Modelling calving front dynamics using a level-set method: application to Jakobshavn Isbræ, West Greenland
Calving is a major mechanism of ice discharge of the Antarctic and Greenland ice sheets, and a change in calving front position affects the entire stress regime of marine terminating glaciers. The representation of calving front dynamics in a 2-D or 3-D ice sheet model remains non-trivial. Here, we...
Main Authors: | , , , , , , |
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Format: | Article |
Language: | English |
Published: |
Copernicus Publications
2016-03-01
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Series: | The Cryosphere |
Online Access: | http://www.the-cryosphere.net/10/497/2016/tc-10-497-2016.pdf |
Summary: | Calving is a major mechanism of ice discharge of the Antarctic and Greenland
ice sheets, and a change in calving front position
affects the entire stress regime of marine terminating glaciers. The
representation of calving front dynamics in a 2-D or 3-D ice sheet
model remains non-trivial. Here, we present the theoretical and technical
framework for a level-set method, an implicit boundary tracking scheme, which
we implement into the Ice Sheet System Model (ISSM). This scheme allows us to
study the dynamic response of a drainage basin to user-defined calving rates.
We apply the method to Jakobshavn Isbræ, a major marine terminating
outlet glacier of the West Greenland Ice Sheet. The model robustly reproduces
the high sensitivity of the glacier to calving, and we find that enhanced
calving triggers significant acceleration of the ice stream. Upstream
acceleration is sustained through a combination of mechanisms. However, both
lateral stress and ice influx stabilize the ice stream. This study provides
new insights into the ongoing changes occurring at Jakobshavn Isbræ and
emphasizes that the incorporation of moving boundaries and dynamic lateral
effects, not captured in flow-line models, is key for realistic model
projections of sea level rise on centennial timescales. |
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ISSN: | 1994-0416 1994-0424 |