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| Titel |
Cosmic rays linked to rapid mid-latitude cloud changes |
| VerfasserIn |
B. A. Laken, D. R. Kniveton, M. R. Frogley |
| 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 ; 10, no. 22 ; Nr. 10, no. 22 (2010-11-24), S.10941-10948 |
| Datensatznummer |
250008905
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| Publikation (Nr.) |
 copernicus.org/acp-10-10941-2010.pdf |
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| Zusammenfassung |
| The effect of the Galactic Cosmic Ray (GCR) flux on Earth's climate is highly
uncertain. Using a novel sampling approach based around observing periods of
significant cloud changes, a statistically robust relationship is identified
between short-term GCR flux changes and the most rapid mid-latitude
(60°–30° N/S) cloud decreases operating over daily
timescales; this signal is verified in surface level air temperature (SLAT)
reanalysis data. A General Circulation Model (GCM) experiment is used to test
the causal relationship of the observed cloud changes to the detected SLAT
anomalies. Results indicate that the anomalous cloud changes were responsible
for producing the observed SLAT changes, implying that if there is a causal
relationship between significant decreases in the rate of GCR flux
(~0.79 GU, where GU denotes a change of 1% of the
11-year solar cycle amplitude in four days) and decreases in cloud cover
(~1.9 CU, where CU denotes a change of 1% cloud
cover in four days), an increase in SLAT (~0.05 KU, where
KU denotes a temperature change of 1 K in four days) can be
expected. The influence of GCRs is clearly distinguishable from changes in
solar irradiance and the interplanetary magnetic field. However, the results
of the GCM experiment are found to be somewhat limited by the ability of the
model to successfully reproduce observed cloud cover. These results provide
perhaps the most compelling evidence presented thus far of a GCR-climate
relationship. From this analysis we conclude that a GCR-climate relationship
is governed by both short-term GCR changes and internal atmospheric precursor
conditions. |
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