A comparative study of the major sudden stratospheric warmings in the Arctic winters 2003/2004-2009/2010

Jayanarayanan Kuttippurath (1) , G. Nikulin (2)

1 STRATO - LATMOS
2 SMHI - Swedish Meteorological and Hydrological Institute

We present an analysis of the major sudden stratospheric warmings (SSWs) in the Arctic winters 2003/04-2009/10. There were 6 major SSWs (major warmings [MWs]) in 6 out of the 7 winters, in which the MWs of 2003/04, 2005/06, and 2008/09 were in January and those of 2006/07, 2007/08, and 2009/10 were in February. Although the winter 2009/10 was relatively cold from mid-December to mid-January, strong wave 1 activity led to a MW in early February, for which the largest momentum flux among the winters was estimated at 60° N/10 hPa, about 450 m2 s−2. The strongest MW, however, was observed in 2008/09 and the weakest in 2006/07. The MW in 2008/09 was triggered by intense wave 2 activity and was a vortex split event. In contrast, strong wave 1 activity led to the MWs of other winters and were vortex displacement events. Large amounts of Eliassen-Palm (EP) and wave 1/2 EP fluxes (about 2-4 ×105 kg s−2) are estimated shortly before the MWs at 100 hPa averaged over 45-75° N in all winters, suggesting profound tropospheric forcing for the MWs. We observe an increase in the occurrence of MWs (~1.1 MWs/winter) in recent years (1998/99-2009/10), as there were 13 MWs in the 12 Arctic winters, although the long-term average (1957/58-2009/10) of the frequency stays around its historical value (~0.7 MWs/winter), consistent with the findings of previous studies. An analysis of the chemical ozone loss in the past 17 Arctic winters (1993/94-2009/10) suggests that the loss is inversely proportional to the intensity and timing of MWs in each winter, where early (December-January) MWs lead to minimal ozone loss. Therefore, this high frequency of MWs in recent Arctic winters has significant implications for stratospheric ozone trends in the northern hemisphere.

Domaines: Physique Atmosphérique et Océanique [physics.ao-ph]

Jayanarayanan Kuttippurath, G. Nikulin. A comparative study of the major sudden stratospheric warmings in the Arctic winters 2003/2004-2009/2010. Atmospheric Chemistry and Physics, 2012, 12 (17), pp.8115-8129. ⟨10.5194/acp-12-8115-2012⟩. ⟨hal-00678622⟩