ON THE INFLUENCE OF TOPOGRAPHY AND STRATIFICATION ON PLANETARY-WAVES IN THE OCEAN (2-LAYER MODEL)

A theory of Rossby waves in a two-layer ocean over a cylindrical bottom relief is developed. The theory is valid in a wide range of governing parameters (horizontal scale and height of bottom bumps, horizontal wavelengths and some others). Three wave modes are found whose structure and frequencies strongly depend on the characteristic relative height of bottom bumps. The observable attenuation of mesoscale motion over strongly uneven bottom is explained in the framework of a simple linear model. It is shown that the stratification prevents the main thermocline from penetration of motions with horizontal scale smaller than the Rossby deformation radius. The results of the asymptotic theory are confirmed by investigation of sinusoidal bottom relief case using the theory of differential equations with periodic coefficients.