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

Table 2

Errors of the waveform rise time () of the vertical electric field calculated by our approximate method for different earth conductivity () and propagation distances ().

(S/m)	(km)	Waveform rise time (μs)		Error () (%)
		Wait’s formula ()	Our approximate formula ()
4	200	6.7	6.7	0.0
	500	8.2	8.1	−1.2
	1000	11.4	11.5	0.9
	1500	15.7	15.7	0.0
0.01	200	7.7	7.8	1.3
	500	9.7	9.7	0.0
	1000	13.7	13.7	0.0
	1500	18.6	18.3	−1.6
0.001	200	10.3	10.3	0.0
	500	13.8	13.7	−0.7
	1000	19.8	19.3	−3.0
	1500	26.2	25.2	−3.8