Grounding-line flux formula applied as a flux condition in numerical simulations fails for buttressed Antarctic ice streams
<p>Currently, several large-scale ice-flow models impose a condition on ice flux across grounding lines using an analytically motivated parameterisation of grounding-line flux. It has been suggested that employing this analytical expression alleviates the need for highly resolved computatio...
| Published in: | The Cryosphere |
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| Main Authors: | , , |
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2018-10-01
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| Online Access: | https://www.the-cryosphere.net/12/3229/2018/tc-12-3229-2018.pdf |
| Summary: | <p>Currently, several large-scale ice-flow models impose a condition on ice flux
across grounding lines using an analytically motivated parameterisation of
grounding-line flux. It has been suggested that employing this analytical
expression alleviates the need for highly resolved computational domains
around grounding lines of marine ice sheets. While the analytical flux
formula is expected to be accurate in an unbuttressed flow-line setting, its
validity has hitherto not been assessed for complex and realistic geometries
such as those of the Antarctic Ice Sheet. Here the accuracy of this
analytical flux formula is tested against an optimised ice flow model that
uses a highly resolved computational mesh around the Antarctic grounding
lines. We find that when applied to the Antarctic Ice Sheet the analytical
expression provides inaccurate estimates of ice fluxes for almost all
grounding lines. Furthermore, in many instances direct application of the
analytical formula gives rise to unphysical complex-valued ice fluxes. We
conclude that grounding lines of the Antarctic Ice Sheet are, in general, too
highly buttressed for the analytical parameterisation to be of practical
value for the calculation of grounding-line fluxes.</p> |
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| ISSN: | 1994-0416 1994-0424 |