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| Titel |
On the determination of the global cloud feedback from satellite measurements |
| VerfasserIn |
T. Masters |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
2190-4979
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| Digitales Dokument |
URL |
| Erschienen |
In: Earth System Dynamics ; 3, no. 2 ; Nr. 3, no. 2 (2012-08-23), S.97-107 |
| Datensatznummer |
250001002
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| Publikation (Nr.) |
 copernicus.org/esd-3-97-2012.pdf |
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| Zusammenfassung |
| A detailed analysis is presented in order to determine the sensitivity of
the estimated short-term cloud feedback to choices of temperature datasets,
sources of top-of-atmosphere (TOA) clear-sky radiative flux data, and
temporal averaging. It is shown that the results of a previous analysis,
which suggested a likely positive value for the short-term cloud feedback,
depended upon combining all-sky radiative fluxes from NASA's Clouds and
Earth's Radiant Energy System (CERES) with reanalysis clear-sky forecast
fluxes when determining the cloud radiative forcing (CRF). These results are
contradicted when ΔCRF is derived using both all-sky and clear-sky
measurements from CERES over the same period. The differences between the
radiative flux data sources are thus explored, along with the potential
problems in each. The largest discrepancy is found when including the first
two years (2000–2002), and the diagnosed cloud feedback from each method is
sensitive to the time period over which the regressions are run. Overall,
there is little correlation between the changes in the ΔCRF and
surface temperatures on these timescales, suggesting that the net effect of
clouds varies during this time period quite apart from global temperature
changes. Given the large uncertainties generated from this method, the
limited data over this period are insufficient to rule out either the
positive feedback present in most climate models or a strong negative cloud
feedback. |
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