Features of the stratospheric wintertime vortex in the Southern hemisphere since the launch of the UARS instrument in 1991 are examined and compared. In particular, indicators of polar vortex strength and planetary wave activity are investigated using UKMO correlative dynamical data for evidence of modulation by the quasi-biennial oscillation. Despite a relatively evenly distributed input of planetary wave amplitude at the tropopause, the amplitude of waves at middle stratospheric levels varied greatly each year, with particular contrast between the greatest activity in the winter of 1992 and the least activity in 1993. These corresponded respectively with a weaker vortex showing early break-up, and a stronger vortex which persisted longer. Data from the HALOE instrument indicates that the early weakening in 1992 led to enhanced advection of chemically perturbed air from the vortex to mid latitudes.