Antarctic Ozone Enhancement During the 2019 Sudden Stratospheric Warming Event

We analyze the 2019 sudden stratospheric warming event that occurred in the Southern Hemisphere through its impact on the Antarctic ozone. Using temperature, ozone, and nitric acid data from the Infrared Atmospheric Sounding Interferometer (IASI), our results show that the average increase in stratospheric temperature reached a maximum of 34.4 degrees on 20 September in the [60-90]degrees S latitude range when compared to the past 3 years. Dynamical parameters suggest a locally reversed and weakened zonal winds and a shift in the location of the polar jet vortex. This led to air masses mixing, to a reduced polar stratospheric clouds formation detected at a ground station, and as such to lower ozone and nitric acid depletion. 2019 total ozone columns for the months of September, October, and November were on average higher by 29%, 28%, and 26%, respectively, when compared to the 11-year average of the same months. Plain Language Summary In August and September 2019 exceptional meteorology led to a sudden increase in temperatures at altitudes between 20 and 30 km above the ground over Antarctica. This is a rare and very important event since it has direct effects on the ozone hole size and distribution. In this work, we investigate this event, using satellite and ground-based station data. We document the warming, its starting date (end of August), and how long it lasted (around 3 weeks). This warming helped in stopping the formation of high altitude icy clouds that usually trap ozone depleting species. When springtime starts (September/October), these depleting species are usually released and ozone destruction starts. This year however, and due to the warming, very little ozone destruction took place, leading to high ozone columns (small ozone hole) over Antarctica.