Propagation effect of lightning electromagnetic field along real ground surface and its validation on correcting lightning location system errors

Abstract

Artificially triggered lightning experimental data from Guangdong Comprehensive Observation Experimental Base on Lightning Discharge (GCOELD) was applied to analyze the propagation effect of lightning electromagnetic field along the real ground surface. The accuracy of the finite-difference time-domain (FDTD) on correcting lightning location system (LLS) errors was validated compared with the Elevation Model (EM). Results show that the wave-shape and time-delay of electromagnetic fields can be significantly affected when they propagate over the real ground surface. The time-delay of the field waveform become larger with an increasing roughness. The wavefront electric field is enhanced due to the reflection and variant of the wave when lightning waves propagate across the high and sharp terrain. Near the lightning strokes, the peak of vertical electric value decreases significantly with the electrostatic shielding effect. The max time delay calculated by FDTD is 8.34 μs; while that by EM is 6.55 μs. In the selected nine lightning stroke points, eight are positively revised by EM, and five by FDTD. Both FDTD and EM can be used on LLS error revision caused by the real ground surface around GCOELD, although EM is more efficient than FDTD in this case.