Energetic particle precipitation (EPP) has important implications on atmospheric chemistry. The principal mechanism is the formation of odd nitrogen and hydrogen radicals, both involved in catalytic ozone destruction, via a cascade of dissociation, ionization, and recombination processes. Sporadically, solar eruptions generate intense particle fluxes of very high energy with the potential to penetrate deep into the polar atmosphere. During such solar proton events (SPEs), which are more frequent near solar maximum, stratospheric and mesospheric chemistry can be dramatically altered. On the other hand, magnetospheric electrons precipitate continuously into the atmosphere and generate large amounts of nitric oxide in the polar upper mesosphere and lower thermosphere. This occurs throughout the solar cycle, however, with a maximum intensity approximately 2 years after solar maximum when the solar wind speeds up. In the absence of sunlight during polar winter, large amounts of EPPgenerated odd nitrogen can be transported down to the stratosphere by the meridional circulation without being photo-chemically destroyed. This mechanism is often called EPP indirect effect. EPP hence represents an important solar-terrestrial coupling mechanism that is directly linked to solar variability. The influence of EPP on climate through stratospheric chemical and dynamical processes is barely understood, but is likely to extend beyond the polar middle atmosphere. This talk aims at giving an overview on recent advances in the investigation of EPP effects on the atmosphere obtained from both observational data and model studies. An important focus will be given on the ongoing activities in the framework of the High Energy Particle Precipitation in the Atmosphere (HEPPA) model vs. data inter-comparison initiative.

Diese Veranstaltung ist Teil der Reihe Karlsruher Meteorologisches Kolloquium

Referent/in
Dr. Bernd Funke

CSIC, Granada, Spanien
Instituto de Astrofisica de Andalucia

Veranstalter
Institut für Meteorologie und Klimaforschung - Atmosphärische Umweltforschung (IMK-IFU)
Karlsruher Institut für Technologie (KIT)
Kreuzeckbahnstraße 19
82467 Garmisch-Partenkirchen
E-Mail: hape schmid ∂does-not-exist.imk kit edu

Zielgruppe
Wissenschaftliche Mitarbeitende