The lidar measurements (Tomsk:56.5∘N;85.0∘E) of the optical characteristics of the stratospheric aerosol layer (SAL) in the volcanic activity period 2006–2011 are summarized and analyzed. The background SAL state with minimum aerosol content, observed since 1997 under the conditions of long-term volcanically quiet period, was interrupted in October 2006 by series of explosive eruptions of volcanoes of Pacific Ring of Fire: Rabaul (October 2006, New Guinea); Okmok and Kasatochi (July-August 2008, Aleutian Islands); Redoubt (March-April 2009, Alaska); Sarychev Peak (June 2009, Kuril Islands); Grimsvötn (May 2011, Iceland). A short-term and minor disturbance of the lower stratosphere was also observed in April 2010 after eruption of the Icelandic volcano Eyjafjallajokull. The developed regional empirical model of the vertical distribution of background SAL optical characteristics was used to identify the periods of elevated stratospheric aerosol content after each of the volcanic eruptions. Trends of variations in the total ozone content are also considered.

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The paper analyzes the pattern of the quasi biennial oscillation of the total ozone (TO) and ozone concentrations at separate altitudinal levels in the stratosphere over Arctic territory and Tomsk according to data from the TOMS satellite instruments. The correlation coefficient between TO changes and variations in equa torial zonal wind for the period of 1996-2013 is statistically insignificant. The springtime (March-April) aver age ozone concentrations and zonal wind mostly show the correlation in the interval -0.23-0.26. The mixing ratio time series, composed for separate altitudinal levels over the period 2005-2013, exhibit quasibiennial oscil lation, which takes shape at altitudes of ∼30 km and weakens in overlying regions. The correlation dependence between the ozone mixing ratio and the equatorial zonal wind index is most distinctly manifested in the Western hemisphere and is more complex in the Eastern hemisphere.