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| Titel |
Local impact of solar variation on NO2 in the lower mesosphere and upper stratosphere from 2007 to 2012 |
| VerfasserIn |
F. Friederich, M. Sinnhuber, B. Funke, T. Clarmann, J. Orphal |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 14, no. 8 ; Nr. 14, no. 8 (2014-04-23), S.4055-4064 |
| Datensatznummer |
250118633
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| Publikation (Nr.) |
 copernicus.org/acp-14-4055-2014.pdf |
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| Zusammenfassung |
| MIPAS/ENVISAT data of nighttime
NO2 volume mixing ratios (VMR) from 2007 until 2012 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 in the Northern Hemisphere show a
clear 27-day period of the NO2 VMR. This is positively correlated with the
geomagnetic Ap index at 60–70° N geomagnetic latitude but also
partially correlated with 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. Observations in the Southern
Hemisphere do not have the same significance due to a worse sampling of
geomagnetic storm occurances. Variabilities due to solar variation occur at
the same altitudes at 60–70° S geomagnetic latitude but cannot be
analyzed as in the Northern Hemisphere. This is the first study showing the
direct impact of electron precipitation on NOx at those altitudes in
the spring/summer/autumn hemisphere. |
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