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| Titel |
Do supersonic aircraft avoid contrails? |
| VerfasserIn |
A. Stenke, V. Grewe, S. Pechtl |
| 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 ; 8, no. 4 ; Nr. 8, no. 4 (2008-02-25), S.955-967 |
| Datensatznummer |
250005676
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| Publikation (Nr.) |
 copernicus.org/acp-8-955-2008.pdf |
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| Zusammenfassung |
| The impact of a potential future fleet of supersonic aircraft on
contrail coverage and contrail radiative forcing is investigated by
means of simulations with the general circulation model
ECHAM4.L39(DLR) including a contrail parameterization. The model
simulations consider air traffic inventories of a subsonic fleet and
of a combined fleet of sub- and supersonic aircraft for the years
2025 and 2050, respectively. In case of the combined fleet, part of
the subsonic fleet is replaced by supersonic aircraft. The combined
air traffic scenario reveals a reduction in contrail cover at
subsonic cruise levels (10 to 12 km) in the northern extratropics,
especially over the North Atlantic and North Pacific. At supersonic
flight levels (18 to 20 km), contrail formation is mainly
restricted to tropical regions. Only in winter is the northern
extratropical stratosphere above the 100 hPa level cold enough for
the formation of contrails. Total contrail coverage is only
marginally affected by the shift in flight altitude. The model
simulations indicate a global annual mean contrail cover of 0.372%
for the subsonic and 0.366% for the combined fleet in 2050. The
simulated contrail radiative forcing is most closely correlated to
the total contrail cover, although contrails in the tropical lower
stratosphere are found to be optically thinner than contrails in the
extratropical upper troposphere. The global annual mean contrail
radiative forcing in 2050 (2025) amounts to 24.7 mW m−2
(9.4 mW m−2) for the subsonic fleet and 24.2 mW m−2
(9.3 mW m−2) for the combined fleet. A reduction of the
supersonic cruise speed from Mach 2.0 to Mach 1.6 leads to a
downward shift in contrail cover, but does not affect global mean
total contrail cover and contrail radiative forcing. Hence the
partial substitution of subsonic air traffic leads to a shift of
contrail occurrence from mid to low latitudes, but the resulting
change in contrail-induced climate impact is almost negligible. |
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