BAROTROPIC FLOW OVER FINITE ISOLATED TOPOGRAPHY - STEADY SOLUTIONS ONTHE BETA-PLANE AND THE INITIAL-VALUE PROBLEM

Solutions for inviscid rotating flow over a right circular cylinder of finite height are studied, and comparisons are made to quasi-geostrop hic solutions. To study the combined effects of finite topography and the variation of the Coriolis parameter with latitude a steady invisci d model is used. The analytical solution consists of one part which is similar to the quasi-geostrophic solution that is driven by the poten tial vorticity anomaly over the topography, and another, similar to th e solution of potential flow around a cylinder, that is driven by the matching conditions on the edge of the topography. When the characteri stic Rossby wave speed is much larger than the background flow velocit y, the transport over the topography is enhanced as the streamlines fo llow lines of constant background potential vorticity. For eastward fl ow, the Rossby wave drag can be very much larger than that predicted b y quasi-geostrophic theory. The combined effects of finite height topo graphy and time-dependence are studied in the inviscid initial value p roblem on the f-plane using the method of contour dynamics. The method is modified to handle finite topography. When the topography takes up most of the layer depth, a stable oscillation exists with all of the fluid which originates over the topography rotating around the topogra phy. When the Rossby number is order one, a steady trapped vortex solu tion similar to the one described by Johnson (1978) may be reached.