A decadal investigation of supraglacial lakes in West Greenland using a fully automatic detection and tracking algorithm

Liang, Yuli; Colgan, William; Lv, Qin; Steffen, Konrad; Abdalati, W.; Stroeve, Julienne; Gallaher, D. W.; Bayou, N.

doi:10.1016/j.rse.2012.03.020

Cited by 106 publications

(163 citation statements)

References 27 publications

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“…Although no evidence of extensive lateral hydrological pathways was found at any of our field sites, it is likely that if melt continues to exceed total accumulation, water will soon be transported to lower elevations by supraglacial flow, especially during years experiencing extreme melt. Recent studies show that lakes are increasingly found at higher elevations (Banwell et al, 2012;Liang et al, 2012;Howat et al, 2013), and it is unclear how the percolation zone will evolve if more meltwater ponds are being formed over firn. Furthermore, according to RACMO2.3, if current warming trends continue, the percolation zone will potentially extend to most areas above the equilibrium line.…”

Section: Discussionmentioning

confidence: 99%

Changes in the firn structure of the western Greenland Ice Sheet caused by recent warming

et al. 2015

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Abstract. Atmospheric warming over the Greenland Ice Sheet during the last 2 decades has increased the amount of surface meltwater production, resulting in the migration of melt and percolation regimes to higher altitudes and an increase in the amount of ice content from refrozen meltwater found in the firn above the superimposed ice zone. Here we present field and airborne radar observations of buried ice layers within the near-surface (0-20 m) firn in western Greenland, obtained from campaigns between 1998 and 2014. We find a sharp increase in firn-ice content in the form of thick widespread layers in the percolation zone, which decreases the capacity of the firn to store meltwater. The estimated total annual ice content retained in the near-surface firn in areas with positive surface mass balance west of the ice divide in Greenland reached a maximum of 74 ± 25 Gt in 2012, compared to the 1958-1999 average of 13 ± 2 Gt, while the percolation zone area more than doubled between 2003 and 2012. Increased melt and column densification resulted in surface lowering averaging −0.80 ± 0.39 m yr −1 between 1800 and 2800 m in the accumulation zone of western Greenland. Since 2007, modeled annual melt and refreezing rates in the percolation zone at elevations below 2100 m surpass the annual snowfall from the previous year, implying that mass gain in the region is retained after melt in the form of refrozen meltwater. If current melt trends over high elevation regions continue, subsequent changes in firn structure will have implications for the hydrology of the ice sheet and related abrupt seasonal densification could become increasingly significant for altimetry-derived ice sheet mass balance estimates.

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Section: Discussionmentioning

confidence: 99%

Changes in the firn structure of the western Greenland Ice Sheet caused by recent warming

et al. 2015

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“…Therefore, if lake formation is dependent only on meltwater volume and firn layer thickness, we would expect lakes to form at correspondingly higher elevations. Previous work has shown that the distribution of lake surface area does shift to higher elevations in warmer years (Liang et al, 2012). However, a lack of surface undulations on thicker ice may prevent lakes from forming further inland.…”

Section: Expansion Of Meltwater Lakes On the Greenland Ice Sheetmentioning

confidence: 96%

<i>Brief Communication</i> "Expansion of meltwater lakes on the Greenland Ice Sheet"

et al. 2013

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Abstract. Forty years of satellite imagery reveal that meltwater lakes on the margin of the Greenland Ice Sheet have expanded substantially inland to higher elevations with warming. These lakes are important because they provide a mechanism for bringing water to the ice bed, causing sliding. Inland expansion of lakes could accelerate ice flow by bringing water to previously frozen bed, potentially increasing future rates of mass loss. Increasing lake elevations closely follow the rise of the mass balance equilibrium line over much of the ice sheet, suggesting no physical limit on lake expansion. Data are not yet available to detect a corresponding change in ice flow, and the potential effects of lake expansion on ice sheet dynamics are not included in ice sheet models.

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“…The integrated effect of multiple lake tapping events, and continued water flow into the hydraulic pathways they create, has the capacity to impact the annual ice flux in future years, especially as, in a warming climate, lakes are expected to form and drain earlier in the season (Liang et al, 2012) and at higher elevations (Howat et al, 2012). It is, however, uncertain whether this increase in water delivery will enhance the annual ice flux through a net increase in basal lubrication (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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A decadal investigation of supraglacial lakes in West Greenland using a fully automatic detection and tracking algorithm

Cited by 106 publications

References 27 publications

Changes in the firn structure of the western Greenland Ice Sheet caused by recent warming

Changes in the firn structure of the western Greenland Ice Sheet caused by recent warming

<i>Brief Communication</i> "Expansion of meltwater lakes on the Greenland Ice Sheet"

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

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A decadal investigation of supraglacial lakes in West Greenland using a fully automatic detection and tracking algorithm

Cited by 106 publications

References 27 publications

Changes in the firn structure of the western Greenland Ice Sheet caused by recent warming

Changes in the firn structure of the western Greenland Ice Sheet caused by recent warming

&lt;i&gt;Brief Communication&lt;/i&gt; &quot;Expansion of meltwater lakes on the Greenland Ice Sheet&quot;

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

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Product

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<i>Brief Communication</i> "Expansion of meltwater lakes on the Greenland Ice Sheet"