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| Titel |
Occurrence of lower cloud albedo in ship tracks |
| VerfasserIn |
Y.-C. Chen, M. W. Christensen, L. Xue, A. Sorooshian, G. L. Stephens, R. M. Rasmussen, J. H. Seinfeld |
| 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 ; 12, no. 17 ; Nr. 12, no. 17 (2012-09-12), S.8223-8235 |
| Datensatznummer |
250011443
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| Publikation (Nr.) |
 copernicus.org/acp-12-8223-2012.pdf |
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| Zusammenfassung |
| The concept of geoengineering by marine cloud brightening is based on seeding
marine stratocumulus clouds with sub-micrometer sea-salt particles to enhance
the cloud droplet number concentration and cloud albedo, thereby producing a
climate cooling effect. The efficacy of this as a strategy for global cooling
rests on the extent to which aerosol-perturbed marine clouds will respond
with increased albedo. Ship tracks, quasi-linear cloud features prevalent in
oceanic regions impacted by ship exhaust, are a well-known manifestation of
the effect of aerosol injection on marine clouds. We present here an analysis
of the albedo responses in ship tracks, based on in situ aircraft
measurements and three years of satellite observations of 589 individual ship
tracks. It is found that the sign (increase or decrease) and magnitude of the
albedo response in ship tracks depends on the mesoscale cloud structure, the
free tropospheric humidity, and cloud top height. In a closed cell structure
(cloud cells ringed by a perimeter of clear air), nearly 30% of ship
tracks exhibited a decreased albedo. Detailed cloud responses must be
accounted for in global studies of the potential efficacy of sea-spray
geoengineering as a means to counteract global warming. |
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