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EP: Fachverband Extraterrestrische Physik

EP 1: Near Earth Space

EP 1.4: Vortrag

Montag, 19. März 2018, 17:30–17:45, BSZ - Pabel HS

Impact of geomagnetic activity on thermospheric composition and circulation, and their coupling to the middle and upper atmosphere — •Sabine Barthlott¹, Miriam Sinnhuber¹, Thomas Reddmann¹, Stefan Versick¹, Holger Nieder², and Alexey Vlasov² — ¹Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany — ²formerly KIT

External forcing by high-speed solar wind streams and solar coronal mass ejections (so-called geomagnetic forcing) incfluences composition and circulation of the lower thermosphere. Essential processes are photoionisation, particle ionisation and joule heating. Hereby produced changes in the thermosphere also effect other atmospheric layers. Enhanced nitrogen monoxide (NO) due to auroral ionisation subsides and influences atmospheric layers below (e. g. ozone layer). Gravity waves, excited in the lower thermosphere by e. g. geomagnetic storms, can propagate upwards and influence the environment of low-Earth orbit satellites.

To correctly reproduce this coupling with models, it is important, to describe these processes in the lower thermosphere as precisely as possible. We use and further develop the coupled chemistry-climate-model EMAC (used in an extended version up to ∼220 km) is further developed and processes mentioned above (e. g. photoionisation) are implemented. Using the example of winter 2008/2009, results of the further developed model will be compared with standard simulations and observations.