BAROCLINIC WAVES OF THE POLAR-NIGHT VORTEX

Abstract

The behavior of the polar-night westerlies of the stratosphere is discussed, and their probable vertical extent is examined from rocket sounding evidence. It is shown that travelling wave-perturbations, typically of zonal wave number near four, affect the vortex and have phase-velocities similar to those of the tropospheric westerlies. The amplification and movement of one of these systems is shown by means of a detailed case-study of vorticity and mass perturbations. The writers conclude that the behavior of these systems supports the view that they are baroclinic waves converting available potential energy to kinetic energy at stratospheric levels.