Polar Stratosphere Dynamics During Early Sudden Stratospheric Warmings

Sudden stratospheric warming (SSW) significantly impacts the weather in the troposphere and the dynamics of the upper atmosphere. The definition of SSWs and their classifications have been formulated for a long time. However, early (in November – the first half of December) SSWs are understudied. In this work, the effect of early SSWs on a stratospheric polar vortex is studied based on JRA-55 and MERRA-2 reanalysis data. Early SSWs are determined in two ways, in terms of the zonal average temperature and the zonal wind component with and without the climatological norms of the component. Polar vortex response to SSW is represented by the geopotential altitude field. The variations in the surface temperature and surface pressure during displacement and splitting of a stratospheric polar vortex during an early SSW are also analyzed based on sounding data at polar stations in different continents.