For longer times it is assumed that aerosol particles influence the convective activity of clouds, especially of deep convective clouds. By application of numerical simulations it should be elucidated if this hypothesis is reliable. In proofing this hypothesis numerical simulations have been performed at IMK using the operational NWP model COSMO of the German Weather Service for situations relevant to the effect of convective clouds. In the COSMO model a newly developed parameterization of cloud microphysics (two moment method, Seifert and Beheng, 2006 a,b) has been applied. The mentioned tow moment scheme has thus extended by introduction of a further hydrometeor class, namely hail (Blahak, 2008).

The following situations have been investigated:

• The formation and development of a strong hailstorm happening on June, 28 2006 near the town of Villingen-Schwenningen (in the southern Black Forest, Germany) causing large economic losses by about 280 billion Euro (Noppel, Blahak, …, 2010)

• Influencing precipitation formation in the Eastern Mediterranean for augmenting precipitation at land in contrast to the usual case as precipitation release over sea (Noppel, Pokrovski, … 2010)

• Effects of increased CCN- and IN-concentrations of surface precipitation amounts during three summer periods It turned out that depending on each specific situation a more or less significant influence of aerosol particles on precipitation occurred. However, a stringent link of cause and effect solely by aerosol particles could not be verified. ( Seifert, A., Köhler, ...)

It turned out that depending on each specific situation a more or less significant influence of aerosol particles on precipitation occurred. However, a stringent link of cause and effect solely by aerosol particles could not be verified.

Literature:

1. Noppel, H., Blahak, U., Seifert, A., Beheng, K.D. ,2009:
Simulations of a hailstorm and the impact of CCN using an advanced two-moment cloud microphysical scheme
Atmos. Res., 96, 286-301, Abstract 

2. Noppel, H., Pokrovsky, A., Lynn, B., Khain, A.P., Beheng, K.D. ,2010:
A spatial shift of precipitation from the sea to the land caused by introducing submicron soluble aerosols: Numerical modeling
J. Geophys. Res., 115 (D18212), 1-17, Abstract 

3. Seifert, A., Köhler, C., Beheng, K.D. ,2012:
Aerosol-cloud-precipitation effects over Germany as simulated by a convective-scale numerical weather prediction model
Atmos. Chem. Phys., 12, 709-725, Abstract 

4.Seifert, A., Beheng, K.D. ,2006:
A two-moment cloud microphysics parameterization for mixed-phase clouds. Part I: Model description
Meteorol. Atmos. Phys., 92, 45-66, Abstract 

 5. Seifert, A., Beheng, K.D. ,2006:
A two-moment cloud microphysics parameterization for mixed-phase clouds. Part II: Deep convective storms
Meteorol. Atmos. Phys., 92, 67-82, Abstract 

6. Blahak, U. , 2008:
Towards a Better Representation of High Density Ice Particles in a State-of-the-Art Two-Moment Bulk Microphysical Scheme
15 th International Conference on Clouds and Precipitation, Cancun Mexico, 07.07.-11.07.2008