Sea ice thickness from air-coupled flexural waves
Air-coupled flexural waves (ACFWs) appear as wave trains of constant frequency that arrive in advance of the direct air wave from an impulsive source travelling over a floating ice sheet. The frequency of these waves varies with the flexural stiffness of the ice sheet, which is controlled by a combi...
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Copernicus Publications
2021
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Online Access: | https://doi.org/10.5194/tc-15-2939-2021 https://tc.copernicus.org/articles/15/2939/2021/tc-15-2939-2021.pdf https://doaj.org/article/babd0d6aa6394d999c023377d9768366 |
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fttriple:oai:gotriple.eu:oai:doaj.org/article:babd0d6aa6394d999c023377d9768366 2023-05-15T16:40:30+02:00 Sea ice thickness from air-coupled flexural waves R. Romeyn A. Hanssen B. O. Ruud T. A. Johansen 2021-06-01 https://doi.org/10.5194/tc-15-2939-2021 https://tc.copernicus.org/articles/15/2939/2021/tc-15-2939-2021.pdf https://doaj.org/article/babd0d6aa6394d999c023377d9768366 en eng Copernicus Publications doi:10.5194/tc-15-2939-2021 1994-0416 1994-0424 https://tc.copernicus.org/articles/15/2939/2021/tc-15-2939-2021.pdf https://doaj.org/article/babd0d6aa6394d999c023377d9768366 undefined The Cryosphere, Vol 15, Pp 2939-2955 (2021) envir geo Journal Article https://vocabularies.coar-repositories.org/resource_types/c_6501/ 2021 fttriple https://doi.org/10.5194/tc-15-2939-2021 2023-01-22T19:22:57Z Air-coupled flexural waves (ACFWs) appear as wave trains of constant frequency that arrive in advance of the direct air wave from an impulsive source travelling over a floating ice sheet. The frequency of these waves varies with the flexural stiffness of the ice sheet, which is controlled by a combination of thickness and elastic properties. We develop a theoretical framework to understand these waves, utilizing modern numerical and Fourier methods to give a simpler and more accessible description than the pioneering yet unwieldy analytical efforts of the 1950s. Our favoured dynamical model can be understood in terms of linear filter theory and is closely related to models used to describe the flexural waves produced by moving vehicles on floating plates. We find that air-coupled flexural waves are a real and measurable component of the total wave field of floating ice sheets excited by impulsive sources, and we present a simple closed-form estimator for the ice thickness based on observable properties of the air-coupled flexural waves. Our study is focused on first-year sea ice of ∼ 20–80 cm thickness in Van Mijenfjorden, Svalbard, that was investigated through active source seismic experiments over four field campaigns in 2013, 2016, 2017 and 2018. The air-coupled flexural wave for the sea ice system considered in this study occurs at a constant frequency thickness product of ∼ 48 Hz m. Our field data include ice ranging from ∼ 20–80 cm thickness with corresponding air-coupled flexural frequencies from 240 Hz for the thinnest ice to 60 Hz for the thickest ice. While air-coupled flexural waves for thick sea ice have received little attention, the readily audible, higher frequencies associated with thin ice on freshwater lakes and rivers are well known to the ice-skating community and have been reported in popular media. The results of this study and further examples from lake ice suggest the possibility of non-contact estimation of ice thickness using simple, inexpensive microphones located above the ice sheet ... Article in Journal/Newspaper Ice Sheet Sea ice Svalbard The Cryosphere Van Mijenfjorden Unknown Svalbard Van Mijenfjorden ENVELOPE(14.667,14.667,77.717,77.717) The Cryosphere 15 6 2939 2955 |
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envir geo |
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envir geo R. Romeyn A. Hanssen B. O. Ruud T. A. Johansen Sea ice thickness from air-coupled flexural waves |
topic_facet |
envir geo |
description |
Air-coupled flexural waves (ACFWs) appear as wave trains of constant frequency that arrive in advance of the direct air wave from an impulsive source travelling over a floating ice sheet. The frequency of these waves varies with the flexural stiffness of the ice sheet, which is controlled by a combination of thickness and elastic properties. We develop a theoretical framework to understand these waves, utilizing modern numerical and Fourier methods to give a simpler and more accessible description than the pioneering yet unwieldy analytical efforts of the 1950s. Our favoured dynamical model can be understood in terms of linear filter theory and is closely related to models used to describe the flexural waves produced by moving vehicles on floating plates. We find that air-coupled flexural waves are a real and measurable component of the total wave field of floating ice sheets excited by impulsive sources, and we present a simple closed-form estimator for the ice thickness based on observable properties of the air-coupled flexural waves. Our study is focused on first-year sea ice of ∼ 20–80 cm thickness in Van Mijenfjorden, Svalbard, that was investigated through active source seismic experiments over four field campaigns in 2013, 2016, 2017 and 2018. The air-coupled flexural wave for the sea ice system considered in this study occurs at a constant frequency thickness product of ∼ 48 Hz m. Our field data include ice ranging from ∼ 20–80 cm thickness with corresponding air-coupled flexural frequencies from 240 Hz for the thinnest ice to 60 Hz for the thickest ice. While air-coupled flexural waves for thick sea ice have received little attention, the readily audible, higher frequencies associated with thin ice on freshwater lakes and rivers are well known to the ice-skating community and have been reported in popular media. The results of this study and further examples from lake ice suggest the possibility of non-contact estimation of ice thickness using simple, inexpensive microphones located above the ice sheet ... |
format |
Article in Journal/Newspaper |
author |
R. Romeyn A. Hanssen B. O. Ruud T. A. Johansen |
author_facet |
R. Romeyn A. Hanssen B. O. Ruud T. A. Johansen |
author_sort |
R. Romeyn |
title |
Sea ice thickness from air-coupled flexural waves |
title_short |
Sea ice thickness from air-coupled flexural waves |
title_full |
Sea ice thickness from air-coupled flexural waves |
title_fullStr |
Sea ice thickness from air-coupled flexural waves |
title_full_unstemmed |
Sea ice thickness from air-coupled flexural waves |
title_sort |
sea ice thickness from air-coupled flexural waves |
publisher |
Copernicus Publications |
publishDate |
2021 |
url |
https://doi.org/10.5194/tc-15-2939-2021 https://tc.copernicus.org/articles/15/2939/2021/tc-15-2939-2021.pdf https://doaj.org/article/babd0d6aa6394d999c023377d9768366 |
long_lat |
ENVELOPE(14.667,14.667,77.717,77.717) |
geographic |
Svalbard Van Mijenfjorden |
geographic_facet |
Svalbard Van Mijenfjorden |
genre |
Ice Sheet Sea ice Svalbard The Cryosphere Van Mijenfjorden |
genre_facet |
Ice Sheet Sea ice Svalbard The Cryosphere Van Mijenfjorden |
op_source |
The Cryosphere, Vol 15, Pp 2939-2955 (2021) |
op_relation |
doi:10.5194/tc-15-2939-2021 1994-0416 1994-0424 https://tc.copernicus.org/articles/15/2939/2021/tc-15-2939-2021.pdf https://doaj.org/article/babd0d6aa6394d999c023377d9768366 |
op_rights |
undefined |
op_doi |
https://doi.org/10.5194/tc-15-2939-2021 |
container_title |
The Cryosphere |
container_volume |
15 |
container_issue |
6 |
container_start_page |
2939 |
op_container_end_page |
2955 |
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1766030896289284096 |