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Titel |
Global anthropogenic aerosol effects on convective clouds in ECHAM5-HAM |
VerfasserIn |
U. Lohmann |
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. 7 ; Nr. 8, no. 7 (2008-04-14), S.2115-2131 |
Datensatznummer |
250006039
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Publikation (Nr.) |
copernicus.org/acp-8-2115-2008.pdf |
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Zusammenfassung |
Aerosols affect the climate system by changing cloud
characteristics in many ways. They act as cloud condensation and ice
nuclei and may have an influence on the hydrological cycle. Here we
investigate aerosol effects on convective clouds by extending the
double-moment cloud microphysics scheme developed for stratiform
clouds, which is coupled to the HAM double-moment aerosol scheme, to
convective clouds in the ECHAM5 general circulation model. This
enables us to investigate whether more, and smaller cloud droplets
suppress the warm rain formation in the lower parts of convective
clouds and thus release more latent heat upon freezing, which would
then result in more vigorous convection and more precipitation. In
ECHAM5, including aerosol effects in large-scale and convective clouds (simulation ECHAM5-conv)
reduces the sensitivity of the liquid water path increase with
increasing aerosol optical depth in better agreement with observations
and large-eddy simulation studies. In simulation ECHAM5-conv with increases in greenhouse
gas and aerosol emissions since pre-industrial times,
the geographical distribution of the changes in precipitation
better matches the observed increase in precipitation than neglecting microphysics in convective clouds. In this
simulation the convective precipitation increases the most suggesting
that the convection has indeed become more vigorous. |
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