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  • 1
    Online Resource
    Online Resource
    The Interaction of an Eastward-Flowing Current and an Island: Sub- and Supercritical Flow
    American Meteorological Society ; 2015
    In:  Journal of Physical Oceanography Vol. 45, No. 11 ( 2015-11), p. 2806-2819
    Details
    In: Journal of Physical Oceanography, American Meteorological Society, Vol. 45, No. 11 ( 2015-11), p. 2806-2819
    Abstract: An eastward-flowing current of a homogeneous fluid with velocity U , contained in a channel of width L , impinges on an island of width of O ( L ), and the resulting interaction and dynamics are studied for values of the supercriticality parameter, b = βL 2 / U , both larger and smaller than π 2 . The former case is subcritical with respect to Rossby waves, and the latter is supercritical. The nature of the flow field depends strongly on b , and in particular, the nature of the flow around the island and the proportion of the flow passing to the north or south of the island are sensitive to b and to the position of the island in the channel. The problem is studied analytically in a relatively simple, nonlinear quasigeostrophic and adiabatic framework and numerically with a shallow-water model that allows a qualitative extension of the results to the equator. Although the issues involved are motivated by the interaction of the Equatorial Undercurrent and the Galapagos Islands, the analysis presented here focuses on the fundamental issue of the distinctive nature of the flow as a function of Rossby wave criticality.
    Type of Medium: Online Resource
    ISSN: 0022-3670 , 1520-0485
    URL: Article
    DOI: 10.1175/JPO-D-15-0061.1
    Language: Unknown
    Publisher: American Meteorological Society
    Publication Date: 2015
    detail.hit.zdb_id: 2042184-9
    detail.hit.zdb_id: 184162-2
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  • 2
    Online Resource
    Online Resource
    Reflection and Transmission of Equatorial Rossby Waves*
    American Meteorological Society ; 2005
    In:  Journal of Physical Oceanography Vol. 35, No. 3 ( 2005-03-01), p. 363-373
    Details
    In: Journal of Physical Oceanography, American Meteorological Society, Vol. 35, No. 3 ( 2005-03-01), p. 363-373
    Abstract: The interaction of equatorial Rossby waves with a western boundary perforated with one or more narrow gaps is investigated using a shallow-water numerical model and supporting theory. It is found that very little of the incident energy flux is reflected into eastward-propagating equatorial Kelvin waves provided that at least one gap is located within approximately a deformation radius of the equator. Because of the circulation theorem around an island, the existence of a second gap off the equator reduces the reflection of short Rossby waves and enhances the transmission of the incident energy into the western basin. The westward energy transmitted past the easternmost island is further reduced upon encountering islands to the west, even if these islands are located entirely within the “shadow” of the easternmost island. A localized patch of wind forcing was also used to generate low-frequency Rossby waves for cases with island configurations representative of the western equatorial Pacific. For both idealized islands and a coastline based on the 200-m isobath, the amount of incident energy reflected into Kelvin waves depends on both the duration of the wind event and the meridional decay scale of the anomalous winds. For wind events of 2-yr duration with a meridional decay scale of 700 km, the reflected energy is 37% of the incident flux, and the energy transmitted into the Indian Ocean is approximately 10% of the incident flux, very close to that predicted by previous theories. For shorter wind events or winds confined more closely to the equator the reflected energy is significantly less.
    Type of Medium: Online Resource
    ISSN: 1520-0485 , 0022-3670
    URL: Article
    DOI: 10.1175/JPO-2691.1
    Language: English
    Publisher: American Meteorological Society
    Publication Date: 2005
    detail.hit.zdb_id: 2042184-9
    detail.hit.zdb_id: 184162-2
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  • 3
    Online Resource
    Online Resource
    Boundary Intensification of Vertical Velocity in a β-Plane Basin
    American Meteorological Society ; 2005
    In:  Journal of Physical Oceanography Vol. 35, No. 12 ( 2005-12-01), p. 2487-2500
    Details
    In: Journal of Physical Oceanography, American Meteorological Society, Vol. 35, No. 12 ( 2005-12-01), p. 2487-2500
    Abstract: The buoyancy-driven circulation of simple two-layer models on the β plane is studied in order to examine the role of beta in determining the magnitude and structure of the vertical motions forced in response to surface heating and cooling. Both analytical and numerical approaches are used to describe the change in circulation pattern and strength as a consequence of the planetary vorticity gradient. The physics is quasigeostrophic at lowest order but is sensitive to small nonquasigeostrophic mass fluxes across the boundary of the basin. The height of the interface between the two layers serves as an analog of temperature, and the vertical velocity at the interface consists of a cross-isopycnal velocity, modeled in terms of a relaxation to a prescribed interface height, as well as an adiabatic representation of eddy thickness fluxes parameterized as lateral diffusion of interface displacement. In the numerical model the lateral eddy diffusion of heat is explicitly represented by a resolved eddy field. In the plausibly more realistic case, when the lateral diffusion of buoyancy dominates the diffusion of momentum, the major vertical velocities occur at the boundary of the basin as in earlier f-plane studies. The effect of the planetary vorticity gradient is to intensify the sinking at the western wall and to enhance the magnitude of that sinking with respect to the f-plane models. The vertical mass flux in the Sverdrup interior exactly balances the vertical flux in the region of the strong horizontal transport of the western boundary current, leaving the net flux to occur in a very narrow region near the western boundary tucked well within the western boundary current. On the other hand, if the lateral diffusion of heat is arbitrarily and unrealistically eliminated, the vertical mass flux is forced to occur in the interior. The circulation pattern is extremely sensitive to small net inflows or outflows across the basin perimeter. The cross-basin flux determines the interface height on the basin’s eastern boundary and affects the circulation pattern across the entire basin.
