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| Titel |
Is thermospheric long-term cooling due to CO2 or O3? |
| VerfasserIn |
P. L. Walsh, W. L. Oliver |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 29, no. 10 ; Nr. 29, no. 10 (2011-10-11), S.1779-1782 |
| Datensatznummer |
250017105
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| Publikation (Nr.) |
 copernicus.org/angeo-29-1779-2011.pdf |
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| Zusammenfassung |
| While greenhouse gases trap heat emanating from the Earth and
thereby heat the surface atmosphere, they act as emitters in the high
atmosphere and cool the air there.
In 1989 Roble and Dickinson (1989) estimated the cooling that
would occur in the thermosphere (250–500 km altitude) due to
a doubling of greenhouse gas densities.
Ever since, long-term data bases have been scoured for evidence
of this thermospheric "global cooling."
Here we show evidence that the thermosphere did indeed cool over
the period 1966–1987, but the data suggest that the cooling
accelerated at a "breakpoint year" around 1979 to a rate far larger
than may be attributed to greenhouse cooling.
This 1979 breakpoint year appears to coincide with a breakpoint
year in ozone (O3) column density.
Further, the cooling was confined largely to the daytime
thermosphere while the nighttime showed only a small trend.
These results suggest, first, that the greenhouse cooling of the
thermosphere may well not be detectable with current data sets and,
second, that the long-term cooling that is clearly seen may be due
largely to O3 depletion. |
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