Elastic dynamics and tidal migration of grounding lines modify subglacial lubrication and melting

We combine the dynamics of ice, bed, and ocean in a new elastic model for the tidal‐timescale migration of grounding lines on deformable foundations. Previous interpretations of tidal flexure using models of elastic ice shelves with fixed grounding lines were found to be inconsistent, suggesting an...

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Bibliographic Details
Published in:Geophysical research letters 2013-11, Vol.40 (22), p.5877-5881
Main Authors: Sayag, R., Worster, M. Grae
Format: Article
Language:English
Subjects:
Deformation
Dynamics
Earth sciences
Earth, ocean, space
Elastic constants
Elastic properties
Exact sciences and technology
Geophysics
Grounding
grounding line migration
High tides
Hydrology
Ice
ice sheet dynamics
ice sheet mass balance
Ice shelves
Lubrication
Marine
Melting
Migration
Oceanography
Oceans
Remote sensing
subglacial hydrology
subglacial lubrication
Tides
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Summary:We combine the dynamics of ice, bed, and ocean in a new elastic model for the tidal‐timescale migration of grounding lines on deformable foundations. Previous interpretations of tidal flexure using models of elastic ice shelves with fixed grounding lines were found to be inconsistent, suggesting an elasticity of ice that varies spatially and temporally and that is significantly smaller than measured experimentally. We argue here that with our model, a consistent, purely elastic interpretation can be made. Combining this new approach with remote‐sensing measurements, we show that the grounding line migrates several kilometers during a tidal cycle, that we can infer the effective elastic properties of the bed, and that the elastic pressure of the ice leads to a hydrological barrier near the grounding line that controls subglacial hydrology. Our findings imply that subglacial lubrication and melting induced by the ocean thermal forcing can increase substantially during high tide. Key Points Unlike previous elastic models we show consistent interpretation of observations At high tide subglacial lubrication is enhanced and acceleratesmass flux Tidal migration of grounding lines expose larger area of ice to thewarmer ocean
ISSN:0094-8276
1944-8007
DOI:10.1002/2013GL057942