Effect of near‐terminus subglacial hydrology on tidewater glacier submarine melt rates

Slater, Donald; Nienow, Peter; Cowton, Tom; Goldberg, David M.; Sole, Andrew

doi:10.1002/2014gl062494

Cited by 125 publications

(255 citation statements)

References 37 publications

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“…Existing models of submarine melt and near-terminus water circulation assume vertical, planar tidewater glacier termini [Jenkins, 2011;Xu et al, 2012Xu et al, , 2013Sciascia et al, 2013;Carroll et al, 2015;Slater et al, 2015]. Our observations emphasize the need to account for the full 3-D context at the ice/ocean interface when considering buoyant outflow plume dynamics.…”

Section: Discussionmentioning

confidence: 76%

“…While it is hypothesized that the discharge of subglacial water into the proglacial fjord at discrete points influences submarine melt rates [Jenkins, 2011;Slater et al, 2015;Straneo and Cenedese, 2015], few observations of the size, number, and locations of channels exist. The extent to which more abundant, secondary channel outlets influence melt at the terminus remains unexplored despite the large rates of submarine melt they can potentially drive [Slater et al, 2015]. Second, the morphology of the submarine terminus face is largely unknown (with the exception of Rignot et al [2015]).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Distributed subglacial discharge drives significant submarine melt at a Greenland tidewater glacier

Fried

Catania

Bartholomaus

et al. 2015

Geophysical Research Letters

169

206

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Submarine melt can account for substantial mass loss at tidewater glacier termini. However, the processes controlling submarine melt are poorly understood due to limited observations of submarine termini. Here at a tidewater glacier in central West Greenland, we identify subglacial discharge outlets and infer submarine melt across the terminus using direct observations of the submarine terminus face. We find extensive melting associated with small discharge outlets. While the majority of discharge is routed to a single, large channel, outlets not fed by large tributaries drive submarine melt rates in excess of 3.0 m d−1 and account for 85% of total estimated melt across the terminus. Nearly the entire terminus is undercut, which may intersect surface crevasses and promote calving. Severe undercutting constricts buoyant outflow plumes and may amplify melt. The observed morphology and melt distribution motivate more realistic treatments of terminus shape and subglacial discharge in submarine melt models.

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Section: Discussionmentioning

confidence: 76%

Section: Introductionmentioning

confidence: 99%

Distributed subglacial discharge drives significant submarine melt at a Greenland tidewater glacier

Fried

Catania

Bartholomaus

et al. 2015

Geophysical Research Letters

169

206

View full text Add to dashboard Cite

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“…The near-terminus subglacial hydrology is also known to modulate the strength of fjord circulation [119] and submarine melting of the calving front [120]. The subglacial hydrology of tidewater glaciers is therefore likely to play a key part in Greenland's dynamic response to future climate warming, yet it remains very poorly understood.…”

Section: The Influence Of Hydrology On Marine Terminating ('Tidewatermentioning

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

Self Cite

104

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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“…Modified from Cowton et al [20] These findings indicate that melt-undercutting is sensitive to ocean temperature, glacier runoff, and the morphology of the subglacial hydrological system. Runoff input from a single channel produces a small zone of highly concentrated melting, whereas distributing runoff more evenly across the width of the glacier decreases the maximum local melt rates but can increase the total submarine melting of the calving front by a factor of 5 [51,52]. This is likely a significant consideration with respect to the effect of melt-undercutting on calving: small melt rates distributed across the full terminus width may have a different impact on terminus stability than one or a few zones of focused melting (see below).…”

Section: Processes Of Frontal Ablationmentioning

confidence: 99%

Glacier Calving in Greenland

Benn

Cowton

Todd

et al. 2017

Curr Clim Change Rep

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In combination, the breakaway of icebergs (calving) and submarine melting at marine-terminating glaciers account for between one third and one half of the mass annually discharged from the Greenland Ice Sheet into the ocean. These ice losses are increasing due to glacier acceleration and retreat, largely in response to increased heat flux from the oceans. Behaviour of Greenland's marine-terminating ('tidewater') glaciers is strongly influenced by fjord bathymetry, particularly the presence of 'pinning points' (narrow or shallow parts of fjords that encourage stability) and overdeepened basins (that encourage rapid retreat). Despite the importance of calving and submarine melting and significant advances in monitoring and understanding key processes, it is not yet possible to predict the tidewater glacier response to climatic and oceanic forcing with any confidence. The simple calving laws required for ice-sheet models do not adequately represent the complexity of calving processes. New detailed process models, however, are increasing our understanding of the key processes and are guiding the design of improved calving laws. There is thus some prospect of reaching the elusive goal of accurately predicting future tidewater glacier behaviour and associated rates of sea-level rise.

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Effect of near‐terminus subglacial hydrology on tidewater glacier submarine melt rates

Cited by 125 publications

References 37 publications

Distributed subglacial discharge drives significant submarine melt at a Greenland tidewater glacier

Distributed subglacial discharge drives significant submarine melt at a Greenland tidewater glacier

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

Glacier Calving in Greenland

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