Ozone Anomaly during Winter-Spring 2019-2020 in the Arctic and over the North of Eurasia Using Satellite (Aura MLS/OMI) Observations

In winter-spring 2019-2020 there was the strongest ozone anomaly in the Arctic in the total history of the observations. It was due to an extraordinarily strong and long-lived polar vortex, entailing unprecedented chemical ozone destruction. Analysis of Aura OMI/MLS data showed that the total ozone content steadily decreased to 230 DU on March 18 at the Alert site, 222 DU on March 18 at Eureka, 229 DU on March 20 at Thule, and 226 DU on March 18 at Resolute. The minimal temperature was 9-10% below normal from December to April in the stratosphere over Tomsk and the Arctic. The ozone concentration decreased to 4% and 6% of the long-term average at an altitude of 20 km on March 27 for Eureka and at an altitude of 19 km on April 16 for Ny-angstrom lesund. This event is within the context of climate changes, leading to cooling of the stratosphere. Until the level of ozone-depleting substances in the stratosphere of the Arctic is above the values expected from implementation of the Montreal Protocol, there will be a danger that these events will recur in the future. The 2020 vortex was exceptionally isolated, which appreciably mitigated its effect in midlatitudes.