Physical conditions of fast glacier flow: 3. Seasonally-evolving ice deformation on Store Glacier, West Greenland
Temporal variations in ice sheet flow directly impact the internal structure within ice sheets through englacial deformation. Large-scale changes in the vertical stratigraphy within ice sheets have been previously conducted on centennial to millennial timescales; however, intra-annual changes in the...
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ftunivcam:oai:www.repository.cam.ac.uk:1810/288820 2024-01-14T10:07:01+01:00 Physical conditions of fast glacier flow: 3. Seasonally-evolving ice deformation on Store Glacier, West Greenland Young, tun jan Christoffersen, Poul doyle, samuel Nicholls, Keith Stewart, Craig Hubbard, Bryn Hubbard, Alun Lok, Lai Bun Bennan, Paul Luckman, Adrian Bougamont, Marion 2019-01 application/pdf https://www.repository.cam.ac.uk/handle/1810/288820 https://doi.org/10.17863/CAM.36083 eng eng Wiley-Blackwell http://dx.doi.org/10.1029/2018jf004821 Journal of Geophysical Research https://www.repository.cam.ac.uk/handle/1810/288820 doi:10.17863/CAM.36083 Attribution 4.0 International http://creativecommons.org/licenses/by/4.0/ Glacier Greenland Ice Sheet Radar Strain Article 2019 ftunivcam https://doi.org/10.17863/CAM.36083 2023-12-21T23:27:31Z Temporal variations in ice sheet flow directly impact the internal structure within ice sheets through englacial deformation. Large-scale changes in the vertical stratigraphy within ice sheets have been previously conducted on centennial to millennial timescales; however, intra-annual changes in the morphology of internal layers have yet to be explored. Over a period of two years, we use autonomous phase-sensitive radio-echo sounding (ApRES) to track the daily displacement of internal layers on Store Glacier, West Greenland to millimeter accuracy. At a site located ~30 km from the calving terminus, where the ice is ~600m thick and flows at ~700m/yr, we measure distinct seasonal variations in vertical velocities and vertical strain rates over a two-year period. Prior to the melt season (March–June), we observe increasingly non-linear englacial deformation with negative vertical strain rates (i.e. strain thinning) in the upper half of the ice column of ~0.03 a-1, whereas the ice below thickens under vertical strain reaching up to 0.16 a-1. Early in the melt season (June–July), vertical thinning gradually ceases as the glacier increasingly thickens. During late summer to midwinter (August–February), vertical thickening occurs linearly throughout the entire ice column, with strain rates averaging 0.016 a-1. We show that these complex variations are unrelated to topographic setting and localized basal slip, and hypothesize that this seasonality is driven by far-field perturbations in the glacier’s force balance, in this case generated by variations in basal hydrology near the glacier’s terminus and propagated tens of kilometers upstream through longitudinal coupling. NERC grants NE/K0058871/1 and NE/K006126/1 Article in Journal/Newspaper glacier Greenland Ice Sheet Apollo - University of Cambridge Repository Greenland Midwinter ENVELOPE(139.931,139.931,-66.690,-66.690) |
institution |
Open Polar |
collection |
Apollo - University of Cambridge Repository |
op_collection_id |
ftunivcam |
language |
English |
topic |
Glacier Greenland Ice Sheet Radar Strain |
spellingShingle |
Glacier Greenland Ice Sheet Radar Strain Young, tun jan Christoffersen, Poul doyle, samuel Nicholls, Keith Stewart, Craig Hubbard, Bryn Hubbard, Alun Lok, Lai Bun Bennan, Paul Luckman, Adrian Bougamont, Marion Physical conditions of fast glacier flow: 3. Seasonally-evolving ice deformation on Store Glacier, West Greenland |
topic_facet |
Glacier Greenland Ice Sheet Radar Strain |
description |
Temporal variations in ice sheet flow directly impact the internal structure within ice sheets through englacial deformation. Large-scale changes in the vertical stratigraphy within ice sheets have been previously conducted on centennial to millennial timescales; however, intra-annual changes in the morphology of internal layers have yet to be explored. Over a period of two years, we use autonomous phase-sensitive radio-echo sounding (ApRES) to track the daily displacement of internal layers on Store Glacier, West Greenland to millimeter accuracy. At a site located ~30 km from the calving terminus, where the ice is ~600m thick and flows at ~700m/yr, we measure distinct seasonal variations in vertical velocities and vertical strain rates over a two-year period. Prior to the melt season (March–June), we observe increasingly non-linear englacial deformation with negative vertical strain rates (i.e. strain thinning) in the upper half of the ice column of ~0.03 a-1, whereas the ice below thickens under vertical strain reaching up to 0.16 a-1. Early in the melt season (June–July), vertical thinning gradually ceases as the glacier increasingly thickens. During late summer to midwinter (August–February), vertical thickening occurs linearly throughout the entire ice column, with strain rates averaging 0.016 a-1. We show that these complex variations are unrelated to topographic setting and localized basal slip, and hypothesize that this seasonality is driven by far-field perturbations in the glacier’s force balance, in this case generated by variations in basal hydrology near the glacier’s terminus and propagated tens of kilometers upstream through longitudinal coupling. NERC grants NE/K0058871/1 and NE/K006126/1 |
format |
Article in Journal/Newspaper |
author |
Young, tun jan Christoffersen, Poul doyle, samuel Nicholls, Keith Stewart, Craig Hubbard, Bryn Hubbard, Alun Lok, Lai Bun Bennan, Paul Luckman, Adrian Bougamont, Marion |
author_facet |
Young, tun jan Christoffersen, Poul doyle, samuel Nicholls, Keith Stewart, Craig Hubbard, Bryn Hubbard, Alun Lok, Lai Bun Bennan, Paul Luckman, Adrian Bougamont, Marion |
author_sort |
Young, tun jan |
title |
Physical conditions of fast glacier flow: 3. Seasonally-evolving ice deformation on Store Glacier, West Greenland |
title_short |
Physical conditions of fast glacier flow: 3. Seasonally-evolving ice deformation on Store Glacier, West Greenland |
title_full |
Physical conditions of fast glacier flow: 3. Seasonally-evolving ice deformation on Store Glacier, West Greenland |
title_fullStr |
Physical conditions of fast glacier flow: 3. Seasonally-evolving ice deformation on Store Glacier, West Greenland |
title_full_unstemmed |
Physical conditions of fast glacier flow: 3. Seasonally-evolving ice deformation on Store Glacier, West Greenland |
title_sort |
physical conditions of fast glacier flow: 3. seasonally-evolving ice deformation on store glacier, west greenland |
publisher |
Wiley-Blackwell |
publishDate |
2019 |
url |
https://www.repository.cam.ac.uk/handle/1810/288820 https://doi.org/10.17863/CAM.36083 |
long_lat |
ENVELOPE(139.931,139.931,-66.690,-66.690) |
geographic |
Greenland Midwinter |
geographic_facet |
Greenland Midwinter |
genre |
glacier Greenland Ice Sheet |
genre_facet |
glacier Greenland Ice Sheet |
op_relation |
https://www.repository.cam.ac.uk/handle/1810/288820 doi:10.17863/CAM.36083 |
op_rights |
Attribution 4.0 International http://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.17863/CAM.36083 |
_version_ |
1788061427610681344 |