Inertial Oscillations Revisited

Abstract

Coriolis terms proportional to cosφ are omitted in the conventional theory of inertial motions, which predicts horizontal oscillations of frequency f for f-plane geometries in the absence of horizontal and vertical pressure gradients. If this approximation is removed, an oscillation is found within the framework of linear theory that comes rather close to the conventional inertial mode. Motions are quasi-horizontal and the frequency is almost equal to f. However, oscillations vanish at the ground in contrast to the standard theory. Gravity, compressibility, and, in particular, pressure gradient forces are important to this oscillation in addition to Coriolis forces.