Seasonality of submesoscale flows in the ocean surface boundary layer
Seasonality of submesoscale flows in the ocean surface boundary layer
A signature of submesoscale flows in the upper ocean is skewness in the distribution of relative vorticity. Expected to result for high Rossby-number flows, such skewness has implications for mixing, dissipation and stratification within the upper ocean. An array of moorings deployed in the Northeast Atlantic for one year as part of the OSMOSIS experiment reveals that relative vorticity is positively skewed during winter even though the scale of the Rossby number is less than 0.5. Furthermore, this skewness is reduced to zero during spring and autumn. There is also evidence of modest seasonal variations in the gradient Rossby number. The proposed mechanism by which relative vorticity is skewed is that the ratio of lateral to vertical buoyancy gradients, as summarized by the inverse gradient Richardson number, restricts its range during winter but less so at other times of the year. These results support recent observations and model simulations suggesting the upper ocean is host to a seasonal cycle in submesoscale turbulence.
Diurnal, seasonal, and annual cycles, Eddies and mesoscale processes, General circulation, Turbulence, diffusion, and mixing processes, Upper ocean and mixed layer processes, submesoscale, instabilities, mixed layer, vorticity, turbulence
2118-2126
Buckingham, Christian E.
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Naveira Garabato, Alberto C.
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Thompson, Andrew F.
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Brannigan, Liam
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Lazar, Ayah
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Marshall, David P.
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Nurser, A.J. George
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Damerell, Gillian
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Heywood, Karen J.
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Belcher, Stephen E.
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16 March 2016
Buckingham, Christian E.
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Naveira Garabato, Alberto C.
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Thompson, Andrew F.
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Brannigan, Liam
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Lazar, Ayah
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Marshall, David P.
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Nurser, A.J. George
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Damerell, Gillian
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Heywood, Karen J.
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Belcher, Stephen E.
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Buckingham, Christian E., Naveira Garabato, Alberto C., Thompson, Andrew F., Brannigan, Liam, Lazar, Ayah, Marshall, David P., Nurser, A.J. George, Damerell, Gillian, Heywood, Karen J. and Belcher, Stephen E.
(2016)
Seasonality of submesoscale flows in the ocean surface boundary layer.
Geophysical Research Letters, 43 (5), .
(doi:10.1002/2016GL068009).
Abstract
A signature of submesoscale flows in the upper ocean is skewness in the distribution of relative vorticity. Expected to result for high Rossby-number flows, such skewness has implications for mixing, dissipation and stratification within the upper ocean. An array of moorings deployed in the Northeast Atlantic for one year as part of the OSMOSIS experiment reveals that relative vorticity is positively skewed during winter even though the scale of the Rossby number is less than 0.5. Furthermore, this skewness is reduced to zero during spring and autumn. There is also evidence of modest seasonal variations in the gradient Rossby number. The proposed mechanism by which relative vorticity is skewed is that the ratio of lateral to vertical buoyancy gradients, as summarized by the inverse gradient Richardson number, restricts its range during winter but less so at other times of the year. These results support recent observations and model simulations suggesting the upper ocean is host to a seasonal cycle in submesoscale turbulence.
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Accepted/In Press date: 20 February 2016
e-pub ahead of print date: 11 March 2016
Published date: 16 March 2016
Keywords:
Diurnal, seasonal, and annual cycles, Eddies and mesoscale processes, General circulation, Turbulence, diffusion, and mixing processes, Upper ocean and mixed layer processes, submesoscale, instabilities, mixed layer, vorticity, turbulence
Organisations:
Marine Systems Modelling, Physical Oceanography
Identifiers
Local EPrints ID: 388728
URI: http://eprints.soton.ac.uk/id/eprint/388728
ISSN: 0094-8276
PURE UUID: c7310cc0-9ea5-4d08-a599-ff656f463927
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Date deposited: 02 Mar 2016 10:34
Last modified: 15 Mar 2024 03:24
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Contributors
Author:
Christian E. Buckingham
Author:
Andrew F. Thompson
Author:
Liam Brannigan
Author:
Ayah Lazar
Author:
David P. Marshall
Author:
A.J. George Nurser
Author:
Gillian Damerell
Author:
Karen J. Heywood
Author:
Stephen E. Belcher
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