Simulating the roles of crevasse routing of surface water and basal
friction on the surge evolution of Basin 3, Austfonna ice-cap

Gong, Yongmei; Zwinger, Thomas; Åström, Jan; Altena, Bas; Schellenberger, Thomas; Gladstone, Rupert; Moore, John C.

doi:10.5194/tc-2017-180

Cited by 4 publications

(4 citation statements)

References 34 publications

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“…Our model experiments do not include seasonal cycles, but the predicted impact of surface water input is consistent with the observed timing and location of rapid speed-up events during surges. In Svalbard, several studies have shown that expansion of crevasse fields during the early stages of surges has created templates for areas of flow acceleration at ablation season onset (Dunse and others, 2015; Sevestre and others, 2018; Gong and others, 2018; Benn and others, 2019). The role of surface-to-bed drainage in stabilizing the flow is illustrated by Kronebreen, a perennially fast-flowing tidewater glacier in the midst of the Svalbard surge cluster.…”

Section: Summary and Discussionmentioning

confidence: 99%

A general theory of glacier surges

et al. 2019

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We present the first general theory of glacier surging that includes both temperate and polythermal glacier surges, based on coupled mass and enthalpy budgets. Enthalpy (in the form of thermal energy and water) is gained at the glacier bed from geothermal heating plus frictional heating (expenditure of potential energy) as a consequence of ice flow. Enthalpy losses occur by conduction and loss of meltwater from the system. Because enthalpy directly impacts flow speeds, mass and enthalpy budgets must simultaneously balance if a glacier is to maintain a steady flow. If not, glaciers undergo out-of-phase mass and enthalpy cycles, manifest as quiescent and surge phases. We illustrate the theory using a lumped element model, which parameterizes key thermodynamic and hydrological processes, including surface-to-bed drainage and distributed and channelized drainage systems. Model output exhibits many of the observed characteristics of polythermal and temperate glacier surges, including the association of surging behaviour with particular combinations of climate (precipitation, temperature), geometry (length, slope) and bed properties (hydraulic conductivity). Enthalpy balance theory explains a broad spectrum of observed surging behaviour in a single framework, and offers an answer to the wider question of why the majority of glaciers do not surge.

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Section: Summary and Discussionmentioning

confidence: 99%

A general theory of glacier surges

et al. 2019

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“…Nested models would allow selective high resolution of the processes that control folding and thrusting. Likewise, hybrid models such as that of Gong et al (), which combines a finite‐element full‐Stokes thermomechanical flow model with a discrete‐element treatment of ice fracture, hold promise.…”

Section: Discussionmentioning

confidence: 99%

Structural Evolution During Cyclic Glacier Surges: 1. Structural Glaciology of Trapridge Glacier, Yukon, Canada

Hambrey

2019

JGR Earth Surface

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Interpreting the relationships among the internal processes of glaciers and their mesoscale structural products has been a long‐standing challenge for glaciologists. Trapridge Glacier is a small polythermal surge‐type valley glacier that has been studied for 40 years. It offers an opportunity to investigate the structural evolution of a glacier through a series of surges and to apply novel modeling approaches to gain physical insight as to how different structures are formed. Following the glacier's most recent slow surge, the structural attributes were documented, with emphasis on their three‐dimensional geometry and sequential development: ice stratification (S0), longitudinal foliation (S1), and associated medial moraine, folding of stratification (F1), transverse foliation (S2), thrusts (S3), and recumbent folds (F3), fractures (surface crevassing and crevasse traces; S4). Efforts to represent these structures using models of glacier flow dynamics remain at an early stage but provide informative tests of model skill and of current understanding of the processes that control structure generation. Using field interpretations as a guide to the relevant processes of formation, structures on Trapridge Glacier are compared with computer‐simulated structures for the same glacier. Modeling achieved the greatest success in simulating moraine patterns, ice stratification, longitudinal foliation, and the downglacier decrease in the density of surface crevasse traces. The least successful effort was to simulate the orientation of crevasse traces.

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“…Meltwater in crevasses has been implicated in initiating the conditions necessary for a surge, following an examination of a surge in "Basin 3" in Austfonna, an ice cap in Svalbard (Gong et al, 2018). Ice velocities began increasing in the mid-1990s as a result of basal meltwater production and crevasse formation.…”

Section: Structurally Controlled Hydrology Of Valley Glaciers and Ice Capsmentioning

confidence: 99%

Structures and Deformation in Glaciers and Ice Sheets

Jennings

Hambrey

2021

Reviews of Geophysics

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The purpose of this review is to provide a comprehensive assessment of the state of knowledge concerning the manner in which macroscopic structures evolve within glaciers, and to evaluate their meaning in terms of understanding the flow of glaciers and ice sheets. Using concepts drawn from structural geology (e.g., Fossen, 2010;Hobbs et al., 1976;Ramsay, 1967;Ramsay & Huber, 1983), attention is drawn to the similarities between glacier ice and deformed rocks. The review emphasizes those structures that can be observed at the glacier surface and considers their three-dimensional (3-D) geometry. Structures in glaciers are commonly complex and challenging to interpret, especially where several phases of deformation over-print one another. Hence, to aid the reader in the field, many of the described structures and their cross-cutting relationships are illustrated in photographs, maps, and conceptual diagrams, with examples ranging from the Arctic, through mid-latitude mountain ranges, to the Antarctic.

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Simulating the roles of crevasse routing of surface water and basal friction on the surge evolution of Basin 3, Austfonna ice-cap

Cited by 4 publications

References 34 publications

A general theory of glacier surges

A general theory of glacier surges

Structural Evolution During Cyclic Glacier Surges: 1. Structural Glaciology of Trapridge Glacier, Yukon, Canada

Structures and Deformation in Glaciers and Ice Sheets

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