Basal traction mainly dictated by hard-bed physics over grounded regions of Greenland
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 dr...
Published in: | The Cryosphere |
---|---|
Main Authors: | , , , |
Format: | Text |
Language: | English |
Published: |
2021
|
Subjects: | |
Online Access: | https://doi.org/10.5194/tc-15-1435-2021 https://tc.copernicus.org/articles/15/1435/2021/ |
id |
ftcopernicus:oai:publications.copernicus.org:tc86680 |
---|---|
record_format |
openpolar |
spelling |
ftcopernicus:oai:publications.copernicus.org:tc86680 2023-05-15T16:24:32+02:00 Basal traction mainly dictated by hard-bed physics over grounded regions of Greenland Maier, Nathan Gimbert, Florent Gillet-Chaulet, Fabien Gilbert, Adrien 2021-03-22 application/pdf https://doi.org/10.5194/tc-15-1435-2021 https://tc.copernicus.org/articles/15/1435/2021/ eng eng doi:10.5194/tc-15-1435-2021 https://tc.copernicus.org/articles/15/1435/2021/ eISSN: 1994-0424 Text 2021 ftcopernicus https://doi.org/10.5194/tc-15-1435-2021 2021-03-29T16:22:18Z 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. Text Greenland Copernicus Publications: E-Journals Greenland Weertman ENVELOPE(-67.753,-67.753,-66.972,-66.972) The Cryosphere 15 3 1435 1451 |
institution |
Open Polar |
collection |
Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
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. |
format |
Text |
author |
Maier, Nathan Gimbert, Florent Gillet-Chaulet, Fabien Gilbert, Adrien |
spellingShingle |
Maier, Nathan Gimbert, Florent Gillet-Chaulet, Fabien Gilbert, Adrien Basal traction mainly dictated by hard-bed physics over grounded regions of Greenland |
author_facet |
Maier, Nathan Gimbert, Florent Gillet-Chaulet, Fabien Gilbert, Adrien |
author_sort |
Maier, Nathan |
title |
Basal traction mainly dictated by hard-bed physics over grounded regions of Greenland |
title_short |
Basal traction mainly dictated by hard-bed physics over grounded regions of Greenland |
title_full |
Basal traction mainly dictated by hard-bed physics over grounded regions of Greenland |
title_fullStr |
Basal traction mainly dictated by hard-bed physics over grounded regions of Greenland |
title_full_unstemmed |
Basal traction mainly dictated by hard-bed physics over grounded regions of Greenland |
title_sort |
basal traction mainly dictated by hard-bed physics over grounded regions of greenland |
publishDate |
2021 |
url |
https://doi.org/10.5194/tc-15-1435-2021 https://tc.copernicus.org/articles/15/1435/2021/ |
long_lat |
ENVELOPE(-67.753,-67.753,-66.972,-66.972) |
geographic |
Greenland Weertman |
geographic_facet |
Greenland Weertman |
genre |
Greenland |
genre_facet |
Greenland |
op_source |
eISSN: 1994-0424 |
op_relation |
doi:10.5194/tc-15-1435-2021 https://tc.copernicus.org/articles/15/1435/2021/ |
op_doi |
https://doi.org/10.5194/tc-15-1435-2021 |
container_title |
The Cryosphere |
container_volume |
15 |
container_issue |
3 |
container_start_page |
1435 |
op_container_end_page |
1451 |
_version_ |
1766013030011764736 |