Planetary Wave Interactions in the Antarctic Stratosphere

Variations in planetary wave 1 amplitudes on timescales of the order of 10 days have often been noted in the Antarctic stratosphere. These episodes of wave 1 growth are associated with accelerated erosion and warming of the polar vortex and hence can act to limit springtime ozone depletion.

In this study, these wave 1 events are shown to be related to episodes of wave 1 - wave 2 interaction, where wave 1 undergoes periodic amplification when the phase ridges of the two waves are spatially coincident. These events may also be viewed from the synoptic perspective as vortex interactions, often between a quasi-stationary anticyclone and a series of travelling anticyclonic features.

In this talk, we focus on one particular sequence of such events and view the evolution of the flow from both the linear zonal-mean (wave - wave interaction) and synoptic (vortex interaction) perspectives.