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					AEROSOL-CLOUD RESEARCH


Atmospheric physics and chemistry group
IMAU, Utrecht University
Cloud dynamical, microphysical and optical properties
are influenced by aerosol number concentration and
chemical composition

Focus IMAU on indirect effects

Indirect effects concern:
• albedo change
• cloud microphysics (precipitation formation)
• cloud dynamics (entrainment, turbulence)
• cloud processing
Aerosol-cloud parcel model

• Köhler microphysics
• collision/coalescence
• aerosol/ dropsize distribution: 200 bins
• precipitation water: 50 bins
• sulfur chemistry from SO2, H2O2, O3, HNO3, NH3

aerosol:
 200 size bins (0.02-2.0 µm)
 inorganics/OC/BC/dust/seasalt
 internal/external mixture
Cloud parcel model - sensitivity study


                                         precip
Base case:
Remote continental conditions              cloud water
Inorganic aerosol,
         50% soluble (NH4HSO4)
Updraft speed 0.5 m/s
End simulation at 1.6 g/m3



                                           total LWC
CDNC
precipitation
formation
Cloud chemical processing of aerosol




                after




       before
Models employed at IMAU
Coupled aerosol-cloud microphysics/chemistry model
3D LES model with detailed aerosol/cloud microphysics
Global aerosol-climate model (3D or SCM)


Research foci
Detailed cloud dynamics, microphysics and chemistry
Interactions and feedbacks between processes
Development of cloud parameterizations for GCMs
Radiative transfer in clouds
Simulation of specific cloud events

				
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posted:4/30/2013
language:English
pages:8