Density-Driven General Circulation in a Closed Basin Using a Two-Lavel ModelSource: Journal of Physical Oceanography:;1986:;Volume( 016 ):;issue: 005::page 902Author:Ikeda, Motoyoshi
DOI: 10.1175/1520-0485(1986)016<0902:DDGCIA>2.0.CO;2Publisher: American Meteorological Society
Abstract: A rectangular-basin ocean, driven by buoyancy and density fluxes in its northern and southern portions, is studied using a two-level model. Only baroclinic motion is induced under the conditions of 1) no wind, 2) neither interfacial nor bottom stresses, 3) momentum equations, and 4) flat bottom. The relaxation problem, initiated by a north-south density difference, is studied first. It is found that a zonal geostrophic flow induces upwelling and downwelling near the eastern and western boundaries, resulting in alongshore flows characterized by frictional internal Kelvin waves. These flows are compensated by upwelling and downwelling near the northern and southern boundaries, reducing the meridional density gradient. The relaxation time scale is proportional to the area of the basin and inversely proportional to the square of an internal gravity wave speed. The second problem is a steady state forced by continuous fluxes. It has qualitatively the same flow patterns as the relaxation problem. To establish a steady state with finite amplitude circulation, both relatively small vertical diffusion, and buoyancy and density fluxes to the lower level are required. Horizontal diffusion tends to spread density anomalies offshore from the eastern and western boundaries and to diminish intensified, narrow boundary currents. Upwelling and/or downwelling in a wide central area, balancing meridional velocity with planetary beta effect in the vorticity equation, plays a minor role in maintaining the density field, except in a low latitude region.
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contributor author | Ikeda, Motoyoshi | |
date accessioned | 2017-06-09T14:47:53Z | |
date available | 2017-06-09T14:47:53Z | |
date copyright | 1986/05/01 | |
date issued | 1986 | |
identifier issn | 0022-3670 | |
identifier other | ams-27003.pdf | |
identifier uri | http://onlinelibrary.yabesh.ir/handle/yetl/4163961 | |
description abstract | A rectangular-basin ocean, driven by buoyancy and density fluxes in its northern and southern portions, is studied using a two-level model. Only baroclinic motion is induced under the conditions of 1) no wind, 2) neither interfacial nor bottom stresses, 3) momentum equations, and 4) flat bottom. The relaxation problem, initiated by a north-south density difference, is studied first. It is found that a zonal geostrophic flow induces upwelling and downwelling near the eastern and western boundaries, resulting in alongshore flows characterized by frictional internal Kelvin waves. These flows are compensated by upwelling and downwelling near the northern and southern boundaries, reducing the meridional density gradient. The relaxation time scale is proportional to the area of the basin and inversely proportional to the square of an internal gravity wave speed. The second problem is a steady state forced by continuous fluxes. It has qualitatively the same flow patterns as the relaxation problem. To establish a steady state with finite amplitude circulation, both relatively small vertical diffusion, and buoyancy and density fluxes to the lower level are required. Horizontal diffusion tends to spread density anomalies offshore from the eastern and western boundaries and to diminish intensified, narrow boundary currents. Upwelling and/or downwelling in a wide central area, balancing meridional velocity with planetary beta effect in the vorticity equation, plays a minor role in maintaining the density field, except in a low latitude region. | |
publisher | American Meteorological Society | |
title | Density-Driven General Circulation in a Closed Basin Using a Two-Lavel Model | |
type | Journal Paper | |
journal volume | 16 | |
journal issue | 5 | |
journal title | Journal of Physical Oceanography | |
identifier doi | 10.1175/1520-0485(1986)016<0902:DDGCIA>2.0.CO;2 | |
journal fristpage | 902 | |
journal lastpage | 918 | |
tree | Journal of Physical Oceanography:;1986:;Volume( 016 ):;issue: 005 | |
contenttype | Fulltext |