A study of the effect of cloud droplets on the diffusional growth rate of ice particles

NESVIT E. CASTELLANO; ELDO E. AVILA; CLIVE P. R. SAUNDERS

Bologna - Italia

Conferencia; 14th International Conference on Clouds and Precipitation; 2004

Title: A study of the effect of cloud droplets on the diffusional growth rate of ice particles Abstract: The growth of ice particles in a supercooled water cloud due to the ifferences between water and ice saturation vapour densities (Bergeron-Findeisen mechanism) is the usual process that occurs in clouds, however this process has not been extensively studied so far. Instead, the usual treatment is based on the classical electrostatic analogy theory of diffusional growth (Mason, 1971; Pruppacher and Klett, 1978) and involves the diffusion of water molecules from a vapour source at infinity towards the ice crystal. The electrostatic analogy theory does not take into account the presence of water droplets surrounding the growing ice particle. However, it is reasonable to assume that their presence could enhance the mass transfer and consequently the growth rate of the ice particle. A numerical study of the growth rate of ice particles in an array of water droplets is presented here. The model uses the method of electrostatic image charges to determine the vapour density field in which an ice particle grows.