Behaviour of the Grounding Lines of Unconfined Marine Ice Sheets in Low Driving/Basal Stress Regime
Abstract
Simple theories of ice sheet and shelf flow have led to the marine ice sheet instability (MISI) hypothesis, which regards grounding lines on up-sloping beds as unconditionally unstable. While these theories suppose large basal and driving stresses, many present-day ice streams that transport ice from the interior of West Antarctic Ice Sheet into the surrounding oceans experience low driving stresses. Using analytical and numerical solutions of a widely-used, vertically-integrated ice flow model, we show that marine ice sheets in low driving/basal stress regimes exhibit different behaviours from those with high driving and basal stresses. We find that form drag plays a significant role in the dynamics of ice streams in these low driving/basal stress regimes. As a result, their grounding lines can achieve stable steady-state positions on up-sloping beds. Our results question the applicability of the MISI hypothesis to unconfined marine ice sheets in regimes of low driving/basal stress.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.C33A..04S
- Keywords:
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- 0726 Ice sheets;
- CRYOSPHEREDE: 0728 Ice shelves;
- CRYOSPHEREDE: 0730 Ice streams;
- CRYOSPHEREDE: 0798 Modeling;
- CRYOSPHERE