Ссылка для участия: https://telemost.yandex.ru/j/32732741115250
На семинаре выступит с докладом Dr. Pavle Arsenovic (BOKU, Vienna, Austria)
Abstract:
Energetic particles, closely tied to solar activity, play a significant role in influencing the chemical composition of Earth’s upper atmosphere. By ionizing neutral air molecules, they generate reactive nitrogen and hydrogen species (NOx and HOx), which catalytically deplete ozone. These ozone changes can alter atmospheric temperatures and dynamics, with cascading effects that may extend to surface climate. Furthermore, reductions in ozone increase ultraviolet (UV) radiation at the Earth’s surface, posing risks to living organisms, including heightened skin cancer rates and damage to ecosystems.
Energetic particles are classified into five categories based on their sources and energies: galactic cosmic rays (GCR), solar energetic protons (SEP), low-energy electrons (LEE, from auroral and plasmasheet regions), and middle- and high-energy electrons (MEE and HEE, from the Van Allen radiation belts). While SEP and radiation belt electrons can penetrate the mesosphere and stratosphere, the effects of lower-energy electrons are confined to altitudes above 90 km. The Earth’s magnetic field shields most of these particles, restricting their influence to polar regions; however, during geomagnetic excursions or reversals, when the magnetic field is significantly weaker, their impacts could become globally significant.
In this seminar, I will present our findings on the distinct and combined impacts of LEE and MEE on NOx and HOx production and the resulting ozone depletion. I will also discuss the isolated effects of MEE on atmospheric chemistry, dynamical changes, and surface temperatures. Regarding SEP, I will highlight the atmospheric chemical effects of an extreme SEP event under present geomagnetic field conditions and explore its amplified impact during periods of geomagnetic field absence. These results offer insights into the evolutionary implications of past extreme SEP events and emphasize the potentially underestimated risks they pose to human health and ecosystems.