Using the WACCM chemistry-climate model, L.A. Holt and co-authors investigate the effect of major sudden stratospheric warmings (SSWs) and elevated-stratopause events (ES) on the transport of NOx produced by energetic particle precipitation (EPP) during the Northern Hemisphere winter. The model simulations indicate large increases in NOx following SSW and ES events, which are attributed to an increase in the descending branch of the residual circulation (w*) following an event. Interestingly, the earlier and event occurs in winter, the more NOx descends into the stratosphere. The full abstract can be found here.