Forced Rossby waves in a basin with a meridional barrier and bottom friction

Atherton, J. (2000) Forced Rossby waves in a basin with a meridional barrier and bottom friction. Il nuovo cimento C, 23 C (5). pp. 525-546. ISSN 1826-9885

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The forced, linear, Rossby wave solution for a barotropic fluid in a square basin on a b plane containing a thin, continuous but pierced meridional barrier is examined. The forcing is zonally localized and vorticity is removed through bottom friction. The forcing is applied east of the barrier and is periodic in time. To the north and south of the barrier there are small gaps of equal width d separating the barrier from the basin walls. The value of the stream function on the walls of the basin is zero while the value of the stream function on the barrier, CI , is a function of time, the forcing structure and the forcing frequency. CI is determined by an application of Kelvin’s theorem on a contour about the barrier and its value gives the flux between the two sub-basins that are formed by the barrier. The variance of the stream function is explored as a function of the forcing frequency for different meridional structures of the forcing. We investigate symmetric, antisymmetric, and asymmetric forcings about the mid-latitude of the basin. Peaks in the variance occur at frequencies where the solution is dominated by a full basin or sub-basin mode. It was found that modes which were antisymmetric about the mid-latitude could not propagate past the barrier, while modes which were symmetric about the mid-latitude always had some propagation past the barrier. For the case of eastern sub-basin modes which are symmetric about the mid-latitude this propagation is minute. The sensitivity of the solutions to bottom friction is also discussed. As friction is increased, the peaks in the variance become broader and begin to merge. At sufficiently high values of bottom friction a combination of modes, rather than one single mode, dominates the solution at a peak frequency.

Item Type: Article
Uncontrolled Keywords: Physics of the oceans; Dynamics of the upper ocean; Coriolis effects
Subjects: 500 Scienze naturali e Matematica > 550 Scienze della Terra > 551 Geologia, Idrologia, Meteorologia
Depositing User: Marina Spanti
Date Deposited: 09 Mar 2020 15:59
Last Modified: 09 Mar 2020 15:59

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