St Petersburg University scientists prove that magnetic storms destroy up to a quarter of the earth’s ozone layer in the mesosphere
Physicists at St Petersburg University, other Russian universities, and Physikalisch-Meteorologisches Observatorium Davos/World Radiation Center (PMOD/WRC) have proved that magnetic storms destroy up to a quarter of the Earth’s polar mesosphere in one day. The recorded destruction is at an altitude of about 75 km. The results were obtained in the Laboratory for the Research of the Ozone Layer and the Upper Atmosphere at St Petersburg University. It is part of the mega-grant programme of the Ministry of Science and Higher Education of the Russian Federation.
The destruction of the Earth’s ozone layer is usually associated with precipitation of energetic particles, i.e. protons, electrons, and alpha particles. These particles penetrate into the Earth’s atmosphere to a height of 100 km and below from the magnetosphere. The magnetosphere is the region around the Earth, and its physical properties are determined by the planet’s magnetic field and its interaction with flux of cosmic ray and energetic solar particles.
The research findings are published in the scientific journal Atmosphere.
Precipitation of energetic particles is also associated with auroras and atmospheric ionisation caused by these particles in a wide range of altitudes. The additional ion pairs form radicals that are involved in catalytic reactions that destroy ozone.
Scientists at the Laboratory for the Research of the Ozone Layer and the Upper Atmosphere at St Petersburg University have developed an online course "Space Weather: Environmental Impact Assessment". It covers such key topics as: the Sun and solar activity; the Earth’s atmosphere and the main atmospheric processes; and impact of energetic particles and electromagnetic radiation on the Earth’s atmosphere and the ozone layer.
Today, scientists around the world pay great attention to the study of the state of the Earth’s ozone layer and changes in climatic conditions on the planet. The study of the ozone layer is underpinned by the study of the influence of natural and anthropogenic factors from the surface of the planet to near-Earth outer space.
‘We found that during geomagnetic disturbances, i.e. changes in the Earth’s magnetic field, usually manifested during magnetospheric storms, the concentration of radicals increases in the polar atmosphere. This leads to the destruction of ozone at the heights of the mesosphere during the day. The maximum recorded destruction was 14–25% at an altitude of about 75 km. In other words, magnetospheric storms can destroy up to a quarter of the ozone layer’, explained Irina Mironova, Head of the section "Magnetosphere and the influence of energetic particles on the atmosphere" at the Laboratory for the Research of the Ozone Layer and the Upper Atmosphere at St Petersburg University.
Selection of energetic electron precipitation events and ozone modelling were carried out by members of the scientific team of the Laboratory for the Research of the Ozone Layer and Upper Atmosphere of St. Petersburg University in the framework of the interdisciplinary project of the Russian Science Foundation (project № 22-62-00048).
Expanding the range of heights of the models was performed under project № 20-05-00450 of the Russian Foundation for Basic Research. Studies of the change in the electron density during precipitation of energetic electrons were part of project № 20-55-12020 of the Russian Foundation for Basic Research.
The scientists obtained detailed data on the number of particles in the atmosphere by measuring X-rays via bremsstrahlung caused by energetic electrons precipitating into the atmosphere. Observations were carried out over Apatity in the Murmansk Region in different periods of time. To calculate the ionization rates of the atmosphere, the researchers used a calculation scheme in which the spectra and fluxes of precipitating electrons are reconstructed based on the measured X-ray radiation. To estimate the destruction of the ozone layer, the scientists developed a mathematical model to study the transport of solar and infrared radiation, photochemical processes, ion chemistry, and turbulent vertical transport of gaseous impurities.
For a more complete and detailed study, St Petersburg University scientists have created a model to calculate the temperature and concentration of 43 neutral gases, free electrons and 57 ions involved in more than 300 different reactions: for example, reactions involving nitrogen and hydrogen catalytic cycles of ozone destruction.
The results obtained by St Petersburg University scientists can be used to more accurately predict the future ozone layer and the Earth’s climate as well as to analyse radio wave propagation.