The 2006 major sudden warming. Top: time-height cross-section of temperatures during the major SSW in late January 2006. Note the descent and disappearance of the stratopause at the peak of the warming and its subsequent reappearance and descent from the mesosphere. Bottom: the time variation of the zonal-mean zonal wind at 10 hPa and 60 N. The blue line shows the wind during the stratwarm, while the red line depicts the climatalogical seasonal cycle. Adapted from Figure one of Yamazaki et al. (2012).