On the role of the eruption of the Merapi volcano in an anomalous total ozone decrease over Tomsk in April 2011

In April 2011, at Northern Hemisphere midlatitudes, a long-term anomalous decrease in the total ozone content was recorded over a number of regions, attributed to echoes of a large-scale Arctic ozone anomaly, observed in March. We showed that stratospheric ozone destruction over Tomsk during that period was caused by an eruption of Indonesian volcano Merapi in November, 2010. The NOAA HYSPLIT model was used to analyze air mass transport in the lower stratosphere starting from coordinates of volcanic emission from the date of eruption until late April. It was found that air masses, containing volcanic aerosol, came to the Northern Hemisphere midlatitudes in late March, 2011, in agreement with high aerosol content recorded in the stratosphere over Tomsk during that period. Based on analysis of temperature and ozone anomalies in the stratosphere over Tomsk, these anomalies were shown to be due to the presence of volcanic soot in aerosol composition.