Disturbance of the stratosphere over Tomsk in winter 2017-2018 using lidar and satellite (Aura MLS) observations

Abstract

Lidar observations of aerosol and ozone at Siberian Lidar Station (SLS) of Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences in Tomsk (26° 29’ N; 85° 3’ E) showed the presence of stratospheric aerosol layers over Tomsk during winter 2017-2018, signs of descending air masses, and deficit of ozone. Aura OMI/MLS observations indicated that in December-January 2017/2018 the northern Eurasia had been under the influence of Arctic air masses from the Eastern Hemisphere with low total ozone (TO) content and NO₂ content in the stratosphere, and low temperature in the stratosphere. Analysis of back trajectories and integrated (over MLS profile) TO showed that, due to dynamic disturbance of the Arctic stratosphere in December 2017, cold air masses with excessive reactive chlorine (in view of NO₂ deficit) were exported from within the Arctic circle to the stratosphere over Tomsk. Seemingly, in the Tomsk stratosphere, after being exposed to solar radiation and to the excessive reactive chlorine (in view of NO₂ deficit), and, staying chemically isolated, they evolved into chemically disturbed state, similar in ozone destruction rate to the conditions of the springtime Arctic stratosphere.