Turbulent plumes from a glacier terminus melting in a stratified ocean

Magorrian, Samuel; Wells, Andrew

doi:10.1002/2015jc011160

Cited by 40 publications

(65 citation statements)

References 59 publications

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“…12). Magorrian and Wells (2016) covered the case for small discharge. The reasoning in this Appendix provides a unifying solution for small and large discharge with the LP model applied at tidewater glacier and glacier with long floating tongues.…”

Section: Discussionmentioning

confidence: 99%

“…Since the temperature of the ocean is projected to increase with global warming, dependence of melt rate on ocean temperature is crucial to study glacier response to global warm- ing. Previous experiments with 2-D and 3-D ocean models, as well as analytical solutions (Jenkins, 2011;Sciascia et al, 2013;Carroll et al, 2015;Jenkins, 2011;Magorrian and Wells, 2016;Slater et al, 2016;Carroll et al, 2015), demonstrated the behavior of the cumulative melt rate as a function of the ambient temperature T a . Figure 8 shows for both plume models the dependence of cumulative melt rate on temperature in a well-mixed ambient environment for different values of subglacial discharge.…”

Section: Ambient Temperature and Stratificationmentioning

confidence: 93%

“…(5) in Slater et al (2016), with the addition of the basal drag term. These balance solutions are only valid in the vicinity of the grounding line and velocity might then differ substantially as the plume develops, especially for small subglacial discharge (e.g., Magorrian and Wells, 2016). A more detailed discussion and a full, depth-dependent solution for the LP model are given in the Appendix.…”

Section: Initial Conditions and Balance Velocitymentioning

confidence: 99%

“…5). This value represents background melt rate, or "melt-driven convection", which does not depend on discharge and can be representative for winter melt rate when subglacial discharge is very small (Magorrian and Wells, 2016).…”

Section: Subglacial Dischargementioning

confidence: 99%

“…10b). The dependence of melt to the slope of the glacier for small discharges has been derived by Magorrian and Wells (2016). A glacier with a long floating tongue, and therefore a small angle, has a smaller average melt rate than a tidewater glacier but a higher cumulative melt rate (Fig.…”

Section: Glacier Front Angle For the Line Plumementioning

confidence: 99%

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Simple models for the simulation of submarine melt for a Greenland glacial system model

2018

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Abstract. Two hundred marine-terminating Greenland outlet glaciers deliver more than half of the annually accumulated ice into the ocean and have played an important role in the Greenland ice sheet mass loss observed since the mid1990s. Submarine melt may play a crucial role in the mass balance and position of the grounding line of these outlet glaciers. As the ocean warms, it is expected that submarine melt will increase, potentially driving outlet glaciers retreat and contributing to sea level rise. Projections of the future contribution of outlet glaciers to sea level rise are hampered by the necessity to use models with extremely high resolution of the order of a few hundred meters. That requirement in not only demanded when modeling outlet glaciers as a stand alone model but also when coupling them with highresolution 3-D ocean models. In addition, fjord bathymetry data are mostly missing or inaccurate (errors of several hundreds of meters), which questions the benefit of using computationally expensive 3-D models for future predictions. Here we propose an alternative approach built on the use of a computationally efficient simple model of submarine melt based on turbulent plume theory. We show that such a simple model is in reasonable agreement with several available modeling studies. We performed a suite of experiments to analyze sensitivity of these simple models to model parameters and climate characteristics. We found that the computationally cheap plume model demonstrates qualitatively similar behavior as 3-D general circulation models. To match results of the 3-D models in a quantitative manner, a scaling factor of the order of 1 is needed for the plume models. We applied this approach to model submarine melt for six representative Greenland glaciers and found that the application of a line plume can produce submarine melt compatible with observational data. Our results show that the line plume model is more appropriate than the cone plume model for simulating the average submarine melting of real glaciers in Greenland.

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Section: Discussionmentioning

confidence: 99%

Section: Ambient Temperature and Stratificationmentioning

confidence: 93%

Section: Initial Conditions and Balance Velocitymentioning

confidence: 99%

Section: Subglacial Dischargementioning

confidence: 99%

Section: Glacier Front Angle For the Line Plumementioning

confidence: 99%

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Simple models for the simulation of submarine melt for a Greenland glacial system model

2018

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A model for tidewater glacier undercutting by submarine melting

Slater

Nienow

Goldberg

et al. 2017

Geophysical Research Letters

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Dynamic change at the marine‐terminating margins of the Greenland Ice Sheet may be initiated by the ocean, particularly where subglacial runoff drives vigorous ice‐marginal plumes and rapid submarine melting. Here we model submarine melt‐driven undercutting of tidewater glacier termini, simulating a process which is key to understanding ice‐ocean coupling. Where runoff emerges from broad subglacial channels we find that undercutting has only a weak impact on local submarine melt rate but increases total ablation by submarine melting due to the larger submerged ice surface area. Thus, the impact of melting is determined not only by the melt rate magnitude but also by the slope of the ice‐ocean interface. We suggest that the most severe undercutting occurs at the maximum height in the fjord reached by the plume, likely promoting calving of ice above. It remains unclear, however, whether undercutting proceeds sufficiently rapidly to influence calving at Greenland's fastest‐flowing glaciers.

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Linking Overturning, Recirculation, and Melt in Glacial Fjords

Zhao

Stewart

McWilliams

2021

Preprint

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Fjord circulation modulates the connection between marine-terminating glaciers and the ocean currents offshore. These fjords exhibit both overturning and horizontal recirculations, which are driven by water mass transformation at the head of the fjord via subglacial discharge plumes and distributed meltwater plumes. However, little is known about the interaction between the 3D fjord circulation and glacial melt and how relevant fjord properties influence them. In this study, high-resolution numerical simulations of idealized glacial fjords demonstrate that recirculation strength controls melt, which feeds back on overturning and recirculation. The overturning circulation strength is well predicted by existed plume models for face-wide melt and subglacial discharge, while relationships between the overturning, recirculation, and melt rate are well predicted by vorticity balance, reduced-order melt parameterizations, and empirical scaling arguments. These theories allow improved predictions of fjord overturning, recirculation, and glacial melt by taking intrafjord dynamics into account.

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Turbulent plumes from a glacier terminus melting in a stratified ocean

Cited by 40 publications

References 59 publications

Simple models for the simulation of submarine melt for a Greenland glacial system model

Simple models for the simulation of submarine melt for a Greenland glacial system model

A model for tidewater glacier undercutting by submarine melting

Linking Overturning, Recirculation, and Melt in Glacial Fjords

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