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| Titel |
Linear trends in cloud top height from passive observations in the oxygen A-band |
| VerfasserIn |
L. Lelli, A. A. Kokhanovsky, V. V. Rozanov, M. Vountas, J. P. Burrows |
| 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 ; 14, no. 11 ; Nr. 14, no. 11 (2014-06-06), S.5679-5692 |
| Datensatznummer |
250118780
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| Publikation (Nr.) |
 copernicus.org/acp-14-5679-2014.pdf |
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| Zusammenfassung |
| Measurements by the hyperspectral spectrometers GOME, SCIAMACHY and GOME-2
are used to determine the rate of linear change (and trends) in cloud top
height (CTH) in the period between June 1996 and May 2012. The retrievals are
obtained from Top-Of-Atmosphere (TOA) backscattered solar light in the oxygen
A-band using the Semi-Analytical CloUd Retrieval Algorithm SACURA. The
physical framework relies on the asymptotic equations of radiative transfer,
valid for optically thick clouds. Using linear least-squares techniques, a
global trend of −1.78 ± 2.14 m yr−1 in deseasonalized CTH has
been found, in the latitude belt within ±60°, with diverging
tendencies over land (+0.27 ± 3.2 m yr−1) and ocean
(−2.51 ± 2.8 m yr−1). The El Niño–Southern Oscillation
(ENSO), strongly coupled to CTH, forces clouds to lower altitudes. The global
ENSO-corrected trend in CTH amounts to −0.49 ± 2.22 m yr−1. At
a global scale, no explicit regional pattern of statistically significant
trends (at 95% confidence level, estimated with bootstrap technique) have
been found, which would be representative of typical natural synoptical
features. One exception is North Africa, which exhibits the strongest upward
trend in CTH sustained by an increasing trend in water vapour. |
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