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  • 1
    Online Resource
    Online Resource
    Effective Eddy Diffusivities Inferred from a Point Release Tracer in an Eddy-Resolving Ocean Model
    American Meteorological Society ; 2009
    In:  Journal of Physical Oceanography Vol. 39, No. 4 ( 2009-04-01), p. 894-914
    Details
    In: Journal of Physical Oceanography, American Meteorological Society, Vol. 39, No. 4 ( 2009-04-01), p. 894-914
    Abstract: This study uses tracer experiments in a global eddy-resolving ocean model to examine two diagnostic methods for inferring effective eddy isopycnic diffusivity from point release tracers. The first method is based on the growth rate of the area occupied by the tracers (the equivalent variance). During the period when tracer dispersion is dominated by stirring, the equivalent variance is found to increase at a rate between the second power law (for a pure shearing flow regime) and the exponential law (for a pure stretching flow regime). The second method is based on the length of the tracer contours. In the framework of equivalent radius, the two methods of inferring eddy diffusivity can be understood as two different averagings over the tracer patch. Over a shorter period of tracer dispersion the two methods give different eddy diffusivities, and only over a longer time when tracer dispersion approaches the final stage of diffusion do they give a similar value of diffusivity. A new diagnostic quantity called stirring efficiency is introduced to indicate different flow regimes by measuring the efficiency of stirring against mixing. The new diagnostic quantity has the advantage that it can be calculated directly from the gradients of tracer distribution without needing to estimate strain rate or background diffusivity.
    Type of Medium: Online Resource
    ISSN: 1520-0485 , 0022-3670
    URL: Article
    DOI: 10.1175/2008JPO3902.1
    Language: English
    Publisher: American Meteorological Society
    Publication Date: 2009
    detail.hit.zdb_id: 2042184-9
    detail.hit.zdb_id: 184162-2
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  • 2
    Online Resource
    Online Resource
    Subduction over the Southern Indian Ocean in a High-Resolution Atmosphere–Ocean Coupled Model
    American Meteorological Society ; 2011
    In:  Journal of Climate Vol. 24, No. 15 ( 2011-08-01), p. 3830-3849
    Details
    In: Journal of Climate, American Meteorological Society, Vol. 24, No. 15 ( 2011-08-01), p. 3830-3849
    Abstract: This study examines the subduction of the Subantarctic Mode Water in the Indian Ocean in an ocean–atmosphere coupled model in which the ocean component is eddy permitting. The purpose is to assess how sensitive the simulated mode water is to the horizontal resolution in the ocean by comparing with a coarse-resolution ocean coupled model. Subduction of water mass is principally set by the depth of the winter mixed layer. It is found that the path of the Agulhas Current system in the model with an eddy-permitting ocean is different from that with a coarse-resolution ocean. This results in a greater surface heat loss over the Agulhas Return Current and a deeper winter mixed layer downstream in the eddy-permitting ocean coupled model. The winter mixed layer depth in the eddy-permitting ocean compares well to the observations, whereas the winter mixed layer depth in the coarse-resolution ocean coupled model is too shallow and has the wrong spatial structure. To quantify the impacts of different winter mixed depths on the subduction, a way to diagnose local subduction is proposed that includes eddy subduction. It shows that the subduction in the eddy-permitting model is closer to the observations in terms of the magnitudes and the locations. Eddies in the eddy-permitting ocean are found to 1) increase stratification and thus oppose the densification by northward Ekman flow and 2) increase subduction locally. These effects of eddies are not well reproduced by the eddy parameterization in the coarse-resolution ocean coupled model.
