Topographic waves in rectangular basins

Abstract

The channel model of Stocker & Hutter (1986, 1987) is used to construct topographic wave solutions in a rectangular basin on the f-plane with variable but symmetric bathymetry. We show that in a narrow period band three types of eigenmodes can be discerned which exhibit local, midscale and global structure, respectively. Wave motion can be trapped either at the long sides of the elongated basin (channel mode) or at the ends of it (bay mode) or alternatively, a basinwide phase rotation is observed (Ball mode). The new bay modes are explained as resonances of topographic wave reflection in a semi-infinite channel. The influence of the variation of the aspect ratio of the rectangle and the topography parameter on the wave periods is also investigated.