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| Titel |
Radiative forcing by contrails |
| VerfasserIn |
R. Meerkötter, U. Schumann, D. R. Doelling, P. Minnis, T. Nakajima, Y. Tsushima |
| 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 ; 17, no. 8 ; Nr. 17, no. 8, S.1080-1094 |
| Datensatznummer |
250013801
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| Publikation (Nr.) |
 copernicus.org/angeo-17-1080-1999.pdf |
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| Zusammenfassung |
A parametric study of the instantaneous
radiative impact of contrails is presented using three different radiative
transfer models for a series of model atmospheres and cloud parameters.
Contrails are treated as geometrically and optically thin plane parallel
homogeneous cirrus layers in a static atmosphere. The ice water content is
varied as a function of ambient temperature. The model atmospheres include
tropical, mid-latitude, and subarctic summer and winter atmospheres. Optically
thin contrails cause a positive net forcing at top of the atmosphere. At the
surface the radiative forcing is negative during daytime. The forcing increases
with the optical depth and the amount of contrail cover. At the top of the
atmosphere, a mean contrail cover of 0.1% with average optical depth of 0.2 to
0.5 causes about 0.01 to 0.03 Wm-2 daily mean instantaneous radiative
forcing. Contrails cool the surface during the day and heat the surface during
the night, and hence reduce the daily temperature amplitude. The net effect
depends strongly on the daily variation of contrail cloud cover. The indirect
radiative forcing due to particle changes in natural cirrus clouds may be of the
same magnitude as the direct one due to additional cover.
Key words. Atmospheric composition and structure
(aerosols and particles) · Meteorology and atmospheric dynamics (climatology ·
radiative processes) |
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