    Type of Medium: Online Resource
    ISSN: 0894-8755 , 1520-0442
    URL: Article
    DOI: 10.1175/2011JCLI3888.1
    RVK:
    UA 4548
    Language: English
    Publisher: American Meteorological Society
    Publication Date: 2011
    detail.hit.zdb_id: 246750-1
    detail.hit.zdb_id: 2021723-7
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  • 3
    Online Resource
    Online Resource
    On the Relationship between Subduction Rates and Diabatic Forcing of the Mixed Layer
    American Meteorological Society ; 1991
    In:  Journal of Physical Oceanography Vol. 21, No. 12 ( 1991-12), p. 1793-1802
    Details
    In: Journal of Physical Oceanography, American Meteorological Society, Vol. 21, No. 12 ( 1991-12), p. 1793-1802
    Type of Medium: Online Resource
    ISSN: 0022-3670 , 1520-0485
    URL: Article
    DOI: 10.1175/1520-0485(1991)021〈1793:OTRBSR〉2.0.CO;2
    Language: English
    Publisher: American Meteorological Society
    Publication Date: 1991
    detail.hit.zdb_id: 2042184-9
    detail.hit.zdb_id: 184162-2
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  • 4
    Online Resource
    Online Resource
    The Impact of Small-Scale Topography on the Dynamical Balance of the Ocean
    American Meteorological Society ; 2013
    In:  Journal of Physical Oceanography Vol. 43, No. 3 ( 2013-03-01), p. 647-668
    Details
    In: Journal of Physical Oceanography, American Meteorological Society, Vol. 43, No. 3 ( 2013-03-01), p. 647-668
    Abstract: The impact of small-scale topography on the ocean’s dynamical balance is investigated by quantifying the rates at which internal wave drag extracts (angular) momentum and vorticity from the general circulation. The calculation exploits the recent advent of two near-global descriptions of topographic roughness on horizontal scales on the order of 1–10 km, which play a central role in the generation of internal lee waves by geostrophic flows impinging on topography and have been hitherto unresolved by bathymetric datasets and ocean general circulation models alike. It is found that, while internal wave drag is a minor contributor to the ocean’s dynamical balance over much of the globe, it is a significant player in the dynamics of extensive areas of the ocean, most notably the Antarctic Circumpolar Current and several regions of enhanced small-scale topographic variance in the equatorial and Southern Hemisphere oceans. There, the contribution of internal wave drag to the ocean’s (angular) momentum and vorticity balances is generally on the order of ten to a few tens of percent of the dominant source and sink terms in each dynamical budget, which are respectively associated with wind forcing and form drag by topography with horizontal scales from 500 to 1000 km. It is thus suggested that the representation of internal wave drag in general circulation models may lead to significant changes in the deep ocean circulation of those regions. A theoretical scaling is derived that captures the basic dependence of internal wave drag on topographic roughness and near-bottom flow speed for most oceanographically relevant regimes.
    Type of Medium: Online Resource
    ISSN: 0022-3670 , 1520-0485
    URL: Article
    DOI: 10.1175/JPO-D-12-056.1
    Language: English
    Publisher: American Meteorological Society
    Publication Date: 2013
    detail.hit.zdb_id: 2042184-9
    detail.hit.zdb_id: 184162-2
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  • 5
    Online Resource
    Online Resource
    Fluid Dynamics of Oceanic Thermocline Ventilation
    American Meteorological Society ; 1992
    In:  Journal of Physical Oceanography Vol. 22, No. 6 ( 1992-06), p. 583-595
    Details
    In: Journal of Physical Oceanography, American Meteorological Society, Vol. 22, No. 6 ( 1992-06), p. 583-595
    Type of Medium: Online Resource
    ISSN: 0022-3670 , 1520-0485
    URL: Article
    DOI: 10.1175/1520-0485(1992)022〈0583:FDOOTV〉2.0.CO;2
    Language: English
    Publisher: American Meteorological Society
    Publication Date: 1992
    detail.hit.zdb_id: 2042184-9
    detail.hit.zdb_id: 184162-2
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  • 6
    Online Resource
    Online Resource
    Spurious Diapycnal Mixing of the Deep Waters in an Eddy-Permitting Global Ocean Model
    American Meteorological Society ; 2002
    In:  Journal of Physical Oceanography Vol. 32, No. 5 ( 2002-05), p. 1522-1535
    Details
    In: Journal of Physical Oceanography, American Meteorological Society, Vol. 32, No. 5 ( 2002-05), p. 1522-1535
    Type of Medium: Online Resource
    ISSN: 0022-3670 , 1520-0485
    URL: Article
    DOI: 10.1175/1520-0485(2002)032〈1522:SDMOTD〉2.0.CO;2
    Language: English
    Publisher: American Meteorological Society
    Publication Date: 2002
