Discussion on location accuracy improvemed by propagation delay corrections for the Japanese lightning detection network

The location accuracy of the Japanese Lightning Detection Network (JLDN) has been evaluated for a long time. It was reported that the average location accuracy of the JLDN was approximately 0.44 km for return strokes of negative downward lightning striking wind turbines in summer and 0.58 km for return strokes associated with upward lightning initiated from wind turbines in winter. However, the authors found that many stroke positions calculated by the JLDN tended to be located in specific directions. Therefore, we assumed this was caused by differences in the propagation speed of the electromagnetic waves that emitted from lightning discharges, passing along surfaces of varying conductivity. We recalculated the lightning positions of strokes that hit the wind turbines after applying propagation delay corrections. The difference between the times measured at the sensor and calculated times was smaller after the recalculation. As a result, location accuracy was improved from 0.44 km to 0.31 km for downward lightning strokes in summer, and it was improved from 0.79 km to 0.12 km for lightning strokes in winter.