Characterizing Pulse Attenuation of Intra-Cloud and Cloud-to-Ground Lightning with E-Field Signal Measured at Multiple Stations

Abstract

In this paper, we analyze the waveform data of nearly 200,000 intra-cloud (IC) and cloud-to-ground (CG) lightning discharges detected by the Jianghuai Area Sferic Array on 26–29 August 2019 to investigate the propagation features of lightning electromagnetic fields. Through the analysis of variation in the electric field (E-field) signal of lightning during the actual propagation, it was found that (1) the attenuation of lightning E-field signal with distance can be fairly well described by the power-law relationship E = ar−b, and the attenuation index is b = 1.02 (for IC) and b = 1.13 (for CG); (2) under the situation of the same propagation path, the IC pulses experience less attenuation than CG pulses; and (3) through the comparison with simulations, it can be seen that the attenuation of lightning E-field pulse is affected by the conductivity of the ground surface, and according to the attenuation factor of lightning E-field strength, it can be inferred that the conductivity in the Jianghuai area ranges between 0.005 S/m and 0.01 S/m, which is in good agreement with the measured conductivity in this area. Our results suggest that lightning radiation could provide a feasible means for remotely sensing the ground conductivity.