    Type of Medium: Online Resource
    ISSN: 1520-0485 , 0022-3670
    URL: Article
    DOI: 10.1175/JPO2832.1
    Language: English
    Publisher: American Meteorological Society
    Publication Date: 2005
    detail.hit.zdb_id: 2042184-9
    detail.hit.zdb_id: 184162-2
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  • 4
    Online Resource
    Online Resource
    Lateral Coupling in Baroclinically Unstable Flows
    American Meteorological Society ; 2008
    In:  Journal of Physical Oceanography Vol. 38, No. 6 ( 2008-06-01), p. 1267-1277
    Details
    In: Journal of Physical Oceanography, American Meteorological Society, Vol. 38, No. 6 ( 2008-06-01), p. 1267-1277
    Abstract: A two-layer quasigeostrophic model in a channel is used to study the influence of lateral displacements of regions of different sign mean potential vorticity gradient (Πy) on the growth rate and structure of linearly unstable waves. The mean state is very idealized, with a region of positive Πy in the upper layer and a region of negative Πy in the lower layer; elsewhere Πy is zero. The growth rate and structure of the model’s unstable waves are quite sensitive to the amount of overlap between the two regions. For large amounts of overlap (more than several internal deformation radii), the channel modes described by Phillips’ model are recovered. The growth rate decreases abruptly as the amount of overlap decreases below the internal deformation radius. However, unstable modes are also found for cases in which the two nonzero Πy regions are separated far apart. In these cases, the wavenumber of the unstable waves decreases such that the aspect ratio of the wave remains O(1). The waves are characterized by a large-scale barotropic component that has maximum amplitude near one boundary but extends all the way across the channel to the opposite boundary. Near the boundaries, the wave is of mixed barotropic–baroclinic structure with cross-front scales on the order of the internal deformation radius. The perturbation heat flux is concentrated near the nonzero Πy regions, but the perturbation momentum flux extends all the way across the channel. The perturbation fluxes act to reduce the isopycnal slopes near the channel boundaries and to transmit zonal momentum from the region of Πy & gt; 0 to the region on the opposite side of the channel where Πy & lt; 0. These nonzero perturbation momentum fluxes are found even for a mean state that has no lateral shear in the velocity field.
    Type of Medium: Online Resource
    ISSN: 1520-0485 , 0022-3670
    URL: Article
    DOI: 10.1175/2007JPO3906.1
    Language: English
    Publisher: American Meteorological Society
    Publication Date: 2008
    detail.hit.zdb_id: 2042184-9
    detail.hit.zdb_id: 184162-2
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  • 5
    Online Resource
    Online Resource
    Response to a Steady Poleward Outflow. Part I: The Linear, Quasigeostrophic Problem
    American Meteorological Society ; 2009
    In:  Journal of Physical Oceanography Vol. 39, No. 7 ( 2009-07-01), p. 1541-1550
    Details
    In: Journal of Physical Oceanography, American Meteorological Society, Vol. 39, No. 7 ( 2009-07-01), p. 1541-1550
    Abstract: The response of a zonal channel to a uniform, switched-on but subsequently steady poleward outflow is presented. An eastward coastal current with a Kelvin wave’s cross-shore structure is found to be generated instantly upon initiation of the outflow. The current is essentially in geostrophic balance everywhere except for the vicinity of the outflow channel mouth, where the streamlines must cross planetary vorticity contours to feed the current. The adjustment of this region generates a plume that propagates westward at Rossby wave speeds. The cross-shore structure of the plume varies with longitude, and at any given longitude it evolves with time. The authors show that the plume evolution can be understood both conceptually and quantitatively as the westward propagation of the Kelvin current’s meridional spectrum, with each spectral element propagating at its own Rossby wave group velocity.
