A New Approximate Method for Lightning-Radiated ELF/VLF Ground Wave Propagation over Intermediate Ranges

Figure 1

Comparison of the simulated amplitude of attenuation functions in the frequency domain calculated by our Newton–Raphson root-finding codes and that presented by Shao and Jacobson [5]. The solid lines are computed for a spherical earth with an assumed conductivity of 0.02 S/m. The dashed lines are for a planar earth with the same conductivity, and only 200 and 500 km path lengths are presented for the planar earth. Note that the attenuation function value presented here is twice as much as the calculated value by (3), because Shao and Jacobson [5] included the mirror effect of perfectly conducting ground in the attenuation function.