The role of space weather in ozone depletion

Space weather is a set of phenomena in the chain of solar–terrestrial connections observed at a certain point in time at a particular point in space. Usually, space weather connects processes occurring in the ionosphere and atmosphere of the Earth with processes on the Sun and near-Earth space.

Ozone plays a key role in the chain of solar–terrestrial connections and affects climate change, both local and global. Ozone is a gas that determines the temperature and circulation regime of the middle atmosphere, as well as effectively absorbing solar ultraviolet radiation, thereby protecting all living things from dangerous radiation. It is well known that the precipitation of energetic particles leads to the ionization of the Earth's atmosphere, initiating the formation of active chemical compounds that destroy ozone and can affect the composition and dynamics of the atmosphere down to the troposphere.

Here, we evaluate the vulnerability of the ozone layer to space weather processes. Seasonal and latitudinal effects of ozone depletion associated with strong geomagnetic storms and geoeffective solar events are considered separately. We investigate enhancements of mesospheric volume mixing ratios of HO2 and nitric acid HNO3 as well as ozone depletion in the Northern Hemisphere (NH) polar night regions during energetic particle precipitation. We utilize mesospheric observations of HO2, HNO3 and ozone from the Microwave Limb Sounder (MLS/Aura). The analysis of observations made with the MLS/Aura shows that the highest volume mixing ratios of HO2 and HNO3 and also the deepest ozone destruction are observed at a latitudinal range from 60NH to 80NH inside the north polar vortex right after the maximum flux of energetic particle precipitation. .

The work was supported by Saint Petersburg State University under research grant 116234986.