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Chaotic variability in a model of coupled ice streams
Kolja Kypke1,2, Peter Ashwin3, Peter Ditlevsen2
1University of Guelph, Department of Mathematics and Statistics, Guelph, Canada.
Physical Review. E
|May 16, 2026
Summary
Ice streams, fast-flowing regions in ice sheets, can oscillate between build-up and surge phases due to basal thermomechanical coupling. A new model demonstrates this variability can become chaotic in branching ice stream systems.
Area of Science:
- Glaciology
- Ice sheet dynamics
- Climate science
Background:
- Ice streams are critical components of ice sheets, influencing global sea levels.
- Theories suggest basal conditions can drive oscillatory behavior in ice streams.
- Understanding ice stream dynamics is key to predicting ice sheet response to climate change.
Purpose of the Study:
- To investigate the potential for build-up/surge oscillations in coupled ice stream models.
- To explore the occurrence of chaotic variability in these systems.
- To replicate the configuration of branching ice streams found in Greenland.
Main Methods:
- Development of a simple three-coupled ice stream model.
- Simulation of thermomechanical coupling at the ice-bed interface.
- Analysis of model output for steady-flow and oscillatory behaviors, including chaotic dynamics.
Main Results:
- The model successfully replicates steady-flow conditions.
- The model exhibits build-up/surge oscillatory variability.
- Chaotic variability was observed due to nonlinear coupling of incommensurate frequencies.
Conclusions:
- Branching ice stream configurations can exhibit internal chaotic variability.
- Thermomechanical coupling at the base of ice streams can drive complex dynamic behaviors.
- This study provides a mechanism for chaotic internal variability within ice sheets.
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