Analysis of the Effects of Ground Resistivity on the Lightning Radiation Fields Based on FDTD Method

In order to investigate effects of ground resistivity on the lightning radiation electromagnetic fields produced by lightning return-stroke, a three-dimensional finite-difference time-domain (FDTD) numerical model is developed with lightning current´s transmission line model. Lightning radiation electromagnetic fields at the flat ground are calculated and effects of different soil resistivities on lightning radiation electromagnetic fields are compared, which make a great contribution for predicting the lightning electromagnetic environment accurately in various geological conditions. The computed results indicate that the resistivity of the monolayer ground has greater effects on the lightning radiation electric field than the magnetic field. Effects made by the horizontal stratified ground mainly lie on the resistivity of the upper ground and the vertical stratified ground´s resistivity affects radiation fields slightly. Numerical results have proved that the numerical solution is in good agreement with the analytical solution, which shows the reliability of the computed results in this paper.