Improved lightning locations in the tohoku region of japan using propagation and waveform onset corrections

As part of an ongoing collaboration between Tohoku Electric Power Company, Vaisala, Sankosha, and the University of Arizona, propagation corrections have been implemented in Tohoku's two overlapping LLS networks: a 6-sensor LS700x research LLS and the operational 9-sensor IMPACT (141T) LLS. In addition, new arrival-time onsetcorrections have been implemented in the six LS700x sensors. Sensor arrival-time consistency was improved by (roughly) a factor of two in the older IMPACT LLS (as a result of propagation corrections), and more than a factor of three in the new LS700x LLS (propagation and onset corrections). Estimates of "relative" location accuracy (LA) improvements, based on an analysis of location differences for return strokes that shared the same ground strike point, indicate that the IMPACT LLS median LA improved from ~400m to ~270m using propagation corrections, and that the LA for the LS network is ~100m using both propagation and onset corrections. Analysis of return stroke locations produced by the LS network that were associated with four transmission line faults showed locations that were between 60m and 390m from the verified fault location. The actual line-attachment locations cannot be determined, so these errors are likely an upper-bound on the actual location error.