort is currently being directed towards improved modelling of the controlling surface and basal processes, modelling the temporal and spatial evolution of the transfer of melt to the bed has received less attention. Here we present the results of spatially distributed modelling for prediction of moulins and lake drainages on the Leverett Glacier in Southwest Greenland. The model is run for the 2009 and 2010 ablation seasons, and for future increased melt scenarios. The temporal pattern of modelled lake drainages are qualitatively comparable with those documented from analyses of repeat satellite imagery. The modelled timings and locations of delivery of meltwater to the bed also match well with observed temporal and spatial patterns of ice surface speed-ups. This is particularly true for the lower catchment ( < 1000 m a.s.l.) where both the model and observations indicate that the development of moulins is the main mechanism for the transfer of surface meltwater to the bed. At higher elevations (e.g. 1250-1500 m a.s.l.) the development and drainage of supraglacial lakes becomes increasingly important. At these higher elevations, the delay between modelled melt generation and subsequent delivery of melt to the bed matches the observed delay between the peak air temperatures and subsequent velocity speed-ups, while the instantaneous transfer of melt to the bed in a control simulation does not. Although both moulins and lake drainages are predicted to increase in number for future warmer climate scenarios, the lake drainages play an increasingly important role in both expanding the area over which melt accesses the bed and in enabling a greater proportion of surface melt to reach the bed.

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“…Krawczynski et al (2009) calculated that supraglacial lakes 250 to 800 m across and 2 to 5 m deep contain sufficient water to drive a fracture to the base of kilometre-thick ice. Many lakes on the Greenland Ice Sheet attain this size or larger (Box and Ski, 2007;Echelmeyer et al, 1991;Georgiou et al, 2009), of which a small proportion (13 % between 2005-2009) drain in less than 2 days (Selmes et al, 2011). Surface lakes can drain rapidly into moulins via supraglacial rivers; however, many drain by the in situ propagation of hydraulically driven fractures (e.g.…”

Section: Introductionmentioning

confidence: 99%

Ice tectonic deformation during the rapid in situ drainage of a supraglacial lake on the Greenland Ice Sheet

et al. 2013

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Abstract. We present detailed records of lake discharge, ice motion and passive seismicity capturing the behaviour and processes preceding, during and following the rapid drainage of a ∼ 4 km 2 supraglacial lake through 1.1-km-thick ice on the western margin of the Greenland Ice Sheet. Peak discharge of 3300 m 3 s −1 coincident with maximal rates of vertical uplift indicates that surface water accessed the ice-bed interface causing widespread hydraulic separation and enhanced basal motion. The differential motion of four global positioning system (GPS) receivers located around the lake record the opening and closure of the fractures through which the lake drained. We hypothesise that the majority of discharge occurred through a ∼ 3-km-long fracture with a peak width averaged across its wetted length of ∼ 0.4 m. We argue that the fracture's kilometre-scale length allowed rapid discharge to be achieved by combining reasonable water velocities with sub-metre fracture widths. These observations add to the currently limited knowledge of in situ supraglacial lake drainage events, which rapidly deliver large volumes of water to the ice-bed interface.

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Fast draining lakes on the Greenland Ice Sheet

Cited by 159 publications

References 18 publications

Recent Advances in Our Understanding of the Role of Meltwater in the Greenland Ice Sheet System

Recent Advances in Our Understanding of the Role of Meltwater in the Greenland Ice Sheet System

Modelling the transfer of supraglacial meltwater to the bed of Leverett Glacier, Southwest Greenland

Ice tectonic deformation during the rapid in situ drainage of a supraglacial lake on the Greenland Ice Sheet

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