High and Equatorial Mesospheric Dynamical Response to the Minor Stratospheric Warming of 2014/15: Comparison with major SSW Events 2005/06 and 2008/09

Abstract

We present the high and equatorial mesospheric dynamical response to the minor stratospheric warming that occurred in 2014/15 and compared it with the major stratospheric warming events of 2005/06 and 2008/09. Meteor radar observations over Esrange (67.88^oN, 21.07^o E), Mohe (52.97^oN, 122.53^oE) and Kototabang (0.20^oS, 100.32^oE) have been extensively utilized in addition to ERA 5 Reanalysis datasets. Possessing the unique feature of a vortex displacement and split, the minor warming of 2014/15 was observed on 27 December 2014 followed by four subsequent temperature peaks. During the 2014/15 minor SSW, the tropical stratospheric temperature decreased, causing upwelling similar to the major SSW events 2005/06 and 2008/09. The equatorial mesospheric zonal wind in 2014/15 displayed maximum westward wind with a delay of ~ 19 days after the vortex disruption comparable to the major SSW events. Whereas, over Esrange and Mohe, the westward wind maxima occurred about the vortex disruption during all the warming events. During the minor SSW 2014/15, the ~ 16-day planetary wave is observed to be relatively stronger in the equatorial mesosphere than the high latitude mesosphere. The Eliassen Palm flux diagnostics revealed the intrusion of planetary wave energy from high latitudes to the tropical band, suggesting meridional and equatorward propagation of the planetary waves.