Dynamic and Electrical Sensitivities to CCN Concentrations within the Simulated 29–30 May 2004 Geary, Oklahoma, Supercell Thunderstorm

Abstract:

Cloud condensation nuclei (CCN) are known to affect both the electrical and the dynamic evolution of storms, but the effects on storm electrification in different storm modes has not been thoroughly examined. We will detail the impacts of CCN in simulations of the high-precipitation Geary, Oklahoma supercell storm from the Thunderstorm Electrification and Lightning Experiment (TELEX) on 29-30 May 2004. The simulations were run and analyzed using five different CCN concentrations (100, 300, 500, 1000, and 2000 cm^-3) in the Collaborative Model for Multi-scale Atmospheric Simulation (COMMAS), a three-dimensional cloud model with a bulk electrification scheme. Simulations were run using a three-moment microphysics scheme with six hydrometeor types and utilizing both inductive and non-inductive charging for electrification. The simulations provide details on storm dynamics, kinematics, and electrification that cannot be observed directly with a controlled change in a single variable, the CCN. The CCN concentration of each model run significantly affected the storm dynamics, kinematics, and electrification in this high precipitation storm . There were differences in storm polarity, the location and timing of electrification across the different CCN concentrations. Very low CCN concentrations had opposite polarity than that of higher CCN concentrations. The overall evolution of the storm also differed with CCN concentration including the spatial extent (horizontal and vertical), lifetime of the storm, evolution of warm and cold rain processes, and the speed and volume of the updraft.