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

Table 1

Relative errors of the peak value () calculated by our approximate method for different earth conductivity () varying from 0.001 S/m to 4 S/m. The propagation distances () between lightning and observation point ranges from 200 km to 1500 km.

(S/m)	(km)	Peak value (V/m)		Error () (%)
		Wait’s formula ()	Our approximate formula ()
4	200	1.070	1.070	0.0
	500	0.349	0.349	0.0
	1000	0.111	0.111	0.0
	1500	0.046	0.046	0.0
0.01	200	1.068	1.066	−0.2
	500	0.350	0.346	−1.0
	1000	0.113	0.110	−2.4
	1500	0.047	0.045	−3.3
0.001	200	1.030	1.024	−0.6
	500	0.330	0.321	−2.6
	1000	0.108	0.101	−6.2
	1500	0.046	0.042	−8.7