Behaviour Of Temperature During Wintertime Reversal Of Zonal Wind

Climatologically, the wintertime-evolved stratospheric polar vortex comprises zonal wind, which is westerly. During extreme events like Sudden Stratospheric Warming (SSW), the polar vortex disrupts, showing easterly wind at stratospheric altitudes. Defining extreme events in the stratosphere, like SSW at a definite pressure scale, depends on the region explaining its effects. For instance, the standard definition of SSW is 10 hPa pressure suites primarily for the lower atmosphere. SSW's current definition is unsuitable for the upper atmosphere, especially the ionosphere. So, with this viewpoint, we study the fundamental behaviour of the zonal mean of temperature during the reversal of the zonal mean of zonal wind by using superposed epoch analysis. We use the MERRA2 dataset for this analysis. From MERRA-2, we analyse the zonal mean of temperature and zonal wind from 1980 – 2022 northern hemispheric winters. The analyses are done at 10 hPa, where the standard definition of SSW is defined, and at 1 hPa, 0.5 hPa and 0.1 hPa. Temperature behaviours at different reversal periods are studied at various latitudinal values, starting at 60^oN and ending at 90^oN. With this analysis, a more general picture of the temperature–wind relation can be understood, which will help to understand and define SSW in a much better way for upper atmospheric studies.