The effect of cloud conditions on charge transfer in thunderstorm

C. P. R. SAUNDERS; BAX-NORMAN HOLLY; R. MITZEVA; B. TSENOVA; E. E. AVILA; N. E. CASTELLANO

Blackpool, Inglaterra

Conferencia; International Conference on Lightning and Static Electricity; 2003

Collisions between vapour grown ice crystals and a riming target, representing a graupel pellet falling in a thunderstorm, have been shown in an extensive series of laboratory simulations to transfer substantial charge, which is adequate to account for the development of charge centres leading to lightning in thunderstorms. Early experiments carried out in the laboratory in UMIST found the sign of the charge transferred to riming graupel pellets to be dependent on the cloud liquid water content and on cloud temperature.  Subsequently the dependence of charge transfer on velocity and ice crystal size was identified and incorporated in a parameterisation of charge transfer sign and magnitude in a form suitable for use in numerical models of thunderstorm electrification.