Pacific low-latitude western boundary currents and the Indonesian throughflow

1996 ◽  
Vol 101 (C5) ◽  
pp. 12209-12216 ◽  
Author(s):  
Roger Lukas ◽  
Toshio Yamagata ◽  
Julian P. McCreary
Keyword(s):  
Western Boundary ◽  
Indonesian Throughflow ◽  
Low Latitude ◽  
Western Boundary Currents ◽  
Boundary Currents

scholarly journals Dynamics of turbulent western-boundary currents at low latitude in a shallow-water model

Ocean Science ◽  
2015 ◽  
Vol 11 (3) ◽  
pp. 471-481 ◽  
Author(s):  
C. Q. C. Akuetevi ◽  
A. Wirth
Keyword(s):  
Boundary Layer ◽  
Shallow Water ◽  
Numerical Models ◽  
Water Model ◽  
Western Boundary ◽  
Advective Transport ◽  
Shallow Water Model ◽  
Low Latitude ◽  
Western Boundary Currents ◽  
Boundary Currents

Abstract. The dynamics of low latitude turbulent western-boundary currents (WBCs) crossing the Equator are considered using numerical results from integrations of a reduced-gravity shallow-water model. For viscosity values of 1000 m2 s−1 and greater, the boundary layer dynamics compares well to the analytical Munk-layer solution. When the viscosity is reduced, the boundary layer becomes turbulent and coherent structures in the form of anticyclonic eddies, bursts (violent detachments of the viscous sub-layer, VSL) and dipoles appear. Three distinct boundary layers emerge, the VSL, the advective boundary layer and the extended boundary layer. The first is characterized by a dominant vorticity balance between the viscous transport and the advective transport of vorticity; the second by a balance between the advection of planetary vorticity and the advective transport of relative vorticity. The extended boundary layer is the area to which turbulent motion from the boundary extends. The scaling of the three boundary layer thicknesses with viscosity is evaluated. Characteristic scales of the dynamics and dissipation are determined. A pragmatic approach to determine the eddy viscosity diagnostically for coarse-resolution numerical models is proposed.

scholarly journals Dynamics of turbulent western boundary currents at low latitude in a shallow water model

2014 ◽  
Vol 11 (2) ◽  
pp. 753-788 ◽  
Author(s):  
C. Q. C. Akuetevi ◽  
A. Wirth
Keyword(s):  
Boundary Layer ◽  
Shallow Water ◽  
Water Model ◽  
Trade Wind ◽  
Western Boundary ◽  
Advective Transport ◽  
Shallow Water Model ◽  
Low Latitude ◽  
Western Boundary Currents ◽  
Boundary Currents

Abstract. The dynamics of low latitude turbulent western boundary currents, subject to two different types of idealized wind forcing, Monsoon Wind and Trade Wind, is considered using numerical results from integrations of a reduced gravity shallow-water model. For viscosity values of 1000 m2 s−1 and above, the boundary layer dynamics compares well to the analytical solutions of the Munk-layer and the inertial-layer, derived from quasigeostrophic theory. Modifications due to variations in the layer thickness (vortex stretching) are only important close to the boundary. When the viscosity is reduced the boundary layer becomes turbulent and coherent structures in form of anticyclonic eddies, bursts (violent detachments of the viscous sub-layer) and dipoles appear. Three distinct boundary layers emerge, the viscous sub-layer, the advective boundary layer and the extended boundary layer. The first is characterized by a dominant vorticity balance between the viscous transport and the advective transport of vorticity. The second by a balance between the advection of planetary vorticity and the advective transport of relative vorticity. The extended boundary layer is the area to which turbulent motion from the boundary extends. The scaling of the three boundary layer thicknesses with viscosity is evaluated. A pragmatic approach to determine the eddy viscosity diagnostically for coarse resolution numerical models is proposed.

scholarly journals Dynamics of turbulent western boundary currents at low latitude in a shallow water model

2014 ◽  
Vol 11 (6) ◽  
pp. 2461-2493
Author(s):  
C. Q. C. Akuetevi ◽  
A. Wirth
Keyword(s):  
Boundary Layer ◽  
Shallow Water ◽  
Numerical Models ◽  
Water Model ◽  
Western Boundary ◽  
Advective Transport ◽  
Shallow Water Model ◽  
Low Latitude ◽  
Western Boundary Currents ◽  
Boundary Currents

