Atmos. Chem. Phys. Discuss., 13, 32327-32351, 2013
www.atmos-chem-phys-discuss.net/13/32327/2013/
doi:10.5194/acpd-13-32327-2013
© Author(s) 2013. This work is distributed
under the Creative Commons Attribution 3.0 License.
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This discussion paper has been under review for the journal Atmospheric Chemistry and Physics (ACP). Please refer to the corresponding final paper in ACP.
Local impact of solar variation on NO2 in the lower mesosphere and upper stratosphere from 2007–2011
F. Friederich1, M. Sinnhuber1, B. Funke2, T. von Clarmann1, and J. Orphal1
1Karlsruhe Institute of Technology, Institute for Meteorology and Climate Research, Karlsruhe, Germany
2Instituto de Astrof\' isica de Andaluc\' ia, CSIC, Granada, Spain

Abstract. MIPAS/ENVISAT data of nighttime NO2 volume mixing ratios (VMR) from 2007 until 2011 between 40 km and 62 km altitude are compared with the geomagnetic Ap index and solar Lyman α radiation. The local impact of variations in geomagnetic activity and solar radiation on the VMR of NO2 in the lower mesosphere and upper stratosphere in the Northern Hemisphere is investigated by means of superposed epoch analysis. Observations show a clear 27 day period of the NO2 VMR. This is positively correlated to the geomagnetic Ap index at 60–70° N geomagnetic latitude but also partially correlated to the solar Lyman α radiation. However, the dependency of NO2 VMR on geomagnetic activity can be distinguished from the impact of solar radiation. This indicates a direct response of NOx (NO + NO2) to geomagnetic activity, probably due to precipitating particles. The response is detected in the range between 46 km and 52 km altitude. The NO2 VMR epoch maxima due to geomagnetic activity is altitude-dependent and can reach up to 0.4 ppb, leading to mean production rates of 0.029 ppb (Ap d)−1. This is the first study showing the local impact of electron precipitation on trace gases at that altitudes in the spring/summer/autumn hemisphere.

Citation: Friederich, F., Sinnhuber, M., Funke, B., von Clarmann, T., and Orphal, J.: Local impact of solar variation on NO2 in the lower mesosphere and upper stratosphere from 2007–2011, Atmos. Chem. Phys. Discuss., 13, 32327-32351, doi:10.5194/acpd-13-32327-2013, 2013.
 
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