On the propagation of acoustic–gravity waves under elastic ice sheets
The propagation of wave disturbances in water of varying depth bounded above by ice sheets is discussed, accounting for gravity, compressibility and elasticity effects. Considering the more realistic scenario of elastic ice sheets reveals a continuous spectrum of acoustic–gravity modes that propagat...
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Language: | English |
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Cambridge University Press (CUP)
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crcambridgeupr:10.1017/jfm.2017.808 2024-09-15T18:12:18+00:00 On the propagation of acoustic–gravity waves under elastic ice sheets Abdolali, Ali Kadri, Usama Parsons, Wade Kirby, James T. 2018 http://dx.doi.org/10.1017/jfm.2017.808 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022112017008084 en eng Cambridge University Press (CUP) https://www.cambridge.org/core/terms Journal of Fluid Mechanics volume 837, page 640-656 ISSN 0022-1120 1469-7645 journal-article 2018 crcambridgeupr https://doi.org/10.1017/jfm.2017.808 2024-08-07T04:01:36Z The propagation of wave disturbances in water of varying depth bounded above by ice sheets is discussed, accounting for gravity, compressibility and elasticity effects. Considering the more realistic scenario of elastic ice sheets reveals a continuous spectrum of acoustic–gravity modes that propagate even below the cutoff frequency of the rigid surface solution where surface (gravity) waves cannot exist. The balance between gravitational forces and oscillations in the ice sheet defines a new dimensionless quantity $\mathfrak{Ka}$ . When the ice sheet is relatively thin and the prescribed frequency is relatively low ( $\mathfrak{Ka}\ll 1$ ), the free-surface bottom-pressure solution is retrieved in full. However, thicker ice sheets or propagation of relatively higher frequency modes ( $\mathfrak{Ka}\gg 1$ ) alter the solution fundamentally, which is reflected in an amplified asymmetric signature and different characteristics of the eigenvalues, such that the bottom pressure is amplified when acoustic–gravity waves are transmitted to shallower waters. To analyse these scenarios, an analytical solution and a depth-integrated equation are derived for the cases of constant and varying depths, respectively. Together, these are capable of modelling realistic ocean geometries and an inhomogeneous distribution of ice sheets. Article in Journal/Newspaper Ice Sheet Cambridge University Press Journal of Fluid Mechanics 837 640 656 |
institution |
Open Polar |
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Cambridge University Press |
op_collection_id |
crcambridgeupr |
language |
English |
description |
The propagation of wave disturbances in water of varying depth bounded above by ice sheets is discussed, accounting for gravity, compressibility and elasticity effects. Considering the more realistic scenario of elastic ice sheets reveals a continuous spectrum of acoustic–gravity modes that propagate even below the cutoff frequency of the rigid surface solution where surface (gravity) waves cannot exist. The balance between gravitational forces and oscillations in the ice sheet defines a new dimensionless quantity $\mathfrak{Ka}$ . When the ice sheet is relatively thin and the prescribed frequency is relatively low ( $\mathfrak{Ka}\ll 1$ ), the free-surface bottom-pressure solution is retrieved in full. However, thicker ice sheets or propagation of relatively higher frequency modes ( $\mathfrak{Ka}\gg 1$ ) alter the solution fundamentally, which is reflected in an amplified asymmetric signature and different characteristics of the eigenvalues, such that the bottom pressure is amplified when acoustic–gravity waves are transmitted to shallower waters. To analyse these scenarios, an analytical solution and a depth-integrated equation are derived for the cases of constant and varying depths, respectively. Together, these are capable of modelling realistic ocean geometries and an inhomogeneous distribution of ice sheets. |
format |
Article in Journal/Newspaper |
author |
Abdolali, Ali Kadri, Usama Parsons, Wade Kirby, James T. |
spellingShingle |
Abdolali, Ali Kadri, Usama Parsons, Wade Kirby, James T. On the propagation of acoustic–gravity waves under elastic ice sheets |
author_facet |
Abdolali, Ali Kadri, Usama Parsons, Wade Kirby, James T. |
author_sort |
Abdolali, Ali |
title |
On the propagation of acoustic–gravity waves under elastic ice sheets |
title_short |
On the propagation of acoustic–gravity waves under elastic ice sheets |
title_full |
On the propagation of acoustic–gravity waves under elastic ice sheets |
title_fullStr |
On the propagation of acoustic–gravity waves under elastic ice sheets |
title_full_unstemmed |
On the propagation of acoustic–gravity waves under elastic ice sheets |
title_sort |
on the propagation of acoustic–gravity waves under elastic ice sheets |
publisher |
Cambridge University Press (CUP) |
publishDate |
2018 |
url |
http://dx.doi.org/10.1017/jfm.2017.808 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022112017008084 |
genre |
Ice Sheet |
genre_facet |
Ice Sheet |
op_source |
Journal of Fluid Mechanics volume 837, page 640-656 ISSN 0022-1120 1469-7645 |
op_rights |
https://www.cambridge.org/core/terms |
op_doi |
https://doi.org/10.1017/jfm.2017.808 |
container_title |
Journal of Fluid Mechanics |
container_volume |
837 |
container_start_page |
640 |
op_container_end_page |
656 |
_version_ |
1810449884848848896 |