Technical Note: Intermittent reduction of the stratospheric ozone over Northern Europe caused by a storm in Atlantic Ocean

• Main Authors: Sofiev, Mikhail, Kouznetsov, Rostislav, Hänninen, Risto, Sofieva, Viktoria F.
• Format: Text
• Language: English
• Published: 2019
• Subjects: Greenland; Siberia
• Online Access: https://doi.org/10.5194/acp-2019-356; https://www.atmos-chem-phys-discuss.net/acp-2019-356/

A three-day episode of anomalously low ozone concentrations in the stratosphere over Northern Europe occurred on 3–5 November 2018. A reduction of the total ozone column down to ~ 200–210 Dobson Units was predicted by the global forecasts of System for Integrated modeLling of Atmospheric coMposition (SILAM) driven by the weather forecast of Integrated Forecasting System (IFS) of European Centre for Medium-Range Weather Forecasting (ECMWF). The reduction down to 210–215 DU was subsequently observed by the satellite instruments, such as Ozone Monitoring Instrument (OMI) and Ozone Mapping Profile Suite (OMPS). The episode was caused by intrusion of the tropospheric air, which was initially uplifted by a storm in Northern Atlantic, south-east of Greenland. Subsequent transport towards the east and further uplift over Scandinavian ridge of this humid and low-ozone air brought it to ~ 25 km altitude causing ~ 30 % reduction of the ozone layer thickness over Northern Europe. The low-ozone air was further transported eastwards and diluted over Siberia, so that the ozone concentrations restored a few days later. High accuracy of the episode prediction 5 days in advance by the IFS-SILAM modelling tandem illustrates the model capabilities of short-term forecasting of the stratospheric composition, including such rare events.