Measurements and modelling of ozone and ozone-related gases near Saint Petersburg, Russia

Ozone anomalous loss in the Northern Hemisphere during winter–spring periods has been increasingly observed in recent decades not only in polar but also in mid-polar regions. Regular monitoring of stratospheric gases involved in ozone-depleting processes is essential for predicting the appearance of ozone mini-holes and the assessment of ozone recovery with the help of numerical models. The location of Saint Petersburg on the border of mid- and high latitudes allows observation of the ozone and ozone-related gas changes under various atmospheric conditions, including polar vortex intrusion. This variability can be estimated with the Bruker IFS 125HR spectrometer (FTIR) located at Saint Petersburg University campus in Peterhof.

A decrease in low stratospheric ozone and stratospheric HNO3 content is observed for the period of 2009-2026, along with an increase in HF due to changes in atmospheric dynamics over the past decade. An observed decrease in CFC-11, CFC-12, ClONO2, HCl, and Cly indicates a decrease in the chlorine-containing gases in the atmosphere.

A comparison of the EMAC and SOCOLv3 numerical modeling results with experimental data showed that ozone variability, including trends, seasonal variations, and rapid winter–spring changes, is described by the models within the measurement uncertainty limits. For HCl, ClONO2, and HNO3, only seasonal variations are simulated adequately; the quantitative discrepancy between the modeled and measurement data exceeds the measurement errors.

This research was funded by Saint Petersburg State University under research project 124032000025-1.