Wuppertal 2015 – wissenschaftliches Programm
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EP: Fachverband Extraterrestrische Physik
EP 6: Postersitzung
EP 6.7: Poster
Mittwoch, 11. März 2015, 16:45–18:45, Foyer Ebene G.10
27-day solar rotational effect on auroral mesospheric nighttime OH and O3 observations induced by geomagnetic activity — •Tilo Fytterer1, Michelle Santee2, Miriam Sinnhuber1, and Shuhui Wang2 — 1Institute for Meteorology and Climate Research, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany. — 2Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA.
Precipitating particles (solar protons and electrons) lead to the formation of odd hydrogen ( HOx = H + OH + HO2) in the mesosphere/lower thermosphere region (60 - 110 km) where HOx is locally responsible for catalytic O3 depletion. Measurements performed by the Earth Observing System Microwave Limb Sounder instrument on-board the Aura satellite from 2004 - 2009 (2004 - 2014) were used to investigate the 27-day solar rotational cycle in mesospheric OH (O3) and the physical connection to geomagnetic activity. Data analysis was focused on nighttime measurements at geomagnetic latitudes connected to the outer radiation belts (55° - 75°N/S). The applied superposed epoch analysis reveals a distinct 27-day solar rotational signal in OH and O3 during winter in both the Northern and the Southern Hemisphere at altitudes >70 km. The OH response is positive and in-phase with the respective geomagnetic activity signal, lasting for 1 - 2 days. In contrast the O3 feedback is negative, delayed by one day but lasts up to 4 days afterward. Largest OH (O3) peaks are found at 75 km, exceeding the 95% significance level and reaching variations of +14% (-7%) with respect to their corresponding background.