A shallow approximation for ice streams sliding over strong beds

Ice streams are regions of rapid ice sheet flow characterised by a high degree of sliding over a deforming bed. The shallow shelf approximation (SSA) provides a convenient way to obtain closed-form approximations of the velocity and flux in a rapidly sliding ice stream when the basal drag is much le...

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Bibliographic Details
Published in:Journal of glaciology 2023-12, Vol.69 (278), p.1634-1645
Main Authors: Warburton, Katarzyna L. P., Hewitt, Duncan R., Meyer, Colin R., Neufeld, Jerome A.
Format: Article
Language:English
Subjects:
Approximation
Closed form solutions
Deformation
Drag
Exact solutions
Geometry
glacial rheology
Glaciation
glacier flow
Ice
ice dynamics
Ice formation
Ice sheets
Ice streams
Laminar flow
Rheology
Rivers
Shear strength
Shear stress
Sliding
Slumping
Streams
Topography
Velocity
Viscosity
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Summary:Ice streams are regions of rapid ice sheet flow characterised by a high degree of sliding over a deforming bed. The shallow shelf approximation (SSA) provides a convenient way to obtain closed-form approximations of the velocity and flux in a rapidly sliding ice stream when the basal drag is much less than the driving stress. However, the validity of the SSA approximation breaks down when the magnitude of the basal drag increases. Here we find a more accurate expression for the velocity and flux in this transitional regime before vertical deformation fully dominates, in agreement with numerical results. The closed-form expressions we derive can be incorporated into wider modelling efforts to yield a better characterisation of ice stream dynamics, and inform the use of the SSA in large-scale simulations.
ISSN:0022-1430
1727-5652
DOI:10.1017/jog.2023.47