Comparison of the 2011 and 2020 Stratospheric Ozone Events at Arctic and Northern Eurasian Latitudes Using TEMIS and Aura MLS Data

Winters-springs 2019–2020 and 2010–2011 became the periods of the severest ozone events in the Arctic throughout the satellite era. They stemmed from extremely cold and persistent polar stratospheric cloud (PSC) seasons, conducive to record strong chemical ozone destruction. TEMIS observations indicate that the total ozone (TO) column diverged from long-term norm by 45 to 55% in 2020 and by 37 to 44% in 2011 at Arctic sites; and by 27 to 32% in 2020 and by 27 to 36% in 2011 at midlatitudes. Aura MLS profiles showed that the minimum temperature was 8–13% lower than norm over the Arctic in 2020 and 8–12% lower in 2011. The ozone mixing ratios were 4% of the long-term mean at height of 20 km on March 27, 2020 and 25% at height of 21 km on March 20, 2011 for Eureka; and 7% at 19 km on April 19, 2020 and 24% at 20 km on March 20, 2011 for Ny-Ålesund. The divergences in water vapor and ozone mixing ratios, water vapor mixing ratio and temperature, and ozone mixing ratio and temperature show stronger correlations in 2020 than 2011. The correlations weaken equatorward, until becoming almost insignificant at extra-vortex latitudes.