Heidelberg 2022 – wissenschaftliches Programm
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EP: Fachverband Extraterrestrische Physik
EP 5: Near Earth Space
EP 5.6: Vortrag
Dienstag, 22. März 2022, 18:00–18:15, EP-H1
Impact of chlorine ion chemistry on the ozone loss during very large solar proton events — •Monali Borthakur1, Thomas Reddmann1, Miriam Sinnhuber1, Gabrielle Stiller1, Thomas Von Clarmann1, and Ilya Usoskin2 — 1Karlsruhe Institute of Technology, Karlsruhe, Germany — 2University of Oulu, Oulu, Finland
Strong eruptions on the Sun can accelerate charged particles, mostly protons, to high energies, causing solar proton events (SPEs). Such energetic particles can precipitate upon the Earth's atmosphere, mostly in polar regions because of the geomagnetic shielding. SPE induced chlorine activation and its impact on stratospheric ozone in the polar northern atmosphere has been investigated using a 1D stacked-box model, of atmospheric ion and neutral composition, EXOTIC. Two SPEs were used as test fields: the Halloween SPE late October 2003 and an extreme event of 775 AD, which was derived from historical records of cosmogenic nuclides. We used observations of chlorine species and ozone from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) on ENVISAT to evaluate model results for the Halloween event. Model experiments were carried out with full ion chemistry as well as with a common parameterisation scheme considering the formation of HOx and NOx. Additional ozone destruction due to the chlorine catalytic cycles was observed as well in the upper stratosphere and lower mesosphere. For the parameterised model runs, ozone depletion was observed to be the largest for full parameterisation.