Firn profile changes in response to extreme 21st-century melting at Devon Ice Cap, Nunavut, Canada

Bezeau, Peter; Sharp, Martin; Burgess, David; Gascon, Gabrielle

doi:10.3189/2013jog12j208

Cited by 36 publications

(73 citation statements)

References 31 publications

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“…However, similar changes in firn structure are observed in the Canadian Arctic 19,20,21 . A study of Greenland's percolation area 250 km north of our study site also indicates ice formation in the near surface 22 .…”

mentioning

confidence: 51%

Greenland meltwater storage in firn limited by near-surface ice formation

et al. 2016

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mentioning

confidence: 51%

Greenland meltwater storage in firn limited by near-surface ice formation

et al. 2016

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“…Ice layer‐derived melt records from cores recovered from ice caps in the QEI show that melt rates in the last 25 years have been the highest in the last 2000 years [ Fisher et al ., ]. Latent heat released during the refreezing of meltwater percolating into firn has contributed substantially to raising firn temperatures by as much as 10°C on Penny Ice Cap (Baffin Island) since the mid 1990s [ Zdanowicz et al ., ] and by as much as 3.8°C on Devon Ice Cap since 2004 [ Bezeau et al ., ]. However, very little is known about exactly how freezing of percolating meltwater will fill the available pore volume in firn as climate warms, or how the pattern of pore filling will influence the relationship between surface melt and runoff.…”

Section: Introductionmentioning

confidence: 99%

“…[]. This scenario is consistent with recent observations from the accumulation area of the Devon Ice Cap, where comparisons of density profiles of firn cores drilled in 2004 and 2012 showed formation of thick ice layers close to the ice cap surface and increases of 13–80% in the densification rate of the top 2.5 m of the firn column over the intervening time period [ Bezeau et al ., ]. These changes accompanied the increase in surface melt and refreezing since 2005 and resulted in the ~150 m above sea level (asl) migration of the superimposed ice zone to higher elevation between 2004 and 2012.…”

Section: Introductionmentioning

confidence: 99%

Changes in accumulation-area firn stratigraphy and meltwater flow during a period of climate warming: Devon Ice Cap, Nunavut, Canada

Gascon

Sharp

Burgess

et al. 2013

J. Geophys. Res. Earth Surf.

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[1] To document climate-driven changes in firn stratigraphy and their implications for meltwater flow patterns within firn on the Devon Ice Cap, Nunavut, during the 21st century summer warming, 500 MHz ground-penetrating radar (GPR) surveys were conducted along a 40 km transect in each spring from 2007 to 2012. These linear GPR surveys were supplemented by four 190 m by 100 m GPR grid surveys and 36 firn cores. Increased meltwater percolation and infiltration ice formation associated with high surface melt rates since 2005 modified the firn stratigraphy substantially over a horizontal distance of nearly 30 km. The most dramatic change involved the growth of a thick ice layer within the firn body. This layer grew primarily by upward accretion over an initial widespread ice layer formed during summer 2005. It thickened by between 0.5 and 4.5 m over the study period and filled much of the pore volume in the upper part of the firn, reducing vertical percolation of meltwater into deeper sections of the firn and thus the water storage potential of much of the firn reservoir. Heterogeneous percolation of surface meltwater promoted by rolling topography played an important role in meltwater infiltration and drainage, encouraging lateral flow at the tops of small hills and ponding and refreezing of meltwater beneath surface depressions.

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“…The geodetically-derived, steady-state mass balance rate at the summit for The surface elevation can also lower due to melting and refreezing accelerating firnification (Bezeau et al, 2013). As shown per year (2σ) (Thompson et al, 2013).…”

Section: Accumulation Zonementioning

confidence: 99%