Decadal Variations in the Winter Beaufort High and the Stratospheric Polar Vortex

Abstract

AbstractWe show that a weakened Beaufort High in late winter is becoming more common since the late 1980s, and this weakening is related to decadal changes in Northern Hemisphere ozone depletion. During this time, the stratospheric polar vortex has experienced a decadal northeastward displacement. Such displacement is associated with the variability of the East Asia‐eastern North America dipole. A positive Asia‐eastern North America dipole leads to zonal asymmetry in the ozone depletion with maximum loss over eastern Eurasia. Positive feedback with the zonally asymmetric ozone loss contributes to increased occurrence of the northeastward displacement of the stratospheric polar vortex. The northeastward displaced polar vortex enhances baroclinicity over the Eurasian Arctic and causes an increase in the frequency and intensity of cyclones and a decrease in anticyclones over the Eurasian Arctic. Concomitantly, the Beaufort High tends to have weakened.