Consistent generation of ice-streams via thermo-viscous instabilities modulated by membrane stresses

Accurate computation of ice‐stream location and dynamics is a key aspiration for theoretical glaciology. Ice‐sheet models with thermo‐viscous coupling have been shown to exhibit stream‐like instabilities using shallow‐ice approximation mechanics, but the location and width of these streams depends o...

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Published inGeophysical research letters Vol. 36; no. 6; pp. L06502 - n/a
Main Author Hindmarsh, Richard C. A.
Format Journal Article
LanguageEnglish
Published Washington, DC American Geophysical Union 01.03.2009
Blackwell Publishing Ltd
John Wiley & Sons, Inc
Subjects
Computational Geophysics
Cryosphere
Earth sciences
Earth, ocean, space
Exact sciences and technology
Geophysics
Glaciology
High performance computing
Ice
ice stream
Ice streams
instability
Modeling
Numerical solutions
Thermal regime
Thermodynamics
polar regions
Antarctica
ice stream
instability
glaciology
stress
models
streams
exhibits
ice
Ice stream
ice streams
coupling
dynamics
ice sheets
Northern Hemisphere
Feedback
Membrane
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Summary:Accurate computation of ice‐stream location and dynamics is a key aspiration for theoretical glaciology. Ice‐sheet models with thermo‐viscous coupling have been shown to exhibit stream‐like instabilities using shallow‐ice approximation mechanics, but the location and width of these streams depends on the numerical implementation and are not unique. We present results from thermo‐viscously coupled ice‐sheet models incorporating membrane stresses. Spontaneous generation of fast‐flowing linear features still occurs under certain parameter regimes, with computed stream widths between 20 km to 100 km, comparable with observations. These features are maintained as the grid‐size is decreased. The thermo‐viscous feedback mechanism that generates ice‐streams under the shallow ice approximation still operates, now selecting a unique stream size. Computations of thermo‐viscous ice flows should include membrane stresses when the bed is approximately flat, e.g. parts of Antarctica and former ice‐sheets of the Northern hemisphere. Previous calculations of spontaneous ice‐stream generation using the shallow ice approximation should be reassessed.
Bibliography:ark:/67375/WNG-J73WGG15-B
istex:6E24716AB3A97A3C6C23ACCA92DA964393C8845B
ArticleID:2008GL036877
ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
content type line 23
ISSN:0094-8276
1944-8007
DOI:10.1029/2008GL036877