Cyclic steps on ice
Boundary waves often form at the interface between ice and fluid flowing adjacent to it, such as ripples under river ice covers, and steps on the bed of supraglacial meltwater channels. They may also be formed by wind, such as the megadunes on the Antarctic ice sheet. Spiral troughs on the polar ice...
Published in: | Journal of Geophysical Research: Earth Surface |
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Online Access: | http://hdl.handle.net/2115/64599 https://doi.org/10.1002/2015JF003736 |
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fthokunivhus:oai:eprints.lib.hokudai.ac.jp:2115/64599 2023-05-15T13:40:56+02:00 Cyclic steps on ice Yokokawa, M. Izumi, N. Naito, K. Parker, G. Yamada, T. Greve, R. http://hdl.handle.net/2115/64599 https://doi.org/10.1002/2015JF003736 eng eng American Geophysical Union (AGU) http://hdl.handle.net/2115/64599 Journal of Geophysical Research: Earth Surface, 121(5): 1023-1048 http://dx.doi.org/10.1002/2015JF003736 Copyright 2016 American Geophysical Union. All Rights Reserved. article fthokunivhus https://doi.org/10.1002/2015JF003736 2022-11-18T01:04:10Z Boundary waves often form at the interface between ice and fluid flowing adjacent to it, such as ripples under river ice covers, and steps on the bed of supraglacial meltwater channels. They may also be formed by wind, such as the megadunes on the Antarctic ice sheet. Spiral troughs on the polar ice caps of Mars have been interpreted to be cyclic steps formed by katabatic wind blowing over ice. Cyclic steps are relatives of upstream-migrating antidunes. Cyclic step formation on ice is not only a mechanical but also a thermodynamic process. There have been very few studies on the formation of either cyclic steps or upstream-migrating antidunes on ice. In this study, we performed flume experiments to reproduce cyclic steps on ice by flowing water, and found that trains of steps form when the Froude number is larger than unity. The features of those steps allow them to be identified as ice-bed analogs of cyclic steps in alluvial and bedrock rivers. We performed a linear stability analysis and obtained a physical explanation of the formation of upstream-migrating antidunes, i.e., precursors of cyclic steps. We compared the results of experiments with the predictions of the analysis and found the observed steps fall in the range where the analysis predicts interfacial instability. We also found that short antidune-like undulations formed as a precursor to the appearance of well-defined steps. This fact suggests that such antidune-like undulations correspond to the instability predicted by the analysis and are precursors of cyclic steps. Article in Journal/Newspaper Antarc* Antarctic Ice Sheet Hokkaido University Collection of Scholarly and Academic Papers (HUSCAP) Antarctic The Antarctic Journal of Geophysical Research: Earth Surface 121 5 1023 1048 |
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Open Polar |
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Hokkaido University Collection of Scholarly and Academic Papers (HUSCAP) |
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fthokunivhus |
language |
English |
description |
Boundary waves often form at the interface between ice and fluid flowing adjacent to it, such as ripples under river ice covers, and steps on the bed of supraglacial meltwater channels. They may also be formed by wind, such as the megadunes on the Antarctic ice sheet. Spiral troughs on the polar ice caps of Mars have been interpreted to be cyclic steps formed by katabatic wind blowing over ice. Cyclic steps are relatives of upstream-migrating antidunes. Cyclic step formation on ice is not only a mechanical but also a thermodynamic process. There have been very few studies on the formation of either cyclic steps or upstream-migrating antidunes on ice. In this study, we performed flume experiments to reproduce cyclic steps on ice by flowing water, and found that trains of steps form when the Froude number is larger than unity. The features of those steps allow them to be identified as ice-bed analogs of cyclic steps in alluvial and bedrock rivers. We performed a linear stability analysis and obtained a physical explanation of the formation of upstream-migrating antidunes, i.e., precursors of cyclic steps. We compared the results of experiments with the predictions of the analysis and found the observed steps fall in the range where the analysis predicts interfacial instability. We also found that short antidune-like undulations formed as a precursor to the appearance of well-defined steps. This fact suggests that such antidune-like undulations correspond to the instability predicted by the analysis and are precursors of cyclic steps. |
format |
Article in Journal/Newspaper |
author |
Yokokawa, M. Izumi, N. Naito, K. Parker, G. Yamada, T. Greve, R. |
spellingShingle |
Yokokawa, M. Izumi, N. Naito, K. Parker, G. Yamada, T. Greve, R. Cyclic steps on ice |
author_facet |
Yokokawa, M. Izumi, N. Naito, K. Parker, G. Yamada, T. Greve, R. |
author_sort |
Yokokawa, M. |
title |
Cyclic steps on ice |
title_short |
Cyclic steps on ice |
title_full |
Cyclic steps on ice |
title_fullStr |
Cyclic steps on ice |
title_full_unstemmed |
Cyclic steps on ice |
title_sort |
cyclic steps on ice |
publisher |
American Geophysical Union (AGU) |
url |
http://hdl.handle.net/2115/64599 https://doi.org/10.1002/2015JF003736 |
geographic |
Antarctic The Antarctic |
geographic_facet |
Antarctic The Antarctic |
genre |
Antarc* Antarctic Ice Sheet |
genre_facet |
Antarc* Antarctic Ice Sheet |
op_relation |
http://hdl.handle.net/2115/64599 Journal of Geophysical Research: Earth Surface, 121(5): 1023-1048 http://dx.doi.org/10.1002/2015JF003736 |
op_rights |
Copyright 2016 American Geophysical Union. All Rights Reserved. |
op_doi |
https://doi.org/10.1002/2015JF003736 |
container_title |
Journal of Geophysical Research: Earth Surface |
container_volume |
121 |
container_issue |
5 |
container_start_page |
1023 |
op_container_end_page |
1048 |
_version_ |
1766143501246922752 |