Understanding the regional variability of eddy diffusivity in the Pacific sector of the Southern Ocean
A diagnostic framework is presented, based on the Nakamura effective diffusivity, to investigate the regional variation in eddy diffusivity. Comparison of three different diffusivity calculations enables the effects of locally enhanced tracer diffusion to be distinguished from the streamwise average...
Published in: | Journal of Physical Oceanography |
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American Meteorological Society
2009
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Online Access: | http://nora.nerc.ac.uk/id/eprint/11276/ https://doi.org/10.1175/2009JPO4115.1 |
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ftnerc:oai:nora.nerc.ac.uk:11276 2023-05-15T18:24:45+02:00 Understanding the regional variability of eddy diffusivity in the Pacific sector of the Southern Ocean Shuckburgh, Emily Jones, Helen Marshall, John Hill, Chris 2009 http://nora.nerc.ac.uk/id/eprint/11276/ https://doi.org/10.1175/2009JPO4115.1 unknown American Meteorological Society Shuckburgh, Emily orcid:0000-0001-9206-3444 Jones, Helen; Marshall, John; Hill, Chris. 2009 Understanding the regional variability of eddy diffusivity in the Pacific sector of the Southern Ocean. Journal of Physical Oceanography, 39 (9). 2011-2023. https://doi.org/10.1175/2009JPO4115.1 <https://doi.org/10.1175/2009JPO4115.1> Marine Sciences Hydrology Publication - Article PeerReviewed 2009 ftnerc https://doi.org/10.1175/2009JPO4115.1 2023-02-04T19:27:17Z A diagnostic framework is presented, based on the Nakamura effective diffusivity, to investigate the regional variation in eddy diffusivity. Comparison of three different diffusivity calculations enables the effects of locally enhanced tracer diffusion to be distinguished from the streamwise average. It also enables the distinction to be made between locally generated complexity in the tracer structure and that advected into a particular domain. The technique is applied to the Pacific sector of the Southern Ocean. The results highlight the important role that the mean flow plays in determining eddy diffusivity. The effective diffusivity is not simply related to the eddy kinetic energy: in regions of a strong mean flow the eddy diffusivity can be suppressed even in the presence of moderately strong eddy activity; conversely, in a region of weak mean flow the eddy diffusivity can be enhanced even in the presence of only weak eddy activity. This casts doubt on the ability of parameterizations based solely on the eddy kinetic energy to adequately characterize the eddy diffusivity in regions of strongly varying mean flow such as the Southern Ocean. The results are, however, consistent with the eddy transport and mixing variability predicted by potential-vorticity-based arguments. Article in Journal/Newspaper Southern Ocean Natural Environment Research Council: NERC Open Research Archive Pacific Southern Ocean Journal of Physical Oceanography 39 9 2011 2023 |
institution |
Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
unknown |
topic |
Marine Sciences Hydrology |
spellingShingle |
Marine Sciences Hydrology Shuckburgh, Emily Jones, Helen Marshall, John Hill, Chris Understanding the regional variability of eddy diffusivity in the Pacific sector of the Southern Ocean |
topic_facet |
Marine Sciences Hydrology |
description |
A diagnostic framework is presented, based on the Nakamura effective diffusivity, to investigate the regional variation in eddy diffusivity. Comparison of three different diffusivity calculations enables the effects of locally enhanced tracer diffusion to be distinguished from the streamwise average. It also enables the distinction to be made between locally generated complexity in the tracer structure and that advected into a particular domain. The technique is applied to the Pacific sector of the Southern Ocean. The results highlight the important role that the mean flow plays in determining eddy diffusivity. The effective diffusivity is not simply related to the eddy kinetic energy: in regions of a strong mean flow the eddy diffusivity can be suppressed even in the presence of moderately strong eddy activity; conversely, in a region of weak mean flow the eddy diffusivity can be enhanced even in the presence of only weak eddy activity. This casts doubt on the ability of parameterizations based solely on the eddy kinetic energy to adequately characterize the eddy diffusivity in regions of strongly varying mean flow such as the Southern Ocean. The results are, however, consistent with the eddy transport and mixing variability predicted by potential-vorticity-based arguments. |
format |
Article in Journal/Newspaper |
author |
Shuckburgh, Emily Jones, Helen Marshall, John Hill, Chris |
author_facet |
Shuckburgh, Emily Jones, Helen Marshall, John Hill, Chris |
author_sort |
Shuckburgh, Emily |
title |
Understanding the regional variability of eddy diffusivity in the Pacific sector of the Southern Ocean |
title_short |
Understanding the regional variability of eddy diffusivity in the Pacific sector of the Southern Ocean |
title_full |
Understanding the regional variability of eddy diffusivity in the Pacific sector of the Southern Ocean |
title_fullStr |
Understanding the regional variability of eddy diffusivity in the Pacific sector of the Southern Ocean |
title_full_unstemmed |
Understanding the regional variability of eddy diffusivity in the Pacific sector of the Southern Ocean |
title_sort |
understanding the regional variability of eddy diffusivity in the pacific sector of the southern ocean |
publisher |
American Meteorological Society |
publishDate |
2009 |
url |
http://nora.nerc.ac.uk/id/eprint/11276/ https://doi.org/10.1175/2009JPO4115.1 |
geographic |
Pacific Southern Ocean |
geographic_facet |
Pacific Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_relation |
Shuckburgh, Emily orcid:0000-0001-9206-3444 Jones, Helen; Marshall, John; Hill, Chris. 2009 Understanding the regional variability of eddy diffusivity in the Pacific sector of the Southern Ocean. Journal of Physical Oceanography, 39 (9). 2011-2023. https://doi.org/10.1175/2009JPO4115.1 <https://doi.org/10.1175/2009JPO4115.1> |
op_doi |
https://doi.org/10.1175/2009JPO4115.1 |
container_title |
Journal of Physical Oceanography |
container_volume |
39 |
container_issue |
9 |
container_start_page |
2011 |
op_container_end_page |
2023 |
_version_ |
1766205609276866560 |