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| Titel |
Possible effect of extreme solar energetic particle event of 20 January 2005 on polar stratospheric aerosols: direct observational evidence |
| VerfasserIn |
I. A. Mironova, I. G. Usoskin, G. A. Kovaltsov, S. V. Petelina |
| 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 ; 12, no. 2 ; Nr. 12, no. 2 (2012-01-17), S.769-778 |
| Datensatznummer |
250010529
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| Publikation (Nr.) |
 copernicus.org/acp-12-769-2012.pdf |
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| Zusammenfassung |
| Energetic cosmic rays are the main source of ionization of the low-middle
atmosphere, leading to associated changes in
atmospheric properties.
Via the hypothetical influence of ionization on aerosol growth and
facilitated formation of clouds, this may be an important indirect
link relating solar variability to climate. This effect is highly
debated, however, since the proposed theoretical mechanisms still
remain illusive and qualitative, and observational evidence is
inconclusive and controversial. Therefore, important questions
regarding the existence and magnitude of the effect, and
particularly the fraction of aerosol particles that can form and
grow, are still open. Here we present empirical evidence of the
possible effect caused by cosmic rays upon polar stratospheric
aerosols, based on a case study of an extreme solar energetic
particle (SEP) event of 20 January 2005. Using aerosol data
obtained over polar regions from different satellites with optical
instruments that were operating during January 2005, such as the
Stratospheric Aerosol and Gas Experiment III (SAGE III), and
Optical Spectrograph and Infrared Imaging System (OSIRIS), we
found a significant simultaneous change in aerosol properties in
both the Southern and Northern Polar regions in temporal
association with the SEP event. We speculate that ionization of
the atmosphere, which was abnormally high in the lower
stratosphere during the extreme SEP event, might have led to
formation of new particles and/or growth of preexisting ultrafine
particles in the polar stratospheric region. However, a detailed
interpretation of the effect is left for subsequent studies. This
is the first time high vertical resolution measurements have been
used to discuss possible production of
stratospheric aerosols under the influence of cosmic ray induced ionization.
The observed effect is marginally detectable for the analyzed severe SEP
event and can be undetectable for the majority of weak-moderate events. The
present interpretation serves as a conservative upper limit of solar
energetic particle effect upon polar stratospheric aerosols. |
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