HR: 1340h
AN: NG33C-0192    [Abstracts]
TI: The use of a Discrete Element Model for Granular Materials to Investigate ice Shelf Formation and Break up in Jakobshavn Isbrae
AU: * Rapp, J D
EM: jared.rapp@mso.umt.edu
AF: University of Montana Department of Computer Science, Social Science Building The University of Montana, Missoula, MT 59812-5256 United States
AU: Johnson, J V
EM: johnson@cs.umt.edu
AF: University of Montana Department of Computer Science, Social Science Building The University of Montana, Missoula, MT 59812-5256 United States
AB: The 2003 breakup of the floating portion of Jakobshavn Isbrae has resulted in more than a doubling of ice flux across the grounding line. Such dramatic changes are potentially significant for global sea level. Well validated continuum mechanics models for ice shelves are unable to reproduce the flow in the floating portion prior to break up. This is likely due to the heavily fractured nature of the region. Failure of commonly used modeling approaches motivates the use of a discrete element model for granular materials. With such a model, it is possible to study ice bergs confined in the isbrae as a granular material. Recent advances show that granular materials exhibit "jamming" behavior. Jamming is defined as the transition from liquid-like to solid-like state. The frequency of jamming events is known to be acutely sensitive to the density of the granular material. The model is used to investigate the hypothesis that the increased calving into the isbae may result in a high enough density of icebergs that a fractured shelf will form, retarding future flow. By exploring various perturbations at the grounding line and within the isbrae, conditions that lead either to breakup or formation of ice shelves are characterized.
DE: 0545 Modeling (4255)
DE: 0726 Ice sheets
DE: 0728 Ice shelves
DE: 0732 Icebergs
SC: Nonlinear Geophysics [NG]
MN: Fall Meeting 2005