Year of Award

2013

Document Type

Thesis

Degree Type

Master of Science (MS)

Degree Name

Computer Science

Department or School/College

Department of Computer Science

Committee Chair

Jesse V. Johnson

Commitee Members

Douglas W. Raiford, Joel Harper

Keywords

rheology

Publisher

University of Montana

Abstract

Using recent measurements of the velocity of ice on the surface of Helheim Glacier, located on the south-east coast of Greenland, the variation of viscosity, a material property of the ice, is investigated. The investigation focuses on determining the value of a parameter in Glen's flow law, a constitutive equation widely used in numerical models of ice sheets. Three different approaches are used: (1) Finite differences are used in a direct approach, (2) A finite element model is used in an approach involving an inverse problem, and (3) Nonlinear least squares fits of the velocity are used. The parameter focused on, the exponent in Glen's flow law, is assigned a value of three in most ice sheet models but the results presented in this thesis suggest that the behavior of ice (at least that in the fast moving portion of Helheim Glacier) might be more accurately modeled using a significantly smaller value, 1.6.

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© Copyright 2013 Glen David Granzow