Response of Stratospheric Ozone to Sudden Stratospheric Warmings

Response of Stratospheric Ozone to Sudden Stratospheric Warmings Rachael Coons, Department of Atmospheric and Environmental Science, University at Albany SUNY Thomas Birner Department of Atmospheric Science Colorado State University Sudden stratospheric warmings (SSWs), the breakdown and reversal of the stratospheric wintertime westerly circulation around the polar vortex, are the dominant source of variability in the northern hemisphere winter stratosphere. SSWs lead to poleward ozone transport and slowed ozone depletion in the NH winter stratosphere. Here, we characterize SSWs and the associated ozone response using ERA-interim data from 1979-2014 for temperature and wind. Ozone data is used from 2008-2014 (excluding 2009) when assimilation of AURA-MLS ozone greatly improves ERA-interim's ozone product. The warming in SSWs begins in the upper stratosphere about 10 days before the circulation reversal at 10 hPa. These warm anomalies propagate downward through the course of the event. Positive polar-cap ozone anomalies associated with poleward transport are found closer to the event date. Downward transport over the polar cap, which would be expected due to the accelerated Brewer-Dobson circulation during SSWs, is noticeably less pronounced. An outlook into the impact of ozone transport on radiative heating rates during SSWs is provided.