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...
| Main Authors: | , , , |
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| Other Authors: | |
| Format: | Article |
| Language: | en_US |
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American Meteorological Society
2010
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| Online Access: | http://hdl.handle.net/1721.1/54734 https://orcid.org/0000-0001-9230-3591 |
| _version_ | 1811077490474483712 |
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| author | Shuckburgh, Emily Hill, Christopher N. Marshall, John C. Jones, Helen |
| author2 | Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences |
| author_facet | Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Shuckburgh, Emily Hill, Christopher N. Marshall, John C. Jones, Helen |
| author_sort | Shuckburgh, Emily |
| collection | MIT |
| 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. |
| first_indexed | 2024-09-23T10:43:51Z |
| format | Article |
| id | mit-1721.1/54734 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T10:43:51Z |
| publishDate | 2010 |
| publisher | American Meteorological Society |
| record_format | dspace |
| spelling | mit-1721.1/547342024-07-12T20:21:46Z Understanding the Regional Variability of Eddy Diffusivity in the Pacific Sector of the Southern Ocean Shuckburgh, Emily Hill, Christopher N. Marshall, John C. Jones, Helen Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Marshall, John C. Hill, Christopher N. Marshall, John C. Jones, Helen 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. 2010-05-07T20:10:57Z 2010-05-07T20:10:57Z 2009-02 2008-08 Article http://purl.org/eprint/type/JournalArticle 0022-3670 1520-0485 http://hdl.handle.net/1721.1/54734 Shuckburgh, Emily et al. “Understanding the Regional Variability of Eddy Diffusivity in the Pacific Sector of the Southern Ocean.” Journal of Physical Oceanography 39.9 (2009): 2011-2023. © 2009 American Meteorological Society. https://orcid.org/0000-0001-9230-3591 en_US http://dx.doi.org/10.1175/2009jpo4115.1 Journal of Physical Oceanography Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf American Meteorological Society American Meteorological Society |
| spellingShingle | Shuckburgh, Emily Hill, Christopher N. Marshall, John C. Jones, Helen Understanding the Regional Variability of Eddy Diffusivity in the Pacific Sector of the Southern Ocean |
| title | 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_short | 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 |
| url | http://hdl.handle.net/1721.1/54734 https://orcid.org/0000-0001-9230-3591 |
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