Würzburg 2018 – scientific programme
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EP: Fachverband Extraterrestrische Physik
EP 1: Near Earth Space
EP 1.4: Talk
Monday, March 19, 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.