An annual cycle of submesoscale vertical flow and restratification in the upper ocean
Numerical simulations suggest that submesoscale turbulence may transform lateral buoyancy gradients into vertical stratification, and thus restratify the upper ocean via vertical flow. However, the observational evidence for this restratifying process has been lacking due to the difficulty in measur...
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ftsouthampton:oai:eprints.soton.ac.uk:430970 2023-07-30T04:05:47+02:00 An annual cycle of submesoscale vertical flow and restratification in the upper ocean Yu, Xiaolong Naveira Garabato, Alberto C. Martin, Adrian P. Buckingham, Christian E. Brannigan, Liam Su, Zhan 2019-06 text https://eprints.soton.ac.uk/430970/ https://eprints.soton.ac.uk/430970/1/jpo_d_18_0253.1.pdf en English eng https://eprints.soton.ac.uk/430970/1/jpo_d_18_0253.1.pdf Yu, Xiaolong, Naveira Garabato, Alberto C., Martin, Adrian P., Buckingham, Christian E., Brannigan, Liam and Su, Zhan (2019) An annual cycle of submesoscale vertical flow and restratification in the upper ocean. Journal of Physical Oceanography, 1439-1461. (doi:10.1175/JPO-D-18-0253.1 <http://dx.doi.org/10.1175/JPO-D-18-0253.1>). accepted_manuscript Article PeerReviewed 2019 ftsouthampton https://doi.org/10.1175/JPO-D-18-0253.1 2023-07-09T22:29:42Z Numerical simulations suggest that submesoscale turbulence may transform lateral buoyancy gradients into vertical stratification, and thus restratify the upper ocean via vertical flow. However, the observational evidence for this restratifying process has been lacking due to the difficulty in measuring such ephemeral phenomena, particularly over periods of months to years. This study presents an annual cycle of the vertical velocity and associated restratification estimated from two nested clusters of meso- and submesoscale-resolving moorings, deployed in a typical mid-ocean area of the Northeast Atlantic. Vertical velocities inferred using the non-diffusive density equation are substantially stronger at submesoscales (horizontal scales of 1-10 km) than at mesoscales (horizontal scales of 10-100 km), with respective root mean square values of 38.0 ± 6.9 m/day and 22.5 ± 3.3 m/day. The largest submesoscale vertical velocities and rates of restratification occur in events of a few days’ duration in winter and spring, and extend down to at least 200 m below the mixed layer base. These events commonly coincide with the enhancement of submesoscale lateral buoyancy gradients, which is itself associated with persistent mesoscale frontogenesis. This suggests that mesoscale frontogenesis is a regular precursor of the submesoscale turbulence that restratifies the upper ocean. The upper-ocean restratification induced by submesoscale motions integrated over the annual cycle is comparable in magnitude to the net destratification driven by local atmospheric cooling, indicating that submesoscale flows play a significant role in determining the climatological upper-ocean stratification in the study area. Article in Journal/Newspaper Northeast Atlantic University of Southampton: e-Prints Soton Journal of Physical Oceanography 49 6 1439 1461 |
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Open Polar |
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University of Southampton: e-Prints Soton |
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ftsouthampton |
language |
English |
description |
Numerical simulations suggest that submesoscale turbulence may transform lateral buoyancy gradients into vertical stratification, and thus restratify the upper ocean via vertical flow. However, the observational evidence for this restratifying process has been lacking due to the difficulty in measuring such ephemeral phenomena, particularly over periods of months to years. This study presents an annual cycle of the vertical velocity and associated restratification estimated from two nested clusters of meso- and submesoscale-resolving moorings, deployed in a typical mid-ocean area of the Northeast Atlantic. Vertical velocities inferred using the non-diffusive density equation are substantially stronger at submesoscales (horizontal scales of 1-10 km) than at mesoscales (horizontal scales of 10-100 km), with respective root mean square values of 38.0 ± 6.9 m/day and 22.5 ± 3.3 m/day. The largest submesoscale vertical velocities and rates of restratification occur in events of a few days’ duration in winter and spring, and extend down to at least 200 m below the mixed layer base. These events commonly coincide with the enhancement of submesoscale lateral buoyancy gradients, which is itself associated with persistent mesoscale frontogenesis. This suggests that mesoscale frontogenesis is a regular precursor of the submesoscale turbulence that restratifies the upper ocean. The upper-ocean restratification induced by submesoscale motions integrated over the annual cycle is comparable in magnitude to the net destratification driven by local atmospheric cooling, indicating that submesoscale flows play a significant role in determining the climatological upper-ocean stratification in the study area. |
format |
Article in Journal/Newspaper |
author |
Yu, Xiaolong Naveira Garabato, Alberto C. Martin, Adrian P. Buckingham, Christian E. Brannigan, Liam Su, Zhan |
spellingShingle |
Yu, Xiaolong Naveira Garabato, Alberto C. Martin, Adrian P. Buckingham, Christian E. Brannigan, Liam Su, Zhan An annual cycle of submesoscale vertical flow and restratification in the upper ocean |
author_facet |
Yu, Xiaolong Naveira Garabato, Alberto C. Martin, Adrian P. Buckingham, Christian E. Brannigan, Liam Su, Zhan |
author_sort |
Yu, Xiaolong |
title |
An annual cycle of submesoscale vertical flow and restratification in the upper ocean |
title_short |
An annual cycle of submesoscale vertical flow and restratification in the upper ocean |
title_full |
An annual cycle of submesoscale vertical flow and restratification in the upper ocean |
title_fullStr |
An annual cycle of submesoscale vertical flow and restratification in the upper ocean |
title_full_unstemmed |
An annual cycle of submesoscale vertical flow and restratification in the upper ocean |
title_sort |
annual cycle of submesoscale vertical flow and restratification in the upper ocean |
publishDate |
2019 |
url |
https://eprints.soton.ac.uk/430970/ https://eprints.soton.ac.uk/430970/1/jpo_d_18_0253.1.pdf |
genre |
Northeast Atlantic |
genre_facet |
Northeast Atlantic |
op_relation |
https://eprints.soton.ac.uk/430970/1/jpo_d_18_0253.1.pdf Yu, Xiaolong, Naveira Garabato, Alberto C., Martin, Adrian P., Buckingham, Christian E., Brannigan, Liam and Su, Zhan (2019) An annual cycle of submesoscale vertical flow and restratification in the upper ocean. Journal of Physical Oceanography, 1439-1461. (doi:10.1175/JPO-D-18-0253.1 <http://dx.doi.org/10.1175/JPO-D-18-0253.1>). |
op_rights |
accepted_manuscript |
op_doi |
https://doi.org/10.1175/JPO-D-18-0253.1 |
container_title |
Journal of Physical Oceanography |
container_volume |
49 |
container_issue |
6 |
container_start_page |
1439 |
op_container_end_page |
1461 |
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1772817929806544896 |