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| Titel |
The 11-year solar cycle in current reanalyses: a (non)linear attribution study of the middle atmosphere |
| VerfasserIn |
A. Kuchar, P. Šácha, J. Miksovsky, P. Pisoft |
| 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 ; 15, no. 12 ; Nr. 15, no. 12 (2015-06-24), S.6879-6895 |
| Datensatznummer |
250119847
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| Publikation (Nr.) |
 copernicus.org/acp-15-6879-2015.pdf |
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| Zusammenfassung |
| This study focusses on the variability of temperature, ozone and circulation
characteristics in the stratosphere and lower mesosphere with regard to the
influence of the 11-year solar cycle. It is based on attribution analysis
using multiple nonlinear techniques (support vector regression, neural
networks) besides the multiple linear regression approach. The analysis was
applied to several current reanalysis data sets for the 1979–2013 period,
including MERRA, ERA-Interim and JRA-55, with the aim to compare how these
types of data resolve especially the double-peaked solar response in
temperature and ozone variables and the consequent changes induced by these
anomalies. Equatorial temperature signals in the tropical stratosphere were
found to be in qualitative agreement with previous attribution studies,
although the agreement with observational results was incomplete, especially
for JRA-55. The analysis also pointed to the solar signal in the ozone data
sets (i.e. MERRA and ERA-Interim) not being consistent with the observed
double-peaked ozone anomaly extracted from satellite measurements. The
results obtained by linear regression were confirmed by the nonlinear
approach through all data sets, suggesting that linear regression is a
relevant tool to sufficiently resolve the solar signal in the middle
atmosphere. The seasonal evolution of the solar response was also discussed
in terms of dynamical causalities in the winter hemispheres. The hypothetical
mechanism of a weaker Brewer–Dobson circulation at solar maxima was reviewed
together with a discussion of polar vortex behaviour. |
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