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| Titel |
Influence of Galactic Cosmic Rays on atmospheric composition and dynamics |
| VerfasserIn |
M. Calisto, I. Usoskin, E. Rozanov, T. Peter |
| 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 ; 11, no. 9 ; Nr. 11, no. 9 (2011-05-13), S.4547-4556 |
| Datensatznummer |
250009719
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| Publikation (Nr.) |
 copernicus.org/acp-11-4547-2011.pdf |
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| Zusammenfassung |
| This study investigates the influence of the Galactic Cosmic Rays (GCRs) on
the atmospheric composition, temperature and dynamics by means of the 3-D
Chemistry Climate Model (CCM) SOCOL v2.0. Ionization rates were
parameterized according to CRAC:CRII (Cosmic Ray induced Cascade:
Application for Cosmic Ray Induced Ionization), a detailed state-of-the-art
model describing the effects of GCRs in the entire altitude range of the CCM
from 0–80 km. We find statistically significant effects of GCRs on
tropospheric and stratospheric NOx, HOx, ozone, temperature and
zonal wind, whereas NOx, HOx and ozone are annually averaged and
the temperature and the zonal wind are monthly averaged. In the Southern
Hemisphere, the model suggests the GCR-induced NOx increase to exceed
10 % in the tropopause region (peaking with 20 % at the pole), whereas
HOx is showing a decrease of about 3 % caused by enhanced conversion
into HNO3. As a consequence, ozone is increasing by up to 3 % in the
relatively unpolluted southern troposphere, where its production is
sensitive to additional NOx from GCRs. Conversely, in the northern
polar lower stratosphere, GCRs are found to decrease O3 by up to 3 %,
caused by the additional heterogeneous chlorine activation via
ClONO2 + HCl following GCR-induced production of ClONO2. There is
an apparent GCR-induced acceleration of the zonal wind of up to 5 m s−1 in the
Northern Hemisphere below 40 km in February, and a deceleration at higher
altitudes with peak values of 3 m s−1 around 70 km altitude. The model also
indentifies GCR-induced changes in the surface air, with warming in the
eastern part of Europe and in Russia (up to 2.25 K for March values) and
cooling in Siberia and Greenland (by almost 2 K). We show that these surface
temperature changes develop even when the GCR-induced ionization is taken
into account only above 18 km, suggesting that the stratospherically driven
strengthening of the polar night jet extends all the way down to the Earth's
surface. |
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