Diagnostics of isopycnal mixing in a circumpolar channel
Mesoscale eddies mix tracers along isopycnals and horizontally at the sea surface. This paper compares different methods of diagnosing eddy mixing rates in an idealized, eddy-resolving model of a channel flow meant to resemble the Antarctic Circumpolar Current. The first set of methods, the ‘‘perfec...
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ftunivreading:oai:centaur.reading.ac.uk:88146 2024-09-09T19:06:07+00:00 Diagnostics of isopycnal mixing in a circumpolar channel Abernathey, Ryan Ferreira, David Klocker, Andreas 2013-12 https://centaur.reading.ac.uk/88146/ unknown Elsevier Abernathey, R., Ferreira, D. <https://centaur.reading.ac.uk/view/creators/90005370.html> orcid:0000-0003-3243-9774 and Klocker, A. (2013) Diagnostics of isopycnal mixing in a circumpolar channel. Ocean Modelling, 72. pp. 1-16. ISSN 1463-5003 doi: https://doi.org/10.1016/j.ocemod.2013.07.004 <https://doi.org/10.1016/j.ocemod.2013.07.004> Article PeerReviewed 2013 ftunivreading https://doi.org/10.1016/j.ocemod.2013.07.004 2024-06-25T15:03:04Z Mesoscale eddies mix tracers along isopycnals and horizontally at the sea surface. This paper compares different methods of diagnosing eddy mixing rates in an idealized, eddy-resolving model of a channel flow meant to resemble the Antarctic Circumpolar Current. The first set of methods, the ‘‘perfect’’ diag- nostics, are techniques suitable only to numerical models, in which detailed synoptic data is available. The perfect diagnostic include flux-gradient diffusivities of buoyancy, QGPV, and Ertel PV; Nakamura effective diffusivity; and the four-element diffusivity tensor calculated from an ensemble of passive tracers. These diagnostics reveal a consistent picture of isopycnal mixing by eddies, with a pronounced maximum near 1000 m depth. The isopycnal diffusivity differs from the buoyancy diffusivity, a.k.a. the Gent–McWilliams transfer coefficient, which is weaker and peaks near the surface and bottom. The sec- ond set of methods are observationally ‘‘practical’’ diagnostics. They involve monitoring the spreading of tracers or Lagrangian particles in ways that are plausible in the field. We show how, with sufficient ensemble size, the practical diagnostics agree with the perfect diagnostics in an average sense. Some implications for eddy parameterization are discussed. Article in Journal/Newspaper Antarc* Antarctic CentAUR: Central Archive at the University of Reading Antarctic The Antarctic Ocean Modelling 72 1 16 |
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Open Polar |
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CentAUR: Central Archive at the University of Reading |
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ftunivreading |
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Mesoscale eddies mix tracers along isopycnals and horizontally at the sea surface. This paper compares different methods of diagnosing eddy mixing rates in an idealized, eddy-resolving model of a channel flow meant to resemble the Antarctic Circumpolar Current. The first set of methods, the ‘‘perfect’’ diag- nostics, are techniques suitable only to numerical models, in which detailed synoptic data is available. The perfect diagnostic include flux-gradient diffusivities of buoyancy, QGPV, and Ertel PV; Nakamura effective diffusivity; and the four-element diffusivity tensor calculated from an ensemble of passive tracers. These diagnostics reveal a consistent picture of isopycnal mixing by eddies, with a pronounced maximum near 1000 m depth. The isopycnal diffusivity differs from the buoyancy diffusivity, a.k.a. the Gent–McWilliams transfer coefficient, which is weaker and peaks near the surface and bottom. The sec- ond set of methods are observationally ‘‘practical’’ diagnostics. They involve monitoring the spreading of tracers or Lagrangian particles in ways that are plausible in the field. We show how, with sufficient ensemble size, the practical diagnostics agree with the perfect diagnostics in an average sense. Some implications for eddy parameterization are discussed. |
format |
Article in Journal/Newspaper |
author |
Abernathey, Ryan Ferreira, David Klocker, Andreas |
spellingShingle |
Abernathey, Ryan Ferreira, David Klocker, Andreas Diagnostics of isopycnal mixing in a circumpolar channel |
author_facet |
Abernathey, Ryan Ferreira, David Klocker, Andreas |
author_sort |
Abernathey, Ryan |
title |
Diagnostics of isopycnal mixing in a circumpolar channel |
title_short |
Diagnostics of isopycnal mixing in a circumpolar channel |
title_full |
Diagnostics of isopycnal mixing in a circumpolar channel |
title_fullStr |
Diagnostics of isopycnal mixing in a circumpolar channel |
title_full_unstemmed |
Diagnostics of isopycnal mixing in a circumpolar channel |
title_sort |
diagnostics of isopycnal mixing in a circumpolar channel |
publisher |
Elsevier |
publishDate |
2013 |
url |
https://centaur.reading.ac.uk/88146/ |
geographic |
Antarctic The Antarctic |
geographic_facet |
Antarctic The Antarctic |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_relation |
Abernathey, R., Ferreira, D. <https://centaur.reading.ac.uk/view/creators/90005370.html> orcid:0000-0003-3243-9774 and Klocker, A. (2013) Diagnostics of isopycnal mixing in a circumpolar channel. Ocean Modelling, 72. pp. 1-16. ISSN 1463-5003 doi: https://doi.org/10.1016/j.ocemod.2013.07.004 <https://doi.org/10.1016/j.ocemod.2013.07.004> |
op_doi |
https://doi.org/10.1016/j.ocemod.2013.07.004 |
container_title |
Ocean Modelling |
container_volume |
72 |
container_start_page |
1 |
op_container_end_page |
16 |
_version_ |
1809820142739128320 |