Influence of increased activity of planetary waves on the Arctic polar vortex dynamics in winter 2018/2019

Abstract

The Arctic stratospheric polar vortex usually forms in autumn, reaches its peak intensity in mid-winter and decays from late winter to spring. In most cases, the polar vortex breakdown occurs as a result of the penetration of vertically propagating planetary waves into the stratosphere and is accompanied by the occurrence of sudden stratospheric warmings. In the winter of 2018/2019, the vortex breakdown occurred in late December after increased wave activity for more than 10 days in the first half of winter. In this work, we examined the unusual dynamics of the Arctic polar vortex in the lower stratosphere in the winter of 2018/2019 using a new method based on the vortex delineation.