Circulation Structures in the Polar Stratosphere of the Northern Hemisphere during the 2019–2021 Winters

This work is devoted to the study of the upper stratosphere circulation features in quiet and disturbed periods. A comparative analysis of blocking properties of the polar stratospheric vortex during December and January 2019–2021 is carried out. ERA5 reanalysis data and Aura-MLS satellite data are used. To determine the inner boundary of the polar vortex, the method of launching test particles in a three-dimensional field of wind speed values is used, forcing the particles to form closed circulation structures. The focus of this work is to determine the differences in the dynamics of the stratospheric vortex under quiet and disturbed conditions. It is shown that, during the development of the main phase of a sudden stratospheric warming similar to the one that occurred in January 2021, the circulation structure of the vortex is destroyed. This vortex disruption contributes to significant “meridional” mixing of the polar stratosphere. Estimates of average vertical velocity of movement of the test particles are made.