Experimental Simulation of Lightning Optical Emissions in Clouds

Anil Ogale
Kunal Mitra
Arindam Banerjee, Missouri University of Science and Technology

This document has been relocated to http://scholarsmine.mst.edu/mec_aereng_facwork/3427

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The objective of the study is to experimentally determine the information content of lightning optical emissions through clouds. Clouds affect the amplitude of lightning signals and the apparent dimensions of the optical source. Multiple scattering from the cloud media also alters the shape of the temporal profile of the lightning signal. The goal is to provide accurate estimates of the arrival time delay and temporal pulse width broadening of output signals emitted from clouds for different cloud and lightning parameters. Experiments conducted in the laboratory yield a temporally broadened pulse with an overall decrease in the peak and a delay in the pulse rise time. Parameters such as optical thickness of the cloud medium and the scattering coefficients are varied to simulate different cloud properties. The experimental results are compared with a transient radiative transfer formulation solved using the discrete ordinate method. The practical implications of this research will be improved reliability on prediction of weather conditions, defence applications and geophysical app atmospheric studies.