Bremen 2017 – scientific programme

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UP: Fachverband Umweltphysik

UP 21: Atmosphäre - Mesosphäre

UP 21.5: Talk

Friday, March 17, 2017, 14:15–14:30, GW2 B3009

Variability of Hydroxyl nightglow from 2003 to 2011: Impact of the 27-day solar cycle — •Georg Teiser and Christian von Savigny — Universität Greifswald, Deutschland

Airglow observations are a commonly used method to study the Earth atmosphere. OH airglow is a selfluminous phenomenon of the middle atmosphere with a peak in the emission altitude of ~87 km. Particularly the emission of chemically excited OH molecules is used to derive kinetic temperature and is therefore a good opportunity to improve the understanding of middle atmospheric variability. To understand middle atmospheric climate change we need a full understanding of all sources of variability, in particular caused by solar cycle effects. For that reason there is a network of ground-based instruments at locations distributed all over the world to observe the night time OH airglow in the mesopause. In this context the knowledge of the spatial and temporal variability of the nightglow is of importance for the interpretation of ground-based OH temperature measurements. But ground-based measurements of the OH emission altitude are difficult. This gap of altitude information can be filled with satellite measurements.

We used the OH(3-1) band nightglow data set from SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) on Envisat (from August 2002 to April 2012) and applied a Superposed Epoch Analysis to investigate the solar 27-day effects in the emission altitude as well as in the emission rate and derived kinetic temperature. SCIAMACHY measurements cover most years of one solar cycle.