2012 Volume 132 Issue 6 Pages 579-587
The performance of the IMPACT sensor network in the Tohoku region for winter lightning detection was evaluated referring to another study of winter lightning in the coastal area of the Sea of Japan. The detection efficiency for lightning flashes causing transmission-line faults was 62%, but decreased to 56% for the first lightning strokes. Classifying these first lightning strokes, the detection efficiencies were 23% for -GC strokes, and 67% for +GC strokes. GC strokes accounted for 73% of the entire group of investigated strokes, and rejected GC strokes also accounted for 95% of all rejected strokes. In analyzing the LEMP waveforms, it was found that the rejection was caused by an incompatibility of the characteristics of the LEMP waveform with the waveform discrimination criteria, and the influence of the field pulses prior to the main pulse on the signal processing in the IMPACT sensors, which could be reduced through the propagation effect.