The Radiation Condition for Transient Rossby Waves

Abstract

By means of a straightforward application of the Laplace transform, a radiation condition for transient Rossby waves is obtained. The condition is exact for linear problems and permits the numerical simulation of laterally propagating waves in a semi-infinite channel using a finite computational mesh. Linear and non-linear simulations using this condition compare favorably with double-domain integrations for periods of up to 20?40 days. It is shown that the rate of degradation of these simulations depends on both the intensity of the nonlinearities and the scale of motion near the computational boundary. Some possible applications to other problems are also discussed.