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| Titel |
Evidence of impact of aviation on cirrus cloud formation |
| VerfasserIn |
C. S. Zerefos, K. Eleftheratos, D. S. Balis, P. Zanis, G. Tselioudis, C. Meleti |
| 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 ; 3, no. 5 ; Nr. 3, no. 5 (2003-10-06), S.1633-1644 |
| Datensatznummer |
250001267
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| Publikation (Nr.) |
 copernicus.org/acp-3-1633-2003.pdf |
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| Zusammenfassung |
| This work examines changes in cirrus cloud cover
(CCC) in possible association with aviation activities at congested air corridors. The analysis is based on the latest version of the
International Satellite Cloud Climatology Project D2 data set and covers the period
1984-1998. Over the studied areas, the effect of large-scale modes of natural climate variability
such as ENSO, QBO and NAO as well as the possible influence of the tropopause variability,
were first removed from the cloud data set in order to calculate long-term changes of observed
cirrus cloudiness. The results show increasing trends in (CCC) between 1984 and 1998 over
the high air traffic corridors of North America, North Atlantic and Europe. Of these upward
trends, only in the summertime over the North Atlantic and only in the wintertime over North
America are statistically significant (exceeding +2.0% per decade). Over adjacent locations
with low air traffic, the calculated trends are statistically insignificant and in most cases
negative both during winter and summer in the regions studied. These negative trends, over
low air traffic regions, are consistent with the observed large scale negative trends seen in
(CCC) over most of the northern middle latitudes and over the tropics. Moreover, further
investigation of vertical velocities over high and low air traffic regions provide evidence that
the trends of opposite signs in (CCC) over these regions, do not seem to be caused by
different trends in dynamics. It is also shown that the longitudinal distribution of decadal
changes in (CCC) along the latitude belt centered at the North Atlantic air corridor, parallels
the spatial distribution of fuel consumption from highflying air traffic, providing an
independent test of possible impact of aviation on contrail cirrus formation. The correlation
between the fuel consumption and the longitudinal variability of (CCC) is significant (+0.7)
over the middle latitudes but not over the tropics. This could be explained by the fact that over
the tropics the variability of (CCC) is dominated by dynamics while at middle latitudes
microphysics explain most of its variability. Results from this study are compared with other
studies and for different periods of records and it appears that there exists general agreement
as to the evidence of a possible aviation effect on high cloud positive trends over regions with
congested air traffic. |
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