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Titel |
Sensitivity studies of different aerosol indirect effects in mixed-phase clouds |
VerfasserIn |
U. Lohmann, C. Hoose |
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 ; 9, no. 22 ; Nr. 9, no. 22 (2009-11-26), S.8917-8934 |
Datensatznummer |
250007768
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Publikation (Nr.) |
copernicus.org/acp-9-8917-2009.pdf |
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Zusammenfassung |
Aerosols affect the climate system by changing
cloud characteristics. Using the global climate model ECHAM5-HAM, we
investigate different aerosol effects on mixed-phase clouds: The
glaciation effect, which refers to a more frequent glaciation due to
anthropogenic aerosols, versus the de-activation effect, which
suggests that ice nuclei become less effective because of an
anthropogenic sulfate coating. The glaciation effect can partly
offset the indirect aerosol effect on warm clouds and thus causes the
total anthropogenic aerosol effect to be smaller. It is investigated
by varying the parameterization for the Bergeron-Findeisen process and
the threshold coating thickness of sulfate (SO4-crit), which is
required to convert an externally mixed aerosol particle into an
internally mixed particle. Differences in the net radiation at the
top-of-the-atmosphere due to anthropogenic aerosols between the
different sensitivity studies amount up to 0.5 W m−2. This
suggests that the investigated mixed-phase processes have a major
effect on the total anthropogenic aerosol effect. |
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