Abstract. The dynamics of low latitude turbulent western boundary currents crossing the equator is considered using numerical results from integrations of a reduced gravity shallow-water model. For viscosity values of 1000 m2 s−1 and more, the boundary layer dynamics compares well to the analytical Munk-layer solution. When the viscosity is reduced, the boundary layer becomes turbulent and coherent structures in form of anticyclonic eddies, bursts (violent detachments of the viscous sub-layer) and dipoles appear. Three distinct boundary layers emerge, the viscous sub-layer, the advective boundary layer and the extended boundary layer. The first is characterized by a dominant vorticity balance between the viscous transport and the advective transport of vorticity. The second by a balance between the advection of planetary vorticity and the advective transport of relative vorticity. The extended boundary layer is the area to which turbulent motion from the boundary extends. The scaling of the three boundary layer thicknesses with viscosity is evaluated. Characteristic scales of the dynamics and dissipation are determined. A pragmatic approach to determine the eddy viscosity diagnostically for coarse resolution numerical models is proposed.

scholarly journals Radiating Instability of a Meridional Boundary Current

2008 ◽  
Vol 38 (10) ◽  
pp. 2294-2307 ◽  
Author(s):  
Hristina G. Hristova ◽  
Joseph Pedlosky ◽  
Michael A. Spall
Keyword(s):  
Western Boundary ◽  
Far Field ◽  
Boundary Current ◽  
Important Conclusion ◽  
Western Boundary Currents ◽  
Horizontal Structure ◽  
Boundary Currents ◽  
Zonal Jets ◽  
Eastern Boundary ◽  
Eastern Boundary Current

Abstract A linear stability analysis of a meridional boundary current on the beta plane is presented. The boundary current is idealized as a constant-speed meridional jet adjacent to a semi-infinite motionless far field. The far-field region can be situated either on the eastern or the western side of the jet, representing a western or an eastern boundary current, respectively. It is found that when unstable, the meridional boundary current generates temporally growing propagating waves that transport energy away from the locally unstable region toward the neutral far field. This is the so-called radiating instability and is found in both barotropic and two-layer baroclinic configurations. A second but important conclusion concerns the differences in the stability properties of eastern and western boundary currents. An eastern boundary current supports a greater number of radiating modes over a wider range of meridional wavenumbers. It generates waves with amplitude envelopes that decay slowly with distance from the current. The radiating waves tend to have an asymmetrical horizontal structure—they are much longer in the zonal direction than in the meridional, a consequence of which is that unstable eastern boundary currents, unlike western boundary currents, have the potential to act as a source of zonal jets for the interior of the ocean.

scholarly journals From the western boundary currents to the Pacific Equatorial Undercurrent: Modeled pathways and water mass evolutions

2011 ◽  
Vol 116 (C12) ◽  
Author(s):  
Mélanie Grenier ◽  
Sophie Cravatte ◽  
Bruno Blanke ◽  
Christophe Menkes ◽  
Ariane Koch-Larrouy ◽  
...  
Keyword(s):  
Water Mass ◽  
Western Boundary ◽  
Western Boundary Currents ◽  
Equatorial Undercurrent ◽  
Boundary Currents ◽  
The Pacific

scholarly journals Dynamics of Separating Western Boundary Currents

1999 ◽  
Vol 29 (2) ◽  
pp. 119-144 ◽  
Author(s):  
Ilson C. A. da Silveira ◽  
Glenn R. Flierl ◽  
Wendell S. Brown
Keyword(s):  
Western Boundary ◽  
Western Boundary Currents ◽  
Boundary Currents

Observations of atmosphere-ocean coupling in midlatitude western boundary currents

1996 ◽  
Vol 101 (C3) ◽  
pp. 6295-6312 ◽  
Author(s):  
Kathryn A. Kelly ◽  
Michael J. Caruso ◽  
Sandipa Singh ◽  
Bo Qiu
Keyword(s):  
Western Boundary ◽  
Western Boundary Currents ◽  
Boundary Currents ◽  
Ocean Coupling
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