Ozone anomaly during winter-spring 2019-2020 in the Arctic and over the north of Eurasia according to satellite (Aura MLS/OMI) observations
O.E. Bazhenov
V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, Tomsk, Russia
Keywords: total ozone content, ozone concentration, ozone anomaly, Aura satellite
Abstract
In winter-spring 2019-2020 there was the strongest ozone anomaly in the Arctic in the total history of the ozone observations. It was due to 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 until having been 230 DU on March 18 at 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 norm from December to April in the stratosphere over Tomsk and the Arctic. Ozone concentration had been 4% of the long-term mean at altitude of 20 km on March 27 for Eureka and 6% at altitude of 19 km on April 16 for Ny-Ålesund (i.e., about a factor of 30 below). This event is within the context of climate changes leading to cooling of the stratosphere. As far as the level of ozone depleting substances in the stratosphere of the Arctic is above acceptable values, there will be a danger that these events will reoccur in the future. Fortunately, the 2020 vortex was exclusively isolated, which appreciably mitigated its effect on midlatitudes.
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