Processes controlling the downstream evolution of ice rheology in glacier shear margins: case study on Rutford Ice Stream, West Antarctica
Ice rheology governs how glaciers flow and respond to environmental change. The rheology of glacier ice evolves in response to a variety of mechanisms, including damage, heating, melting and the development of crystalline fabric. The relative contributions of these rheological mechanisms are not wel...
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ftnerc:oai:nora.nerc.ac.uk:520981 2023-05-15T13:49:35+02:00 Processes controlling the downstream evolution of ice rheology in glacier shear margins: case study on Rutford Ice Stream, West Antarctica Minchew, Brent M. Meyer, Colin R. Robel, Alexander A. Gudmundsson, G. Hilmar Simons, Mark 2018-08 text http://nora.nerc.ac.uk/id/eprint/520981/ https://nora.nerc.ac.uk/id/eprint/520981/1/Minchew1.pdf https://doi.org/10.1017/jog.2018.47 en eng Cambridge University Press https://nora.nerc.ac.uk/id/eprint/520981/1/Minchew1.pdf Minchew, Brent M.; Meyer, Colin R.; Robel, Alexander A.; Gudmundsson, G. Hilmar orcid:0000-0003-4236-5369 Simons, Mark. 2018 Processes controlling the downstream evolution of ice rheology in glacier shear margins: case study on Rutford Ice Stream, West Antarctica. Journal of Glaciology, 64 (246). 583-594. https://doi.org/10.1017/jog.2018.47 <https://doi.org/10.1017/jog.2018.47> cc_by_4 CC-BY Publication - Article PeerReviewed 2018 ftnerc https://doi.org/10.1017/jog.2018.47 2023-02-04T19:47:06Z Ice rheology governs how glaciers flow and respond to environmental change. The rheology of glacier ice evolves in response to a variety of mechanisms, including damage, heating, melting and the development of crystalline fabric. The relative contributions of these rheological mechanisms are not well understood. Using remotely sensed data and physical models, we decouple the influence of each of the aforementioned mechanisms along the margins of Rutford Ice Stream, a laterally confined outlet glacier in West Antarctica. We show that fabric is an important control on ice rheology in the shear margins, with an inferred softening effect consistent with a single-maximum fabric. Fabric evolves to steady state near the onset of streaming flow, and ice progressively softens downstream almost exclusively due to shear heating. The rate of heating is sensitive to local shear strain rates, which respond to local changes in bed topography as ice is squeezed through the basal trough. The impact of shear heating on the downstream evolution of ice rheology in a laterally confined glacier suggests that the thermoviscous feedback – wherein faster ice flow leads to higher rates of shear heating, further softening the ice – is a fundamental control on glacier dynamics. Article in Journal/Newspaper Antarc* Antarctica Antarctica Journal Ice Stream A Journal of Glaciology Rutford Ice Stream West Antarctica Natural Environment Research Council: NERC Open Research Archive West Antarctica Rutford ENVELOPE(-85.300,-85.300,-78.600,-78.600) Rutford Ice Stream ENVELOPE(-80.000,-80.000,-79.167,-79.167) Journal of Glaciology 64 246 583 594 |
institution |
Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
English |
description |
Ice rheology governs how glaciers flow and respond to environmental change. The rheology of glacier ice evolves in response to a variety of mechanisms, including damage, heating, melting and the development of crystalline fabric. The relative contributions of these rheological mechanisms are not well understood. Using remotely sensed data and physical models, we decouple the influence of each of the aforementioned mechanisms along the margins of Rutford Ice Stream, a laterally confined outlet glacier in West Antarctica. We show that fabric is an important control on ice rheology in the shear margins, with an inferred softening effect consistent with a single-maximum fabric. Fabric evolves to steady state near the onset of streaming flow, and ice progressively softens downstream almost exclusively due to shear heating. The rate of heating is sensitive to local shear strain rates, which respond to local changes in bed topography as ice is squeezed through the basal trough. The impact of shear heating on the downstream evolution of ice rheology in a laterally confined glacier suggests that the thermoviscous feedback – wherein faster ice flow leads to higher rates of shear heating, further softening the ice – is a fundamental control on glacier dynamics. |
format |
Article in Journal/Newspaper |
author |
Minchew, Brent M. Meyer, Colin R. Robel, Alexander A. Gudmundsson, G. Hilmar Simons, Mark |
spellingShingle |
Minchew, Brent M. Meyer, Colin R. Robel, Alexander A. Gudmundsson, G. Hilmar Simons, Mark Processes controlling the downstream evolution of ice rheology in glacier shear margins: case study on Rutford Ice Stream, West Antarctica |
author_facet |
Minchew, Brent M. Meyer, Colin R. Robel, Alexander A. Gudmundsson, G. Hilmar Simons, Mark |
author_sort |
Minchew, Brent M. |
title |
Processes controlling the downstream evolution of ice rheology in glacier shear margins: case study on Rutford Ice Stream, West Antarctica |
title_short |
Processes controlling the downstream evolution of ice rheology in glacier shear margins: case study on Rutford Ice Stream, West Antarctica |
title_full |
Processes controlling the downstream evolution of ice rheology in glacier shear margins: case study on Rutford Ice Stream, West Antarctica |
title_fullStr |
Processes controlling the downstream evolution of ice rheology in glacier shear margins: case study on Rutford Ice Stream, West Antarctica |
title_full_unstemmed |
Processes controlling the downstream evolution of ice rheology in glacier shear margins: case study on Rutford Ice Stream, West Antarctica |
title_sort |
processes controlling the downstream evolution of ice rheology in glacier shear margins: case study on rutford ice stream, west antarctica |
publisher |
Cambridge University Press |
publishDate |
2018 |
url |
http://nora.nerc.ac.uk/id/eprint/520981/ https://nora.nerc.ac.uk/id/eprint/520981/1/Minchew1.pdf https://doi.org/10.1017/jog.2018.47 |
long_lat |
ENVELOPE(-85.300,-85.300,-78.600,-78.600) ENVELOPE(-80.000,-80.000,-79.167,-79.167) |
geographic |
West Antarctica Rutford Rutford Ice Stream |
geographic_facet |
West Antarctica Rutford Rutford Ice Stream |
genre |
Antarc* Antarctica Antarctica Journal Ice Stream A Journal of Glaciology Rutford Ice Stream West Antarctica |
genre_facet |
Antarc* Antarctica Antarctica Journal Ice Stream A Journal of Glaciology Rutford Ice Stream West Antarctica |
op_relation |
https://nora.nerc.ac.uk/id/eprint/520981/1/Minchew1.pdf Minchew, Brent M.; Meyer, Colin R.; Robel, Alexander A.; Gudmundsson, G. Hilmar orcid:0000-0003-4236-5369 Simons, Mark. 2018 Processes controlling the downstream evolution of ice rheology in glacier shear margins: case study on Rutford Ice Stream, West Antarctica. Journal of Glaciology, 64 (246). 583-594. https://doi.org/10.1017/jog.2018.47 <https://doi.org/10.1017/jog.2018.47> |
op_rights |
cc_by_4 |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1017/jog.2018.47 |
container_title |
Journal of Glaciology |
container_volume |
64 |
container_issue |
246 |
container_start_page |
583 |
op_container_end_page |
594 |
_version_ |
1766251811072638976 |