Pine Island Glacier - a 3D full-Stokes model study

• Main Author: Wilkens, Nina
• Format: Thesis
• Language: unknown
• Published: 2014
• Subjects: Amundsen Sea; Antarc*; Antarctic; Ice Sheet; Ice Shelf; Pine Island Glacier
• Online Access: https://epic.awi.de/id/eprint/43458/; https://hdl.handle.net/10013/epic.49886

Mass loss from the Antarctic Ice Sheet is found to significantly contribute to eustatic sea level rise, due to a dynamic response in the system. Pine Island Glacier, a fast flowing outlet glacier in the West Antarctic Ice Sheet, is located in the Amundsen Sea Embayment Area, where the present Antarctic mass loss is concentrated. The observed mass loss in the area coincides with acceleration and thinning of the glacier, accompanied by a retreat of the grounding line, which is the line of separation between grounded and floating ice. The bed beneath the glacier lies in large parts below sea level, with the bed sloping down away from the ocean. This setting makes the glacier especially vulnerable to increasing and possibly accelerating retreat. Remote sensing techniques allow only for the surface conditions of glacial systems to be nowadays monitored over reasonable temporal and spatial scales. The conditions at the base, however, are still widely unknown, due to their inaccessibility. This poses a challenge, as basal conditions are a very important component for understanding glacier dynamics. A key technique to bridge this challenge is given by numerical modelling. In glaciological studies flow models are developed, that can either be used to solve in a prognostic manner over long time scales, being based on approximations to the full system of equations, or to solve diagnostically in high resolution for the full system, to study processes in more detail. Here we present a model of the later category, a thermo-mechanically coupled 3D full- Stokes ice flow model, which is set up to the region of Pine Island Glacier. It is solved with the finite element method, and the prismatic mesh is refined horizontally across the grounding line, where high resolution is needed. With this coupled flow model we assess the present thermal and dynamical state of the coupled ice sheet - ice shelf system. Fur- thermore, we develop a method to include measured basal properties into the formulation of the basal sliding law. We find ...