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| Titel |
Effects of solar particle events on the hydroxyl airglow layer |
| VerfasserIn |
Holger Winkler, Christian von Savigny, Jan Maik Wissing |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250091395
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| Publikation (Nr.) |
 EGU/EGU2014-5687.pdf |
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| Zusammenfassung |
| The so-called Meinel emissions of vibrationally-rotationally excited hydroxyl molecules
OH* near the mesopause are useful indicators for dynamical and chemical processes in this
region. It is well established that the main source of OH* in the Earth’s mesosphere is the
reaction H + O3 - OH* + O2. During solar particle events (SPEs) energetic protons and
electrons enter the polar atmosphere. The precipitating particles give rise to chemical
perturbations. Of particular interest for the OH chemistry is the ion-chemical conversion
of water molecules into H + OH. Additionally, there is SPE induced ozone loss.
As the formation of OH* is dependent on O3 and H, large SPEs are expected to
affect the hydroxyl airglow layer. Additionally, the changed abundance of atomic
oxygen will impact the quenching of OH*. In addition to the direct initial chemical
composition changes, SPEs are known to affect temperatures, and in turn reaction rates
coefficients.
We present satellite (SABER) observations of OH* emissions during the large SPE in
October/November 2003. Preliminary results indicate significant disturbances of the OH*
airglow layer, and a decrease in the OH* emission altitude. The measurement data are
compared to results of model simulations. SPE effects on OH* are modelled by means of the
UBIC (University of Bremen Ion Chemistry) model using SPE ionisation rates from AIMOS
(Atmospheric Ionization Module Osnabrück). Temperature effects are accounted
for by synthetic temperature disturbances as well as Aura-MLS measurements. |
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