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UP: Fachverband Umweltphysik

UP 14: Atmosphäre - Spurengase, Aerosole und Labormessungen

UP 14.3: Hauptvortrag

Donnerstag, 28. Februar 2013, 11:00–11:30, HS 5

The chemistry of sprites and related plasma processes in the middle atmosphere — •Holger Winkler — Institut für Umweltphysik, Universität Bremen

Transient luminous events (TLEs) are large scale electric discharges occurring between active thunderstorms and the ionosphere. The most famous TLEs are the so-called sprites in the mesosphere, but there are other types of TLEs such as halos, elves, (blue) jets, (blue) starters, and gigantic jets. The plasma processes in TLEs give rise to chemical disturbances; in particular they lead to a production of reactive nitrogen and hydrogen radicals as well as other species affecting ozone. We have developed a plasma chemistry model in order to study the impact of TLEs in detail. Here we give an overview of TLEs and present some recent model results. For the first time, we were able to study the ion chemistry of a daytime sprite streamer in a consistent way. The chemical impact of a daytime sprite is found to be significantly larger than that of a nighttime sprite, especially in the lower mesosphere. The model was also applied to blue jet events in the stratosphere for which there are no detailed studies so far. One issue in TLE modeling is the impact on longer and larger scales. In order to simulate the mixing of streamer gas with the ambient atmosphere, a chemistry and diffusion model has been coupled to the plasma chemistry model. This allows providing chemical TLE impacts for global scale atmospheric chemistry and transport models.