Modelling the migration of ice stream margins ...

• Main Author: Haseloff, Marianne
• Format: Text
• Language: English
• Published: University of British Columbia 2015
• Subjects: Antarc*; Antarctic; Ice Sheet
• Online Access: https://dx.doi.org/10.14288/1.0166470; https://doi.library.ubc.ca/10.14288/1.0166470

The Siple Coast ice streams are long, narrow bands of ice within the Antarctic ice sheet. They move significantly faster than the surrounding ice ridges, and therefore discharge significantly more ice. Observations suggest that their fast flow is due to sliding along a water-saturated bed, while the bed of the neighbouring ridges generally appears to be frozen. The ice stream velocities and widths vary on decadal to centennial time scales, and these variations include the migration of the ice stream margins, where the fast flow slows down to the speed of the surrounding ice. In this thesis I show that conventional thin film models, which are used to calculate the evolution of ice sheets on continental scales, are only able to reproduce the inwards migration of ice stream margins and the subsequent shutdown of an ice stream. These processes are the result of an insufficient heat dissipation and freezing at the bed. Conversely, I find that the widening of ice streams into regions where the bed is frozen can ...