Comparison Of Northern And Southern Hemispheric SSW Using Reanalysis Data

Abstract

Sudden Stratospheric Warming (SSW) is an extreme dynamical event observed in the middle atmosphere. During this event, there will be changes in circulation behaviour in the middle atmosphere followed by a sudden warming in the polar stratosphere. The warming scenario is preceded by the polar vortex disruption due to the non-linear interaction of extra-tropical planetary waves from the troposphere with the mean flow. SSW affects both the upper and lower atmosphere, irrespective of latitude. It is known that warming events are more frequent in the northern hemisphere than in the southern hemisphere. The study investigates the evolution of warming events in both the northern and southern hemispheres. We use the reanalysis data to compare the 2013 - 2014 northern hemisphere and 2002 southern hemisphere SSW. To understand the forcing and responses in both hemispheres, we conducted meteorological and statistical analyses of SSW using temperature, zonal wind, meridional wind, and geopotential height. The factors that modulate the intensity of warming events in both hemispheres have been discussed in detail.