Observations of Lightning Flash Characteristics in Turbulent Environments of Thunderstorms

Previous studies have shown that lightning flash rates and size closely follow changes in thunderstorm kinematics. It has therefore been suggested that the intensity and size of thunderstorm updrafts, determines the rate of flash production and size. Additionally, a relationship between the turbulent kinetic (TKE) and total flash energies in these environments, as a function of flash size, has been theorized. However, observations and comparisons of flash and turbulent kinetic energies have not been made.

This study used the Texas Tech Ka-Band radars and the West Texas Lightning Mapping Array (LMA) to further explore the characteristics of lightning flashes in highly turbulent environments. These data were obtained from the Kinematic Texture and Lightning (KTaL) field project operated by Texas Tech in the 2014-2016 Spring-Summer seasons. Seven cases are presented of different storm modes that account for variability in turbulence and lightning characteristics. Radar derived eddy dissipation rate was used to estimate the total TKE for each radar scan for direct comparison to LMA data fields of flash initiation, extent, footprint, and total energy densities. Statistical comparisons were then made by identifying local regions of high turbulence to make one-to-one comparisons of maxima in LMA fields with maxima in TKE as the storm moved through the radar scan plane. Preliminary results suggested a high correlation between flash initiation and total energy density and the total TKE, which supports the idea of a coupling between TKE and flash rate and their energetics.