Characteristics of Changes in the Ozone Content in the Upper Stratosphere over Moscow during the Cold Half-Years of 2014–2015 and 2015–2016

The results of ground-based microwave measurements of the stratospheric ozone profiles over Moscow during the cold half-years of 2014–2015 and 2015–2016 are presented. The causes of the observed changes in the ozone in the upper stratosphere are considered. Increased planetary wave activity, strong temperature decreases in the beginning of winter, and decreased temperatures from January to March were detected during the winter of 2014–2015. The polar vortex was long-lived but not deep; the cold air of the vortex was over Moscow in February–March. This led to a strong negative correlation of the measured ozone content with the temperature. The highest ozone content at the 2-mb level was observed in mid-March. Conversely, an intense polar vortex formed in November–December 2015 under lower planetary wave activity; it was completely destroyed by the major final warming in the beginning of March 2016. The ozone variations in the upper stratosphere over Moscow in December 2015 and January 2016 were related to the alternation of air masses of the vortex and regions outside the vortex. Higher temperatures (as compared to those in the beginning of 2015) led to a decreased ozone content in the beginning of 2016. The interannual difference in the ozone content in the first half of March exceeded 40% of the monthly mean value.