Influence of electrification on microphysical and dynamical processes in a numerically simulated thunderstorm

A new three-dimensional dynamics and electrification coupled model is developed to investigate the influence of electrification on microphysical and dynamical processes in thunderstorms. This model includes a four-class ice microphysics scheme, five electrification mechanisms, and lightning parameterization. Comparisons between model results and observations reveal that the dynamics and electrification coupled model is capable of reproducing many of the observed characteristics of the thunderstorm in dynamical, microphysical, and electrical aspects. The effects of electrification on microphysical and dynamical processes are examined by performing two numerical experiments, one with electrification processes and the other without them. Results show that when electrification processes are included the mass transfer among hydrometeors in microphysical processes, especially collection and coalescence processes, changes considerably as a result of significant modification of the terminal velocities of large precipitation particles. The change of mass transfer in microphysical processes affects cloud buoyancy by changing the amount and distribution of hydrometeors, and latent-heat release in the middle region of the thunderstorm increases. That is, convection strengthens by including electrification processes. The amount of solid precipitation and the diameter of solid precipitation particles at the surface increase because a stronger updraft sustains large precipitation particles and prevents them from falling out of the cloud earlier.