Stratified taylor columns on a beta-plane

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Abstract
The form of quasigeostrophic flow past isolated topography on a beta-plane is obtained for both homogeneous and strongly stratified flows. The stratified flow patterns directly above the bottom boundary are qualitatively similar to the corresponding homogeneous patterns but do not exhibit as marked a deviation from uniform flow away from this boundary. Strong stratification limits the vertical extent of perturbations to western flows. causing them to decay within a distance of order fL/N of the bottom where f is the Coriolis parameter, L the horizontal length scale and N the buoyancy frequency. Perturbations to eastward flows are virtually unattenuated by this height due to the presence of a standing Rossby-wave wake behind the obstacle propagating energy vertically upwards. The minimum height required for an axisymmetric obstacle to cause blocking in a westward current is obtained as a function of the Burger number and the beta parameter. Expressions are given for the force exerted on axisymmetric obstacles in such flows. These consist of a transverse “lift” force independent of the beta effect and stratification, and a wave drag force present only in eastward currents.

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