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UP: Fachverband Umweltphysik

UP 4: Poster Session

UP 4.8: Poster

Tuesday, March 8, 2016, 16:00–17:30, Foyer H41

Sensitivity of equatorial atomic oxygen in the MLT region to the quasi-11-year and quasi-27-day solar cycles — •Olexandr Lednyts’kyy and Christian von Savigny — Ernst-Moritz-Arndt-University of Greifswald, Greifswald, Germany

The influence of solar activity on atomic oxygen (O) formation plays a critical role in the MLT (Mesosphere/Lower Thermosphere) region. We retrieved O concentration ([O]) profiles and studied atmospheric chemistry in the MLT region on a near-global basis with help of SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) observations of the nightglow green line emission. We estimated the sensitivity of equatorial [O] to the 11-year and 27-day solar cycle forcing represented by such proxy indicators of solar activity as MgII index and Lyman-α with help of the wavelet, cross-correlation and superposed epoch analysis methods. We applied ordinary least squares bisector fitting on MgII index and F10.7 radio flux, which is measured in solar flux units (sfu), to convert the [O] sensitivity values in sfu and finally in percent changes. The same procedure was performed in the case of Lyman-α. Our results of the sensitivity analysis correspond well to the 11-year solar cycle response of O volume mixing ratios found in simulations performed with the WACCM3 (Whole Atmosphere Community Climate Model, v. 3) and the HAMMONIA (3D Hamburg Model of the Neutral and Ionized Atmosphere) model. We identified an 11-year solar cycle variation, quasi-biennial and annual/semi-annual oscillations as well as signatures of the 27-day cycle of solar activity as presented in the MLT O layer.