An Investigation of Viscosity Using Measured Velocities on Helheim Glacier
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...
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| Format: | Thesis |
| Language: | unknown |
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University of Montana
2013
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| Online Access: | https://scholarworks.umt.edu/etd/4184 https://scholarworks.umt.edu/context/etd/article/5203/viewcontent/thesis.pdf |
| Summary: | 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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