The Influence of the Earth's Rotation on Mountain Wave Drag

Abstract

The two-dimensional flow of a stratified rotating fluid over a ridge is considered using the linear theory model of Queney (1947). A general expression for the wave drag, or alternatively the vertical flux of angular momentum, is derived. As progressively wider mountains are considered, the wave drag decreases and the flow becomes more nearly geostrophic. With typical wind speeds, many mountain ranges, for example, the Alps, Andes and the Scandinavian mountains, have a drag between 0.1 and 0.9 of their f = 0 drag value and thus fall into the mesoscale category where the Coriolis force is important but not dominant.