308 Fractal characteristics of simulated and LMA-detected lightning flashes

Monday, 24 January 2011
Washington State Convention Center
Blake J. Allen, University of Oklahoma, Norman, OK; and E. R. Mansell and E. C. Bruning
Manuscript (1.2 MB)

Handout (12.1 MB)

While the fractal dimension of lightning has been studied using both models and observations in the past, both types of studies suffered from limitations that are now avoidable. Due to a lack of computing power and model sophistication, the fractal dimension of simulated lightning has previously only been studied using either two-dimensional models or uni-directional, three-dimensional (3D) models with extremely simplified charge distributions. Also, due to a lack of modern observing networks, previous studies of the fractal dimension of observed lightning were limited to analyzing photographs of flashes in which channels exited the cloud.

In this study, the fully 3D, bi-directional lightning model of Mansell et al. (2002) has been used to simulate lightning flashes within modeled storms with realistic charge distributions at resolutions as fine as 25m. The fractal characteristics of these flashes have been analyzed by calculating two different measures of fractal dimension: The correlation dimension and the box-counting dimension. In addition, the fractal characteristics of lightning flashes detected in 3D by the Oklahoma Lightning Mapping Array (OK-LMA) have also been analyzed using the aforementioned measures.

Comparisons between the simulated and observed flashes will be presented and implications for tuning parameters in the lightning model will be considered.

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