Towards a mesoscale eddy closure
Zusammenfassung A turbulence closure for the effect of mesoscale eddies in non-eddy-resolving ocean models is proposed. The closure consists of a prognostic equation for the eddy kinetic energy (EKE) that is integrated as an additional model equation, and a diagnostic relation for an eddy length sca...
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Online Access: | https://oceanrep.geomar.de/id/eprint/2504/ https://oceanrep.geomar.de/id/eprint/2504/1/Eden.pdf https://doi.org/10.1016/j.ocemod.2007.09.002 |
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ftoceanrep:oai:oceanrep.geomar.de:2504 2023-05-15T17:30:52+02:00 Towards a mesoscale eddy closure Eden, Carsten Greatbatch, Richard 2008 text https://oceanrep.geomar.de/id/eprint/2504/ https://oceanrep.geomar.de/id/eprint/2504/1/Eden.pdf https://doi.org/10.1016/j.ocemod.2007.09.002 en eng Elsevier https://oceanrep.geomar.de/id/eprint/2504/1/Eden.pdf Eden, C. and Greatbatch, R. (2008) Towards a mesoscale eddy closure. Ocean Modelling, 20 (3). pp. 223-239. DOI 10.1016/j.ocemod.2007.09.002 <https://doi.org/10.1016/j.ocemod.2007.09.002>. doi:10.1016/j.ocemod.2007.09.002 info:eu-repo/semantics/restrictedAccess Article PeerReviewed 2008 ftoceanrep https://doi.org/10.1016/j.ocemod.2007.09.002 2023-04-07T14:46:00Z Zusammenfassung A turbulence closure for the effect of mesoscale eddies in non-eddy-resolving ocean models is proposed. The closure consists of a prognostic equation for the eddy kinetic energy (EKE) that is integrated as an additional model equation, and a diagnostic relation for an eddy length scale (L), which is given by the minimum of Rhines scale and Rossby radius. Combining EKE and L using a standard mixing length assumption gives a diffusivity (K), corresponding to the thickness diffusivity in the [Gent, P.R., McWilliams, J.C. 1990. Isopycnal mixing in ocean circulation models. J. Phys. Oceanogr. 20, 150-155] parameterisation. Assuming downgradient mixing of potential vorticity with identical diffusivity shows how K is related to horizontal and vertical mixing processes in the horizontal momentum equation, and also enables us to parameterise the source of EKE related to eddy momentum fluxes. The mesoscale eddy closure is evaluated using synthetic data from two different eddy-resolving models covering the North Atlantic Ocean and the Southern Ocean, respectively. The diagnosis shows that the mixing length assumption together with the definition of eddy length scales is valid within certain limitations. Furthermore, implementation of the closure in non-eddy-resolving models of the North Atlantic and the Southern Ocean shows consistently that the closure has skill at reproducing the results of the eddy-resolving model versions in terms of EKE and K. Article in Journal/Newspaper North Atlantic Southern Ocean OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) Southern Ocean Ocean Modelling 20 3 223 239 |
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OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
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ftoceanrep |
language |
English |
description |
Zusammenfassung A turbulence closure for the effect of mesoscale eddies in non-eddy-resolving ocean models is proposed. The closure consists of a prognostic equation for the eddy kinetic energy (EKE) that is integrated as an additional model equation, and a diagnostic relation for an eddy length scale (L), which is given by the minimum of Rhines scale and Rossby radius. Combining EKE and L using a standard mixing length assumption gives a diffusivity (K), corresponding to the thickness diffusivity in the [Gent, P.R., McWilliams, J.C. 1990. Isopycnal mixing in ocean circulation models. J. Phys. Oceanogr. 20, 150-155] parameterisation. Assuming downgradient mixing of potential vorticity with identical diffusivity shows how K is related to horizontal and vertical mixing processes in the horizontal momentum equation, and also enables us to parameterise the source of EKE related to eddy momentum fluxes. The mesoscale eddy closure is evaluated using synthetic data from two different eddy-resolving models covering the North Atlantic Ocean and the Southern Ocean, respectively. The diagnosis shows that the mixing length assumption together with the definition of eddy length scales is valid within certain limitations. Furthermore, implementation of the closure in non-eddy-resolving models of the North Atlantic and the Southern Ocean shows consistently that the closure has skill at reproducing the results of the eddy-resolving model versions in terms of EKE and K. |
format |
Article in Journal/Newspaper |
author |
Eden, Carsten Greatbatch, Richard |
spellingShingle |
Eden, Carsten Greatbatch, Richard Towards a mesoscale eddy closure |
author_facet |
Eden, Carsten Greatbatch, Richard |
author_sort |
Eden, Carsten |
title |
Towards a mesoscale eddy closure |
title_short |
Towards a mesoscale eddy closure |
title_full |
Towards a mesoscale eddy closure |
title_fullStr |
Towards a mesoscale eddy closure |
title_full_unstemmed |
Towards a mesoscale eddy closure |
title_sort |
towards a mesoscale eddy closure |
publisher |
Elsevier |
publishDate |
2008 |
url |
https://oceanrep.geomar.de/id/eprint/2504/ https://oceanrep.geomar.de/id/eprint/2504/1/Eden.pdf https://doi.org/10.1016/j.ocemod.2007.09.002 |
geographic |
Southern Ocean |
geographic_facet |
Southern Ocean |
genre |
North Atlantic Southern Ocean |
genre_facet |
North Atlantic Southern Ocean |
op_relation |
https://oceanrep.geomar.de/id/eprint/2504/1/Eden.pdf Eden, C. and Greatbatch, R. (2008) Towards a mesoscale eddy closure. Ocean Modelling, 20 (3). pp. 223-239. DOI 10.1016/j.ocemod.2007.09.002 <https://doi.org/10.1016/j.ocemod.2007.09.002>. doi:10.1016/j.ocemod.2007.09.002 |
op_rights |
info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.1016/j.ocemod.2007.09.002 |
container_title |
Ocean Modelling |
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20 |
container_issue |
3 |
container_start_page |
223 |
op_container_end_page |
239 |
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1766127981526253568 |