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| Titel |
Impact of aerosols on the hydrologic cycle in the regional climate model CCLM |
| VerfasserIn |
E. Zubler, U. Lohmann, D. Lüthi, A. Muhlbauer, C. Schär |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250020126
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| Zusammenfassung |
| Since aerosols serve as cloud condensation and ice nuclei they influence the microphysical
properties of clouds and precipitation. Increasing the aerosol number in a cloud leads to a
deceleration of hydrometeor growth and may also cause significant changes in ice formation.
On the regional scale, aerosols may therefore alter precipitation patterns, possibly leading to a
spin-down of the hydrologic cycle. Hence, the representation of complex cloud and aerosol
microphysics is crucial to narrow down current uncertainties in regional climate
modelling.
In this study, the regional climate model CCLM (version 4.0) was coupled to an aerosol
microphysics module and a 2-moment bulk cloud scheme. The aerosol module accounts for
the life cycle (emission, chemical evolution through condensation of soluble material onto the
particles and water uptake, in- and below-cloud scavenging, sedimentation and dry
deposition) of major aerosol species such as sulfate, seasalt, soil dust, black and organic
carbon. The 2-moment cloud microphysics scheme allows for the prognostic representation
of both mass and number concentrations for 5 different types of cloud and precipitation
particles.
An overview of the physical parameterizations and first results with the newly
coupled version of CCLM4.0 are shown. Sensitivity studies will be conducted for a
time span of 1960-2000 driven by ERA-40 reanalysis, applying aerosol boundary
data from the global atmospheric circulation model ECHAM5-HAM. It is shown
that the new model version produces physically consistent results. Aerosol and
cloud optical properties as well as number and mass concentrations are simulated
reasonably. |
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