Understanding the Regional Variability of Eddy Diffusivity in the Pacific Sector of the Southern Ocean
Name
Shuckburgh-2009-Understanding the Re.pdf
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8.34 MB
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Checksum (MD5)
03f2bc203707a478b20ccc146eb5b603
Author(s)
Shuckburgh, Emily
Hill, Christopher N.
Marshall, John C.
Jones, Helen
Date Issued
February 2009
Journal
Journal of Physical Oceanography
Publisher
American Meteorological Society
Citation
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.
Version
Final published version
Abstract
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.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
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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.
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DOI of Published Version
http://dx.doi.org/10.1175/2009jpo4115.1
