Variations in hydraulic efficiency of the subglacial drainage landsystem control surging and streaming regimes of outlet glaciers
Abstract Surging and streaming of glaciers are modulated by meltwater availability and pressure which controls mechanical coupling at their beds. Using laboratory-scale experimental modelling and palaeoglaciological mapping, we explore how subglacial drainage landsystems control meltwater drainage e...
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Online Access: | http://dx.doi.org/10.1017/jog.2022.107 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143022001071 |
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crcambridgeupr:10.1017/jog.2022.107 2024-04-28T08:26:45+00:00 Variations in hydraulic efficiency of the subglacial drainage landsystem control surging and streaming regimes of outlet glaciers Ravier, Édouard Lelandais, Thomas Vérité, Jean Bourgeois, Olivier Agence Nationale de la Recherche 2022 http://dx.doi.org/10.1017/jog.2022.107 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143022001071 en eng Cambridge University Press (CUP) http://creativecommons.org/licenses/by/4.0/ Journal of Glaciology volume 69, issue 276, page 860-878 ISSN 0022-1430 1727-5652 Earth-Surface Processes journal-article 2022 crcambridgeupr https://doi.org/10.1017/jog.2022.107 2024-04-09T06:55:44Z Abstract Surging and streaming of glaciers are modulated by meltwater availability and pressure which controls mechanical coupling at their beds. Using laboratory-scale experimental modelling and palaeoglaciological mapping, we explore how subglacial drainage landsystems control meltwater drainage efficiency and ice flow velocities for terrestrial-based ice lobes resting on flat horizontal and permeable beds. Two end-members regimes, surging and streaming, appear in our experiments. The surge regime is characterised by a rapid increase of drainage efficiency through development of tunnel valleys and their tributaries, thus reducing the duration of ice flow speed-up events by lowering water pressures and increasing ice-bed coupling. Tunnel valleys connected to ice lobe margins, submarginal thrust moraines, reduced ice lobe extensions and ephemeral shear margins are the most distinctive characteristics of this regime. The stream regime is characterised by disconnected channels of smaller dimensions unable to evacuate all the meltwater: this prolonged drainage inefficiency leads to sustained high ice flow velocity and steady shear margins. Small and rectilinear meltwater channels devoid of tributaries, often disconnected from ice lobe margins, and lineation swarms are diagnostic of this regime. Article in Journal/Newspaper Journal of Glaciology Cambridge University Press Journal of Glaciology 1 19 |
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Open Polar |
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Cambridge University Press |
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crcambridgeupr |
language |
English |
topic |
Earth-Surface Processes |
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Earth-Surface Processes Ravier, Édouard Lelandais, Thomas Vérité, Jean Bourgeois, Olivier Variations in hydraulic efficiency of the subglacial drainage landsystem control surging and streaming regimes of outlet glaciers |
topic_facet |
Earth-Surface Processes |
description |
Abstract Surging and streaming of glaciers are modulated by meltwater availability and pressure which controls mechanical coupling at their beds. Using laboratory-scale experimental modelling and palaeoglaciological mapping, we explore how subglacial drainage landsystems control meltwater drainage efficiency and ice flow velocities for terrestrial-based ice lobes resting on flat horizontal and permeable beds. Two end-members regimes, surging and streaming, appear in our experiments. The surge regime is characterised by a rapid increase of drainage efficiency through development of tunnel valleys and their tributaries, thus reducing the duration of ice flow speed-up events by lowering water pressures and increasing ice-bed coupling. Tunnel valleys connected to ice lobe margins, submarginal thrust moraines, reduced ice lobe extensions and ephemeral shear margins are the most distinctive characteristics of this regime. The stream regime is characterised by disconnected channels of smaller dimensions unable to evacuate all the meltwater: this prolonged drainage inefficiency leads to sustained high ice flow velocity and steady shear margins. Small and rectilinear meltwater channels devoid of tributaries, often disconnected from ice lobe margins, and lineation swarms are diagnostic of this regime. |
author2 |
Agence Nationale de la Recherche |
format |
Article in Journal/Newspaper |
author |
Ravier, Édouard Lelandais, Thomas Vérité, Jean Bourgeois, Olivier |
author_facet |
Ravier, Édouard Lelandais, Thomas Vérité, Jean Bourgeois, Olivier |
author_sort |
Ravier, Édouard |
title |
Variations in hydraulic efficiency of the subglacial drainage landsystem control surging and streaming regimes of outlet glaciers |
title_short |
Variations in hydraulic efficiency of the subglacial drainage landsystem control surging and streaming regimes of outlet glaciers |
title_full |
Variations in hydraulic efficiency of the subglacial drainage landsystem control surging and streaming regimes of outlet glaciers |
title_fullStr |
Variations in hydraulic efficiency of the subglacial drainage landsystem control surging and streaming regimes of outlet glaciers |
title_full_unstemmed |
Variations in hydraulic efficiency of the subglacial drainage landsystem control surging and streaming regimes of outlet glaciers |
title_sort |
variations in hydraulic efficiency of the subglacial drainage landsystem control surging and streaming regimes of outlet glaciers |
publisher |
Cambridge University Press (CUP) |
publishDate |
2022 |
url |
http://dx.doi.org/10.1017/jog.2022.107 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143022001071 |
genre |
Journal of Glaciology |
genre_facet |
Journal of Glaciology |
op_source |
Journal of Glaciology volume 69, issue 276, page 860-878 ISSN 0022-1430 1727-5652 |
op_rights |
http://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1017/jog.2022.107 |
container_title |
Journal of Glaciology |
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1 |
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19 |
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1797586008759336960 |