OROGRAPHY IN A CONTOUR DYNAMICS MODEL OF LARGE-SCALE ATMOSPHERIC FLOW

The influence of orography on the structure of stationary planetary Ro ssby waves is studied in the context of a contour dynamics model of th e large-scale atmospheric flow. Orography of infinitesimal and finite amplitude is studied using analytical and numerical techniques. Three different types of orography are considered: idealized orography in th e form of a global wave, idealized orography in the form of a local ta ble mountain, and the earth's orography. The study confirms the import ance of resonances, both in the infinitesimal orography and in the fin ite orography cases. With finite orography the stationary waves organi ze themselves into a one-dimensional set of solutions, which due to th e resonances, is piecewise connected. It is pointed out that these sta tionary waves could be relevant for atmospheric regimes.