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| Titel |
The effects of hygroscopicity on ice nucleation of fossil fuel combustion aerosols in mixed-phase clouds |
| VerfasserIn |
Y. Yun, J. E. Penner, O. Popovicheva |
| 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 ; 13, no. 8 ; Nr. 13, no. 8 (2013-04-26), S.4339-4348 |
| Datensatznummer |
250018611
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| Publikation (Nr.) |
 copernicus.org/acp-13-4339-2013.pdf |
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| Zusammenfassung |
| Fossil fuel black carbon and organic matter (ffBC/OM) are often emitted
together with sulfate, which coats the surface of these particles and
changes their hygroscopicity. Observational studies at cirrus temperatures
(≈−40 °C) show that the hygroscopicity of soot particles can
modulate their ice nucleation ability. Here, we implement a scheme for 3
categories of soot (hydrophobic, hydrophilic and hygroscopic) on the basis
of laboratory data and specify their ability to act as ice nuclei at
mixed-phase temperatures by extrapolating the observations using a published
deposition/condensation/immersion freezing parameterization. The new scheme
results in significant changes to anthropogenic forcing in mixed-phase
clouds. The net forcing in our offline model studies varies from 0.111 to
1.059 W m−2 depending on the ice nucleation capability of hygroscopic
soot particles. The total anthropogenic cloud forcing and whole-sky forcing
with the new scheme are 0.06 W m−2 and −2.45 W m−2, respectively, but
could be more positive (by about 1.17 W m−2) if hygroscopic soot
particles are allowed to nucleate ice particles. The change in liquid water
path dominates the anthropogenic forcing in mixed-phase clouds. |
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