Basal traction mainly dictated by hard-bed physics over grounded regions of Greenland
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Published:2021-03-22
Issue:3
Volume:15
Page:1435-1451
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ISSN:1994-0424
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Container-title:The Cryosphere
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language:en
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Short-container-title:The Cryosphere
Author:
Maier NathanORCID, Gimbert FlorentORCID, Gillet-Chaulet FabienORCID, Gilbert Adrien
Abstract
Abstract. On glaciers and ice sheets, identifying the relationship between
velocity and traction is critical to constrain the bed physics that controls
ice flow. Yet in Greenland, these relationships remain unquantified. We
determine the spatial relationship between velocity and traction in all
eight major drainage catchments of Greenland. The basal traction is
estimated using three different methods over large grid cells to minimize
interpretation biases associated with unconstrained rheologic parameters
used in numerical inversions. We find the relationships are consistent with
our current understanding of basal physics in each catchment. We identify
catchments that predominantly show Mohr–Coulomb-like behavior typical of
deforming beds or significant cavitation, as well as catchments that
predominantly show rate-strengthening behavior typical of Weertman-type
hard-bed physics. Overall, the traction relationships suggest that the flow
field and surface geometry of the grounded regions in Greenland is mainly
dictated by Weertman-type hard-bed physics up to velocities of approximately
450 m yr−1, except within the Northeast Greenland Ice Stream and areas near
floatation. Depending on the catchment, behavior of the fastest-flowing ice
(∼ 1000 m yr−1) directly inland from marine-terminating outlets
exhibits Weertman-type rate strengthening, Mohr–Coulomb-like behavior, or is
not confidently resolved given our methodology. Given the complex basal
boundary across Greenland, the relationships are captured reasonably well by
simple traction laws which provide a parameterization that can be used to
model ice dynamics at large scales. The results and analysis serve as a
first constraint on the physics of basal motion over the grounded regions of
Greenland and provide unique insight into future dynamics and
vulnerabilities in a warming climate.
Publisher
Copernicus GmbH
Subject
Earth-Surface Processes,Water Science and Technology
Reference76 articles.
1. Alley, R. B. and Joughin, I.: Modeling Ice-Sheet Flow, Science, 336,
551–552, 2012. 2. Bons, P. D., Kleiner, T., Llorens, M., Prior, D. J., Sachau, T., Weikusat,
I., and Jansen, D.: Greenland Ice Sheet: Higher nonlinearity of ice flow
significantly reduces estimated basal motion, Geophys. Res. Lett.,
45, 6542–6548, 2018. 3. Booth, A. D., Clark, R. A., Kulessa, B., Murray, T., Carter, J., Doyle, S., and Hubbard, A.: Thin-layer effects in glaciological seismic amplitude-versus-angle (AVA) analysis: implications for characterising a subglacial till unit, Russell Glacier, West Greenland, The Cryosphere, 6, 909–922, https://doi.org/10.5194/tc-6-909-2012, 2012. 4. Bougamont, M., Christoffersen, P., Hubbard, A., Fitzpatrick, A., Doyle, S., and Carter, S.: Sensitive response of the Greenland Ice Sheet to surface melt drainage over a soft bed, Nat. Commun., 5, 19, https://doi.org/10.1038/ncomms6052, 2014. 5. Carr, J. R., Vieli, A., Stokes, C., Jamieson, S., Palmer, S.,
Christoffersen, P., Dowdeswell, J., Nick, F., Blankenship, D. D., and Young,
D. A.: Basal topographic controls on rapid retreat of Humboldt Glacier,
northern Greenland, J. Glaciol., 61, 137–150, 2015.
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