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Descripción
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| Amundsenisen is an icefield, 80 km2 in area, located in Southern Spitsbergen, Svalbard. Radioecho sounding measurements suggest a mostly temperate ice body, though at certain locations there are cold ice patches at the upper part of the ice column. The radar data also show high intensity returns from a nearly flat basal reflector at four zones, all of them with ice thickness greater than 500 m. These reflections suggest possible subglacial lakes. To determine whether basal liquid water is compatible with current pressure and temperature conditions, we aim to apply a thermo-mechanical model with a free boundary at the bed defined as solution of a Stefan problem for the interface ice-subglacial lake. The complexity of the problem suggests the use of a bi-dimensional model, but this requires that well-defined flowlines across the zones with suspected subglacial lakes are available. The main goal of the present contribution is to define these flowlines, and their corresponding velocity fields, from the solution of a threedimensional full-Stokes dynamical model. We are mostly interested in the plateau zone of the icefield, so we introduce artificial vertical boundaries at the heads of the main outlet glaciers draining Amundsenisen. At these boundaries we set velocity boundary conditions based on field measurements. Only velocities at the centres of the outlets are available. The velocities at depth are calculated according to a SIA velocity-depth profile, and those at the rest of the transverse section are computed following Nye's (1952) model. The upper boundary is a traction-free boundary. Because the basal ice is temperate, and due to the lack of further information on basal conditions, we set sliding boundary conditions dependent on the hydraulic potential. | |
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Internacional
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Si |
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Nombre congreso
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Workshop on the Dynamics and Mass Budget of Arctic Glaciers & the IASC Network on Arctic Glaciology Annual Meeting |
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Tipo de participación
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960 |
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Lugar del congreso
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Zieleneic, Poland |
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Revisores
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Si |
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ISBN o ISSN
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DOI
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Fecha inicio congreso
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09/01/2012 |
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Fecha fin congreso
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13/01/2012 |
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Desde la página
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44 |
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Hasta la página
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46 |
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Título de las actas
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The Dynamics and Mass Budget of Arctic Glaciers |