THE EFFECT OF ISOLATED TOPOGRAPHY ON WEST FLOW

With the Fourier-expanding expression of isolated topography,the forcing of isolated topography is studied in this paper.In the initial condition of steady uniform west flow in β-plan channel model,the approximate solution of quasi-geostrophic potential vorticity equation is obtained.The results indicate that a series of steady topographic standing and transient waves can be produced by the forcing of isolated topography.The wave can move eastward or westward according to the wave scales.The most slowly Rossby wave is the strongest wave.So is the standing wave corresponding to the wave number.The main action of topography is to produce these strong waves.It is suggested that action of topography is one of the main causes to produce low frequency oscillation and long-range steady weather.