Observed eddy-internal wave interactions in the Southern Ocean
The physical mechanisms that remove energy from the Southern Ocean’s vigorous mesoscale eddy field are not well understood. One proposed mechanism is direct energy transfer to the internal wave field in the ocean interior, via eddy-induced straining and shearing of preexisting internal waves. The ma...
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ftsouthampton:oai:eprints.soton.ac.uk:445030 2023-08-27T04:11:52+02:00 Observed eddy-internal wave interactions in the Southern Ocean Cusack, Jesse M. Brearley, J. Alexander Naveira Garabato, Alberto C. Smeed, David A. Polzin, Kurt L. Velzeboer, Nick Shakespeare, Callum J. 2020-10-15 text https://eprints.soton.ac.uk/445030/ https://eprints.soton.ac.uk/445030/1/jpod200001.pdf en English eng https://eprints.soton.ac.uk/445030/1/jpod200001.pdf Cusack, Jesse M., Brearley, J. Alexander, Naveira Garabato, Alberto C., Smeed, David A., Polzin, Kurt L., Velzeboer, Nick and Shakespeare, Callum J. (2020) Observed eddy-internal wave interactions in the Southern Ocean. Journal of Physical Oceanography, 50 (10), 3043-3062. (doi:10.1175/JPO-D-20-0001.1 <http://dx.doi.org/10.1175/JPO-D-20-0001.1>). cc_by_4 Article PeerReviewed 2020 ftsouthampton https://doi.org/10.1175/JPO-D-20-0001.1 2023-08-03T22:24:55Z The physical mechanisms that remove energy from the Southern Ocean’s vigorous mesoscale eddy field are not well understood. One proposed mechanism is direct energy transfer to the internal wave field in the ocean interior, via eddy-induced straining and shearing of preexisting internal waves. The magnitude, vertical structure, and temporal variability of the rate of energy transfer between eddies and internal waves is quantified from a 14-month deployment of a mooring cluster in the Scotia Sea. Velocity and buoyancy observations are decomposed into wave and eddy components, and the energy transfer is estimated using the Reynolds-averaged energy equation. We find that eddies gain energy from the internal wave field at a rate of −2.2 ± 0.6 mW m−2, integrated from the bottom to 566 m below the surface. This result can be decomposed into a positive (eddy to wave) component, equal to 0.2 ± 0.1 mW m−2, driven by horizontal straining of internal waves, and a negative (wave to eddy) component, equal to −2.5 ± 0.6 mW m−2, driven by vertical shearing of the wave spectrum. Temporal variability of the transfer rate is much greater than the mean value. Close to topography, large energy transfers are associated with low-frequency buoyancy fluxes, the underpinning physics of which do not conform to linear wave dynamics and are thereby in need of further research. Our work suggests that eddy–internal wave interactions may play a significant role in the energy balance of the Southern Ocean mesoscale eddy and internal wave fields. Article in Journal/Newspaper Scotia Sea Southern Ocean University of Southampton: e-Prints Soton Scotia Sea Southern Ocean Journal of Physical Oceanography 50 10 3043 3062 |
institution |
Open Polar |
collection |
University of Southampton: e-Prints Soton |
op_collection_id |
ftsouthampton |
language |
English |
description |
The physical mechanisms that remove energy from the Southern Ocean’s vigorous mesoscale eddy field are not well understood. One proposed mechanism is direct energy transfer to the internal wave field in the ocean interior, via eddy-induced straining and shearing of preexisting internal waves. The magnitude, vertical structure, and temporal variability of the rate of energy transfer between eddies and internal waves is quantified from a 14-month deployment of a mooring cluster in the Scotia Sea. Velocity and buoyancy observations are decomposed into wave and eddy components, and the energy transfer is estimated using the Reynolds-averaged energy equation. We find that eddies gain energy from the internal wave field at a rate of −2.2 ± 0.6 mW m−2, integrated from the bottom to 566 m below the surface. This result can be decomposed into a positive (eddy to wave) component, equal to 0.2 ± 0.1 mW m−2, driven by horizontal straining of internal waves, and a negative (wave to eddy) component, equal to −2.5 ± 0.6 mW m−2, driven by vertical shearing of the wave spectrum. Temporal variability of the transfer rate is much greater than the mean value. Close to topography, large energy transfers are associated with low-frequency buoyancy fluxes, the underpinning physics of which do not conform to linear wave dynamics and are thereby in need of further research. Our work suggests that eddy–internal wave interactions may play a significant role in the energy balance of the Southern Ocean mesoscale eddy and internal wave fields. |
format |
Article in Journal/Newspaper |
author |
Cusack, Jesse M. Brearley, J. Alexander Naveira Garabato, Alberto C. Smeed, David A. Polzin, Kurt L. Velzeboer, Nick Shakespeare, Callum J. |
spellingShingle |
Cusack, Jesse M. Brearley, J. Alexander Naveira Garabato, Alberto C. Smeed, David A. Polzin, Kurt L. Velzeboer, Nick Shakespeare, Callum J. Observed eddy-internal wave interactions in the Southern Ocean |
author_facet |
Cusack, Jesse M. Brearley, J. Alexander Naveira Garabato, Alberto C. Smeed, David A. Polzin, Kurt L. Velzeboer, Nick Shakespeare, Callum J. |
author_sort |
Cusack, Jesse M. |
title |
Observed eddy-internal wave interactions in the Southern Ocean |
title_short |
Observed eddy-internal wave interactions in the Southern Ocean |
title_full |
Observed eddy-internal wave interactions in the Southern Ocean |
title_fullStr |
Observed eddy-internal wave interactions in the Southern Ocean |
title_full_unstemmed |
Observed eddy-internal wave interactions in the Southern Ocean |
title_sort |
observed eddy-internal wave interactions in the southern ocean |
publishDate |
2020 |
url |
https://eprints.soton.ac.uk/445030/ https://eprints.soton.ac.uk/445030/1/jpod200001.pdf |
geographic |
Scotia Sea Southern Ocean |
geographic_facet |
Scotia Sea Southern Ocean |
genre |
Scotia Sea Southern Ocean |
genre_facet |
Scotia Sea Southern Ocean |
op_relation |
https://eprints.soton.ac.uk/445030/1/jpod200001.pdf Cusack, Jesse M., Brearley, J. Alexander, Naveira Garabato, Alberto C., Smeed, David A., Polzin, Kurt L., Velzeboer, Nick and Shakespeare, Callum J. (2020) Observed eddy-internal wave interactions in the Southern Ocean. Journal of Physical Oceanography, 50 (10), 3043-3062. (doi:10.1175/JPO-D-20-0001.1 <http://dx.doi.org/10.1175/JPO-D-20-0001.1>). |
op_rights |
cc_by_4 |
op_doi |
https://doi.org/10.1175/JPO-D-20-0001.1 |
container_title |
Journal of Physical Oceanography |
container_volume |
50 |
container_issue |
10 |
container_start_page |
3043 |
op_container_end_page |
3062 |
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1775355484446916608 |