    detail.hit.zdb_id: 2042184-9
    detail.hit.zdb_id: 184162-2
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  • 7
    Online Resource
    Online Resource
    The Effects on Ocean Models of Relaxation toward Observations at the Surface
    American Meteorological Society ; 2000
    In:  Journal of Physical Oceanography Vol. 30, No. 1 ( 2000-01), p. 160-174
    Details
    In: Journal of Physical Oceanography, American Meteorological Society, Vol. 30, No. 1 ( 2000-01), p. 160-174
    Type of Medium: Online Resource
    ISSN: 0022-3670 , 1520-0485
    URL: Article
    DOI: 10.1175/1520-0485(2000)030〈0160:TEOOMO〉2.0.CO;2
    Language: English
    Publisher: American Meteorological Society
    Publication Date: 2000
    detail.hit.zdb_id: 2042184-9
    detail.hit.zdb_id: 184162-2
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  • 8
    Online Resource
    Online Resource
    Eddy Advective and Diffusive Transports of Heat and Salt in the Southern Ocean
    American Meteorological Society ; 2007
    In:  Journal of Physical Oceanography Vol. 37, No. 5 ( 2007-05-01), p. 1376-1393
    Details
    In: Journal of Physical Oceanography, American Meteorological Society, Vol. 37, No. 5 ( 2007-05-01), p. 1376-1393
    Abstract: There are two distinct mechanisms by which eddies provide systematic transport of tracer on isopycnals: the advective transport, associated with the slumping of isopycnals, and the diffusive transport, associated with down-gradient diffusion. Depending on the large-scale tracer distribution, eddy advective transport has either the same direction as or opposite direction to eddy diffusive transport. As a consequence, eddy advection and eddy diffusion can reinforce each other for some tracers but oppose each other for other tracers. Using scaling analysis, it is argued that the relative directions of eddy advective and diffusive transports can be determined simply from the relative slopes of tracers and isopycnals. An eddy-resolving (1/12°) global ocean model is used to illustrate the two eddy transport mechanisms for temperature and salinity in the Southern Ocean. Applications to other tracers, such as oxygen, are discussed. The diagnosed eddy diffusivity for temperature (and salinity) is found to be considerably different from the eddy diffusivity for eddy advective transport velocity.
    Type of Medium: Online Resource
    ISSN: 1520-0485 , 0022-3670
    URL: Article
    DOI: 10.1175/JPO3057.1
    Language: English
    Publisher: American Meteorological Society
    Publication Date: 2007
    detail.hit.zdb_id: 2042184-9
    detail.hit.zdb_id: 184162-2
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  • 9
    Online Resource
    Online Resource
    Eddy Subduction and the Vertical Transport Streamfunction
    American Meteorological Society ; 2012
    In:  Journal of Physical Oceanography Vol. 42, No. 11 ( 2012-11-01), p. 1762-1780
    Details
    In: Journal of Physical Oceanography, American Meteorological Society, Vol. 42, No. 11 ( 2012-11-01), p. 1762-1780
    Abstract: Subduction—the transport of fluid across the base of mixed layer—exchanges water masses and tracers between the ocean surface and interior. Eddies can affect subduction in a variety of ways. First, eddies shoal the mixed layer by restratifying water columns through baroclinic instabilities. Second, eddies induce an isopycnic transport that leads to the entrainment of warm waters and subduction of cold waters, which effectively counters the wind-driven overturning circulation. In this study, the authors use an idealized model to examine these two mechanisms by which eddies influence subduction and to discuss how eddy subduction may be better approximated using the concept of vertical transport streamfunction than the conventional meridional transport streamfunction.
    Type of Medium: Online Resource
    ISSN: 0022-3670 , 1520-0485
    URL: Article
    DOI: 10.1175/JPO-D-11-0219.1
    Language: English
    Publisher: American Meteorological Society
    Publication Date: 2012
    detail.hit.zdb_id: 2042184-9
    detail.hit.zdb_id: 184162-2
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  • 10
    Online Resource
    Online Resource
    A model of secondary upwelling over the shelf break. II
    Informa UK Limited ; 1984
    In:  Geophysical & Astrophysical Fluid Dynamics Vol. 28, No. 2 ( 1984-03), p. 161-170
    Details
    In: Geophysical & Astrophysical Fluid Dynamics, Informa UK Limited, Vol. 28, No. 2 ( 1984-03), p. 161-170
    Type of Medium: Online Resource
    ISSN: 0309-1929 , 1029-0419
    URL: Article
    DOI: 10.1080/03091928408222848
    Language: English
    Publisher: Informa UK Limited
    Publication Date: 1984
    detail.hit.zdb_id: 2025363-1
    SSG: 16,13
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