Lightning-flash counter using pattern recognition to discriminate between ground and cloud flashes

Electric-field changes caused by lightning flashes have characteristic features related to the type of discharge involved, which have been used as the design basis of a discriminating lightning-flash counter. Provided that the overall magnitude of the electric-field change exceeds 230 V/m, the counter registers a ground flash if the largest positive step in the field change exceeds 0·25 of the overall magnitude, and a cloud flash otherwise. Preliminary results indicate that significantly better discrimination is achieved than in the CIGRE lightning-flash counter.