10:15 〜 10:30
[MIS26-06] 蔵王で観測された北陸冬季雷と関係する下部電離圏におけるLF波の乱調
キーワード：lightning, subionospheric perturbations, electromagnetic pulses, quasi-electrostatic fields
Intense electromagnetic pulses (EMP) radiated from lightning discharge could cause heating and ionization and alter the conductivity in the ionospheric D-region. Quasi-electrostatic fields (QE Fields) which are generated due to the removal of electric charge could also affect it. The purpose of this study is to reveal influence of the lightning on the lower ionosphere and its dependence on properties of lighting discharges. The VLF/LF signature of subionospheric perturbations associated with winter lightning in the Sea of Japan (around Hokuriku) has been observed during December 16-31, 2009. LF (60kHz) radio observation was made at Zao (Miyagi) for Haganeyama JJY transmitter (border between Saga and Fukuoka) whose great circle path (GCP) passes over the coast area of Hokuriku. The amplitude and phase of the JJY signal are recorded every 0.1 seconds. In addition to the subionospheric LF observation, lightning locations are determined by a lightning location network (WWLLN). The number of total lightning event identified in the area of 35-37 degrees N and 134-137 degrees E is 1002. Based on the LF observation, subionospheric perturbations which occur immediately after the causative lightning (early event) were detected. The number of the total detection of the early event in the selected area is 72. Early events identified will be compared with peak current and charge moment of the causative lighting which are derived from LF and ELF waveform observations, respectively, to investigate the relation between early event properties and magnitude of EMP and QE fields.