Mass changes of the Greenland and Antarctic ice sheets and shelves and contributions to sea-level rise: 1992–2002

Zwally, H. Jay; Giovinetto, Mario B.; Li, Jun; Cornejo, H.; Beckley, Matthew; Brenner, Anita C.; Saba, J. L. R.; Yi, Donghui

doi:10.3189/172756505781829007

Cited by 466 publications

(575 citation statements)

References 59 publications

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“…It is known that the arctic region is warming and that the margins of the Greenland Ice Sheet are experiencing substantial thinning (Hassol, 2004;Steffen et al, 2004;Zwally et al, 2005;Pritchard et al, 2009). Increasing fresh water input from the Greenland Ice Sheet (GrIS) to the oceans has created a growing concern about the effects it could have on climate and sea level rise.…”

Section: Introductionmentioning

confidence: 99%

“…Although changes in the volume of an ice sheet may be estimated by observing variations in its surface elevation (e.g. Wingham et al, 1998;Shepherd et al, 2001 andZwally et al, 2005) and from gravity measurements (e.g. Velicogna, 2009), these methods do not distinguish ice dynamics and accumulation fluctuations which may introduce errors in mass balance estimates.…”

Section: Introductionmentioning

confidence: 99%

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Spatially extensive estimates of annual accumulation in the dry snow zone of the Greenland Ice Sheet determined from radar altimetry

et al. 2010

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Abstract. We present estimates of accumulation rate along a 200 km transect ranging in elevation from 2750 to 3150 m in the dry snow zone on the western slope of the Greenland Ice Sheet. An airborne radar altimeter is used to estimate the thickness of annual internal layers and, in conjunction with ground based snow/firn density profiles, annual accumulation rates between 1998 and 2003 are derived. A clear gradient in the thickness of each layer observed by the radar altimeter and in the associated estimates of annual accumulation is seen along the transect, with a 33.6%± 16% mean decrease in accumulation from west to east. The observed inter-annual variability is high, with the annual mean accumulation rate estimated at 0.359 m.w.e. yr −1 (s.d. ± 0.049 m.w.e. yr −1 ). Mean accumulation rates modelled using meteorological models overestimate our results by 16% on average, but by 32% and 42% in the years 2001 and 2002. The methodology presented here demonstrates the potential to obtain accurate and spatially extensive accumulation rates from radar altimeters in regions of ice sheets where field observations are sparse, and accumulation rates greater than several tens of cm.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Spatially extensive estimates of annual accumulation in the dry snow zone of the Greenland Ice Sheet determined from radar altimetry

et al. 2010

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“…Strong interactions exist between surface meltwater production and the sliding behaviour of the ice sheet in west Greenland (Zwally et al, 2005;Van de Wal et al, 2008;Joughin et al, 2008;Shepherd et al, 2009), a process that is linked to the formation and decay of subglacial meltwater channels (Schoof, 2010). The increase in runoff since 1990, following atmospheric warming (Box and Cohen, 2006;Hanna et al, 2008), explains more than half of the recent mass loss of the GrIS ( Van den Broeke, 2009a).…”

Section: Introductionmentioning

confidence: 99%

The seasonal cycle and interannual variability of surface energy balance and melt in the ablation zone of the west Greenland ice sheet

2011

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Abstract. We present the seasonal cycle and interannual variability of the surface energy balance (SEB) in the ablation zone of the west Greenland ice sheet, using seven years (S9) at distances of 6, 38 and 88 km from the ice sheet margin. The hourly AWS data are fed into a model that calculates all SEB components and melt rate; the model allows for shortwave radiation penetration in ice and time-varying surface momentum roughness. Snow depth is prescribed from albedo and sonic height ranger observations. Modelled and observed surface temperatures for non-melting conditions agree very well, with RMSE's of 0.97-1.26 K. Modelled and observed ice melt rates at the two lowest sites also show very good agreement, both for total cumulative and 10-day cumulated amounts. Melt frequencies and melt rates at the AWS sites are discussed. Although absorbed shortwave radiation is the most important energy source for melt at all three sites, interannual melt variability at the lowest site is driven mainly by variability in the turbulent flux of sensible heat. This is explained by the quasi-constant summer albedo in the lower ablation zone, limiting the influence of the melt-albedo feedback, and the proximity of the snow free tundra, which heats up considerably in summer.Correspondence to: M. R. van den Broeke (m.r.vandenbroeke@uu.nl)

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“…Research now recognises that these processes act to drive the expansion, break-up and collapse of major ice streams and ice masses (MacAyeal, 1993;Clark, 1994;Tulaczyk et al, 2000;Bell et al, 2007;Stokes et al, 2007;Burke et al, 2012) thus linking subglacial drainage to collapsing ice masses, sea-level change and abrupt climate change (Goezler et al, 2011;King et al, 2012;Hanna et al, 2013;Fürst et al, 2014 and references therein). Indeed, subglacial meltwater systems underpin major global issues surrounding the stability of the modern Antarctic and Greenland ice sheets, their sensitivity too and influence on current and future changes in sea-level and climate (Alley et al, 2005;Zwally et al, 2005;Shepherd & Wingham, 2007;Pfeffer et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Sedimentary and structural evolution of a relict subglacial to subaerial drainage system and its hydrogeological implications: an example from Anglesey, north Wales, UK

Lee

Wakefield

Phillips

et al. 2015

Quaternary Science Reviews

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Subglacial drainage systems exert a major control on basal-sliding rates and glacier dynamics. However, comparatively few studies have examined the sedimentary record of subglacial drainage. This is due to the paucity of modern analogues, the limited recognition and preservation of upper flow regime deposits within the geological record, and the difficulty of distinguishing subglacial meltwater deposits from other meltwater sediments (e.g. glacier outburst flood deposits). Within this study, the sedimentological and structural evolution of a subglacial to subaerial (ice-marginal / proglacial) drainage system is examined. Particular emphasis is placed upon the genetic development and preservation of upper flow regime bedforms and specifically recognising them within a subglacial meltwater context. Facies attributed to subglacial meltwater activity record sedimentation within a confined, but progressively enlargening, subglacial channel system produced under dune to upper flow regime conditions. Bedforms include rare large-scale sinusoidal bedding with syn-depositional deformation produced by current-induced traction and shearing within the channel margins. Subglacial sedimentation culminated with the abrupt change to a more ephemeral drainage regime indicating channel-abandonment or a seasonal drainage regime. Retreat of the ice margin, led to the establishment of subaerial drainage with phases of sheet-flow punctuated by channel incision and anastomosing channel development under diurnal, ablation-related, seasonal discharge. The presence of extensive hydrofracture networks demonstrate that proglacial groundwater-levels fluctuated markedly and this may have influenced later overriding of the site by an ice stream.

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Mass changes of the Greenland and Antarctic ice sheets and shelves and contributions to sea-level rise: 1992–2002

Cited by 466 publications

References 59 publications

Spatially extensive estimates of annual accumulation in the dry snow zone of the Greenland Ice Sheet determined from radar altimetry

Spatially extensive estimates of annual accumulation in the dry snow zone of the Greenland Ice Sheet determined from radar altimetry

The seasonal cycle and interannual variability of surface energy balance and melt in the ablation zone of the west Greenland ice sheet

Sedimentary and structural evolution of a relict subglacial to subaerial drainage system and its hydrogeological implications: an example from Anglesey, north Wales, UK

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