• Corpus ID: 201686126

TOWARDS A BETTER REPRESENTATION OF HIGH DENSITY ICE PARTICLES IN A STATE-OFTHE-ART TWO-MOMENT BULK MICROPHYSICAL SCHEME

@inproceedings{Blahak2008TOWARDSAB,
  title={TOWARDS A BETTER REPRESENTATION OF HIGH DENSITY ICE PARTICLES IN A STATE-OFTHE-ART TWO-MOMENT BULK MICROPHYSICAL SCHEME},
  author={Ulrich Blahak},
  year={2008}
}

• U. Blahak
• Published 2008
• Environmental Science, Physics

One of the upcoming topics in cloud microphysics is to investigate the influence of increased air pollution by anthropogenic aerosols on the evolution of convective clouds and formation of hail in midlatitude storms. In this context, it is of importance that the cloud microphysical scheme is able to predict the evolution of hail with a certain degree of confidence. Hail particles may influence the microphysicaldynamical feedback and the simulated precipitation efficiency due to their ability for efficient collision and riming growth and high sedimentation velocity. Originally, the 2-moment bulk microphysical scheme by Seifert and Beheng (2006) with the modifications given in Seifert et al. (2006), henceforth called ”bulk scheme”, comprised the 5 hydrometeor categories cloud water, rain water, cloud ice, snow and graupel. It predicts the first 2 moments of the underlying particle size distribution with respect to particle mass, namely the numberand mass density, for each of the hydrometeor classes. In principal, this enables a more realistic simulation of most cloud microphysical processes (e.g., collision/coalescence, accretion, sedimentation, evaporation) compared to conventional 1-moment schemes. In contrast to other 2-moment schemes, a new detailed parameterization of warm rain processes (autoconversion, accretion, selfcollection) is applied as well as a very careful treatment of all other collision processes (solid-solid and liquidsolid). E.g., collision processes between ice species take into account a variation of the fallspeed for particles of a given size. Moreover, the scheme is able to take into account different aerosol regimes (high-CCN versus low-CCN conditions). Recently, the Seifert-Beheng-scheme (referred to as twomoment scheme in the following) has been revised with respect to a better representation of high density ice particles like hail. These revisions are motivated (sections 2 and 3) and described (section 5) in the following.