Insights into ice stream dynamics through modelling their response to tidal forcing
The tidal forcing of ice streams at their ocean boundary can serve as a natural experiment to gain an insight into their dynamics and constrain the basal sliding law. A nonlinear 3-D viscoelastic full Stokes model of coupled ice stream ice shelf flow is used to investigate the response of ice stream...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2014-09-01
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| Series: | The Cryosphere |
| Online Access: | http://www.the-cryosphere.net/8/1763/2014/tc-8-1763-2014.pdf |
| Summary: | The tidal forcing of ice streams at their ocean boundary can serve as a
natural experiment to gain an insight into their dynamics and constrain the
basal sliding law. A nonlinear 3-D viscoelastic full Stokes model of
coupled ice stream ice shelf flow is used to investigate the response of ice
streams to ocean tides. In agreement with previous results based on flow-line
modelling and with a fixed grounding line position, we find that a nonlinear
basal sliding law can qualitatively reproduce long-period modulation of tidal
forcing found in field observations. In addition, we show that the inclusion
of lateral drag, or allowing the grounding line to migrate over the tidal
cycle, does not affect these conclusions. Further analysis of modelled ice
stream flow shows a varying stress-coupling length scale of boundary effects
upstream of the grounding line. We derive a viscoelastic stress-coupling
length scale from ice stream equations that depends on the forcing period and
closely agrees with model output. |
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| ISSN: | 1994-0416 1994-0424 |