Collision of anticyclonic, lens-like eddies with a meridional western boundary

The collision of anticyclonic: lens-like eddies with a meridional western boundary is investigated as a function of two independent. nondimensional numbers: beta = beta(0)R/f(0) and epsilon = omega/f(0) where f(0) and beta(0) are the Coriolis parameter and its rate of change with latitude, respectively, both evaluated at the reference latitude: R is the, eddy's radius, and omega is its angular frequency. The numerical experiments show that in all cases there is a southward expulsion of mass proportional to both beta and epsilon, which is estimated during the eddy-boundary interaction. The eddies are invariably deformed with the initial collision, but afterward, they reacquire. a new circular shape. There is a meridional translation of the eddy along the boundary which depends exclusively on the initial ratio r = epsilon/beta. If r > 1, the eddy goes southward. but if r < 1, the eddy goes northward first and then southward. As the eddy loses mass and reacquires a new circular shape: there is a readjustment of beta and epsilon such that beta decreases because its radius becomes smaller and epsilon increases by energy conservation. This implies that the eddies ultimately migrate southward. A formula. derived for the meridional speed of the center of mass of the, eddy is consistent with the numerical results. A physical interpretation shows that after collision a zonal force is exerted on the eddy by the wall which is balanced by a meridional migration. Nonlinearities induce a southward motion: while high beta values could produce, northward motion, depending on the, mass distribution along the wall.