1. Numerical investigations on melting of large ice particles and shedding as well as meteorological applications B. Weigand, N. Roth, ITLR, Univ. Stuttgart K.D. Beheng, U. Blahak, IMK, Univ. Karlsruhe/FZK K‘he Melting of ice particle Liquid water film on ice particle Instability of liquid water film by drag / cappilar waves Shedding of drops Drops join pre-existing dsd foster precip formation (coag / freezing), may induce downdrafts due to latent heat consumption by melting and due to evaporation of small drops

2. Previous (and only) lab work, Rasmussen et al, 1984 No validation up to now No quantification of size distribution of shedded drops

3. Preliminary work at ITLR, Stuttgart Evaporating oscillating drop (diam. 2.1 mm), grid box 10x10x10 cm**3 FS3D: Solution of incompr. NS-eq and temp.eq (DNS, VOF), liquid surface by PLIC

4. Research goals (for 6 years) Numerical simulation of melting and shedding Quantification of size distribution of shedded drops (as, e.g., function of ice particle size, flow field (Reynolds-number) and its temperature Validation of previous lab experiments Theoretical formulation of shedding in the spectral-kinetic equations Implementation in a sophisticated cloud model operating with spectral equations (HUCM = Hebrew University Cloud Model, Prof Khain ) Parameterization of the shedding effect for use in an existing two- moment microphysics module (Seifert and Beheng, 2006; COSMO-DE) Investigation of the shedding effect by numerical simulations of strong convective (hail-bearing) clouds Internal collaboration IPA, Uni Mainz

5. Benefits NWP prediction, cloud-resolving detailed modelling International cooperation Hebrew Univ. Jerusalem Israel NCAR (Rasmussen, Heymsfield, Thompson) Ressources / Costs ITLR : Personnel: 1 full time PhD, 1 student assistent Lab: tbd Travel: 2500 / 3 a, publication costs IMK: Personnel: 1/2 time PhD, 1 student assistent Travel : 2500/ 3 a, publication costs