    Type of Medium: Online Resource
    ISSN: 1520-0485 , 0022-3670
    URL: Article
    DOI: 10.1175/2008JPO3999.1
    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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  • 6
    Online Resource
    Online Resource
    A Three-Dimensional Inertial Model for Coastal Upwelling along Western Boundaries
    American Meteorological Society ; 2022
    In:  Journal of Physical Oceanography Vol. 52, No. 10 ( 2022-10), p. 2431-2444
    Details
    In: Journal of Physical Oceanography, American Meteorological Society, Vol. 52, No. 10 ( 2022-10), p. 2431-2444
    Abstract: A three-dimensional inertial model that conserves quasigeostrophic potential vorticity is proposed for wind-driven coastal upwelling along western boundaries. The dominant response to upwelling favorable winds is a surface-intensified baroclinic meridional boundary current with a subsurface countercurrent. The width of the current is not the baroclinic deformation radius but instead scales with the inertial boundary layer thickness while the depth scales as the ratio of the inertial boundary layer thickness to the baroclinic deformation radius. Thus, the boundary current scales depend on the stratification, wind stress, Coriolis parameter, and its meridional variation. In contrast to two-dimensional wind-driven coastal upwelling, the source waters that feed the Ekman upwelling are provided over the depth scale of this baroclinic current through a combination of onshore barotropic flow and from alongshore in the narrow boundary current. Topography forces an additional current whose characteristics depend on the topographic slope and width. For topography wider than the inertial boundary layer thickness the current is bottom intensified, while for narrow topography the current is wave-like in the vertical and trapped over the topography within the inertial boundary layer. An idealized primitive equation numerical model produces a similar baroclinic boundary current whose vertical length scale agrees with the theoretical scaling for both upwelling and downwelling favorable winds.
    Type of Medium: Online Resource
    ISSN: 0022-3670 , 1520-0485
    URL: Article
    DOI: 10.1175/JPO-D-22-0024.1
    Language: Unknown
    Publisher: American Meteorological Society
    Publication Date: 2022
    detail.hit.zdb_id: 2042184-9
    detail.hit.zdb_id: 184162-2
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  • 7
    Online Resource
    Online Resource
    Response to a Steady Poleward Outflow. Part II: Oscillations and Eddies
    American Meteorological Society ; 2009
    In:  Journal of Physical Oceanography Vol. 39, No. 7 ( 2009-07-01), p. 1551-1573
    Details
    In: Journal of Physical Oceanography, American Meteorological Society, Vol. 39, No. 7 ( 2009-07-01), p. 1551-1573
    Abstract: A conceptually simple model is presented for predicting the amplitude and periodicity of eddies generated by a steady poleward outflow in a 1½-layer β-plane formulation. The prediction model is rooted in linear quasigeostrophic dynamics but is capable of predicting the amplitude of the β plume generated by outflows in the nonlinear range. Oscillations in the plume amplitude are seen to represent a near-zero group velocity response to an adjustment process that can be traced back to linear dynamics. When the plume-amplitude oscillations become large enough so that the coherent β plume is replaced by a robust eddy field, the eddy amplitude is still constrained by the plume-amplitude prediction model. The eddy periodicity remains close to that of the predictable, near-zero group-velocity linear oscillations. Striking similarities between the patterns of variability in the model and observations south of Indonesia’s Lombok Strait suggest that the processes investigated in this study may play an important role in the generation of the observed eddy field of the Indo-Australian Basin.
    Type of Medium: Online Resource
    ISSN: 1520-0485 , 0022-3670
    URL: Article
    DOI: 10.1175/2008JPO4152.1
    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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  • 8
    Online Resource
    Online Resource
    Reply to “Comments on ‘The Interaction of an Eastward-Flowing Current and an Island: Sub- and Supercritical Flow’”
    American Meteorological Society ; 2016
    In:  Journal of Physical Oceanography Vol. 46, No. 7 ( 2016-07), p. 2267-2268
    Details
    In: Journal of Physical Oceanography, American Meteorological Society, Vol. 46, No. 7 ( 2016-07), p. 2267-2268
    Type of Medium: Online Resource
    ISSN: 0022-3670 , 1520-0485
    URL: Article
    DOI: 10.1175/JPO-D-16-0057.1
    Language: Unknown
    Publisher: American Meteorological Society
    Publication Date: 2016
    detail.hit.zdb_id: 2042184-9
    detail.hit.zdb_id: 184162-2
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  • 9
    Online Resource
    Online Resource
    The two-layer skirted island
    Journal of Marine Research/Yale ; 2011
    In:  Journal of Marine Research Vol. 69, No. 2 ( 2011-03-01), p. 347-382
    Details
    In: Journal of Marine Research, Journal of Marine Research/Yale, Vol. 69, No. 2 ( 2011-03-01), p. 347-382
    Type of Medium: Online Resource
    ISSN: 0022-2402
    URL: Article
    DOI: 10.1357/002224011798765222
    Language: English
    Publisher: Journal of Marine Research/Yale
    Publication Date: 2011
    detail.hit.zdb_id: 410655-6
    detail.hit.zdb_id: 2066603-2
    SSG: 12
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  • 10
    Online Resource
    Online Resource
    Circulation around islands and ridges
    Journal of Marine Research/Yale ; 1997
    In:  Journal of Marine Research Vol. 55, No. 6 ( 1997-11-01), p. 1199-1251
    Details
    In: Journal of Marine Research, Journal of Marine Research/Yale, Vol. 55, No. 6 ( 1997-11-01), p. 1199-1251
    Type of Medium: Online Resource
    ISSN: 0022-2402 , 1543-9542
    URL: Article
    DOI: 10.1357/0022240973224085
    Language: English
    Publisher: Journal of Marine Research/Yale
    Publication Date: 1997
    detail.hit.zdb_id: 410655-6
    detail.hit.zdb_id: 2066603-2
    SSG: 12
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