Early indications of anomalous behaviour in the 2019 spring ozone hole over Antarctica

Abstract

ABSTRACT The level of quasi-stationary planetary wave (QSW) activity in the Antarctic winter stratosphere provides insights into the likely behaviour of the ozone hole in the following spring months. Observation of anomalously large amplitude of the QSW in winter stratospheric temperatures is an indicator that strong disturbances to the polar vortex are likely to occur, and may lead to large reductions in both the area of the Antarctic ozone hole and the overall amount of stratospheric ozone that is depleted. In the sudden stratospheric warming (SSW) preconditions in 2019, the maximum QSW amplitude over Antarctica in August was approximately 12 K, which was only 2 K less than conditions prior to the unprecedented major SSW in 2002. The additional factors disturbing the Antarctic stratosphere in austral winter 2019 were anomalously warm sea surface temperatures in the central tropical Pacific Ocean and the western Indian Ocean, and the descending easterly phase of the Quasi-Biennial Oscillation. Under these preconditions, the Antarctic ozone hole in 2019 had the potential to demonstrate the early disruption and reduced level of the ozone depletion that has been confirmed by the satellite ozone observations. The anomalous ozone hole may also have important regional consequences for weather conditions in the Southern Hemisphere.