A climatology of elevated stratopause events in the whole atmosphere community climate model

We also present a climatology of ES events based on NASA's Modern-Era Retrospective Analysis for Research and Applications reanalysis data from 1979 to 2012 and compare it to the model results. WACCM composites of major SSW and ES also show enhanced Eliassen-Palm flux divergences in the upper mesosphere after the stratospheric warming, immediately before the formation of an ES. However, the formation of an ES in WACCM is due primarily to adiabatic heating from gravity wave-driven downwelling, which follows the reestablishment of the eastward jet in the upper stratosphere.

We find nine winters where an ES forms in the absence of any significant planetary wave activity in the upper mesosphere and illustrate one such event.