Effects of ice deformation on Röthlisberger channels and implications for transitions in subglacial hydrology
ABSTRACT Along the base of glaciers and ice sheets, the sliding of ice over till depends critically on water drainage. In locations where drainage occurs through Röthlisberger channels, the effective pressure along the base of the ice increases and can lead to a strengthening of the bed, which reduc...
Published in: | Journal of Glaciology |
---|---|
Main Authors: | , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Cambridge University Press (CUP)
2016
|
Subjects: | |
Online Access: | http://dx.doi.org/10.1017/jog.2016.65 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143016000654 |
id |
crcambridgeupr:10.1017/jog.2016.65 |
---|---|
record_format |
openpolar |
spelling |
crcambridgeupr:10.1017/jog.2016.65 2024-09-15T18:15:39+00:00 Effects of ice deformation on Röthlisberger channels and implications for transitions in subglacial hydrology MEYER, COLIN R. FERNANDES, MATHEUS C. CREYTS, TIMOTHY T. RICE, JAMES R. 2016 http://dx.doi.org/10.1017/jog.2016.65 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143016000654 en eng Cambridge University Press (CUP) http://creativecommons.org/licenses/by/4.0/ Journal of Glaciology volume 62, issue 234, page 750-762 ISSN 0022-1430 1727-5652 journal-article 2016 crcambridgeupr https://doi.org/10.1017/jog.2016.65 2024-08-14T04:02:27Z ABSTRACT Along the base of glaciers and ice sheets, the sliding of ice over till depends critically on water drainage. In locations where drainage occurs through Röthlisberger channels, the effective pressure along the base of the ice increases and can lead to a strengthening of the bed, which reduces glacier sliding. The formation of Röthlisberger channels depends on two competing effects: (1) melting from turbulent dissipation opens the channel walls and (2) creep flow driven by the weight of the overlying ice closes the channels radially inward. Variation in downstream ice velocity along the channel axis, referred to as an antiplane shear strain rate, decreases the effective viscosity. The softening of the ice increases creep closure velocities. In this way, even a modest addition of antiplane shear can double the size of the Röthlisberger channels for a fixed water pressure or allow channels of a fixed radius to operate at lower effective pressure, potentially decreasing the strength of the surrounding bed. Furthermore, we show that Röthlisberger channels can be deformed away from a circular cross section under applied antiplane shear. These results can have broad impacts on sliding velocities and potentially affect the total ice flux out of glaciers and ice streams. Article in Journal/Newspaper Journal of Glaciology Cambridge University Press Journal of Glaciology 62 234 750 762 |
institution |
Open Polar |
collection |
Cambridge University Press |
op_collection_id |
crcambridgeupr |
language |
English |
description |
ABSTRACT Along the base of glaciers and ice sheets, the sliding of ice over till depends critically on water drainage. In locations where drainage occurs through Röthlisberger channels, the effective pressure along the base of the ice increases and can lead to a strengthening of the bed, which reduces glacier sliding. The formation of Röthlisberger channels depends on two competing effects: (1) melting from turbulent dissipation opens the channel walls and (2) creep flow driven by the weight of the overlying ice closes the channels radially inward. Variation in downstream ice velocity along the channel axis, referred to as an antiplane shear strain rate, decreases the effective viscosity. The softening of the ice increases creep closure velocities. In this way, even a modest addition of antiplane shear can double the size of the Röthlisberger channels for a fixed water pressure or allow channels of a fixed radius to operate at lower effective pressure, potentially decreasing the strength of the surrounding bed. Furthermore, we show that Röthlisberger channels can be deformed away from a circular cross section under applied antiplane shear. These results can have broad impacts on sliding velocities and potentially affect the total ice flux out of glaciers and ice streams. |
format |
Article in Journal/Newspaper |
author |
MEYER, COLIN R. FERNANDES, MATHEUS C. CREYTS, TIMOTHY T. RICE, JAMES R. |
spellingShingle |
MEYER, COLIN R. FERNANDES, MATHEUS C. CREYTS, TIMOTHY T. RICE, JAMES R. Effects of ice deformation on Röthlisberger channels and implications for transitions in subglacial hydrology |
author_facet |
MEYER, COLIN R. FERNANDES, MATHEUS C. CREYTS, TIMOTHY T. RICE, JAMES R. |
author_sort |
MEYER, COLIN R. |
title |
Effects of ice deformation on Röthlisberger channels and implications for transitions in subglacial hydrology |
title_short |
Effects of ice deformation on Röthlisberger channels and implications for transitions in subglacial hydrology |
title_full |
Effects of ice deformation on Röthlisberger channels and implications for transitions in subglacial hydrology |
title_fullStr |
Effects of ice deformation on Röthlisberger channels and implications for transitions in subglacial hydrology |
title_full_unstemmed |
Effects of ice deformation on Röthlisberger channels and implications for transitions in subglacial hydrology |
title_sort |
effects of ice deformation on röthlisberger channels and implications for transitions in subglacial hydrology |
publisher |
Cambridge University Press (CUP) |
publishDate |
2016 |
url |
http://dx.doi.org/10.1017/jog.2016.65 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143016000654 |
genre |
Journal of Glaciology |
genre_facet |
Journal of Glaciology |
op_source |
Journal of Glaciology volume 62, issue 234, page 750-762 ISSN 0022-1430 1727-5652 |
op_rights |
http://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1017/jog.2016.65 |
container_title |
Journal of Glaciology |
container_volume |
62 |
container_issue |
234 |
container_start_page |
750 |
op_container_end_page |
762 |
_version_ |
1810453547919081472 |