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Characteristic of Lightning Channel in the Thundercloud from Thunder

雷电云中闪电通道的特征

基本信息

批准号：
02650210
负责人：
WAKAMATSU Masatoshi
金额：
$ 1.28万
依托单位：
NUMAZU COLLEGE OF TECHNOLOGY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1992
项目状态：
已结题

项目摘要

We measured 23 thunder records at Numazu near Mt. Fuji on May in 1992, and at Tubata and Shishiku Heights near Kanazawa in winter since 1990. (1) Thunder signatures are classified into three types. The first type is that the largest sound arrives within 0.5 sec at the outset and after that becomes gradually weaker. The second type is that weak sound comes first and becomes stronger step by step and after that gradually weakens. The third type is that the first or the second type repeats. (2) The mean duration of thunder is 20 sec in winter thunder. The thunder of the third type is observed in winter lightning and has almost long duration more than 30 sec. (3) The dominant frequency of power spectrum is 140 Hz on the average, the nearby thunder less than 5km to main channel is 150Hz, on the other hand the thunder of long distance more than 5km is 67Hz.It is shown that the channels of long duration thunder are reconstructed by determining the time window length from zero-crossing number, and the channels of a multistroke lightning are reconstructed from the dominant thunder signals.The spatial resolution of sound source location is made clear from the relation sampling period of thunder data and microphone configuration. When four microphones are located at the origin and on right angled axes in equal separation of D meaters, the resolution is less than 2ROO<3>DELTAS/D for any directional sounds, where DELTAS is sampling error.The lightning channels are reconstructed from the winter thunder and the following results are derived : (1) Lightning of simultanous strokes to different points presents occasionally the third type of thunder. (2) The center of lightning channels is in the range 1.5km and 2km altitude and the horizontal channel is longer than 15km in horizontal extent.

我们在Numazu附近测量了23次雷电记录。1992年5月在富士，自1990年以来冬季在金泽附近的图巴塔和石鼓高地。(1)雷电信号分为三种类型。第一种类型是最大的声音在开始时在0.5秒内到达，之后逐渐变弱。第二种类型是先有微弱的声音，然后逐渐变强，然后逐渐减弱。第三种类型是第一种类型或第二种类型重复。(2)冬季打雷平均持续时间为20s。第三类雷电是在冬季闪电中观察到的，持续时间几乎很长，超过30秒。(3)功率谱的主频平均为140 Hz，距离主通道小于5 km的雷电为150 Hz，距离主通道5 km以上的雷电为67 Hz。通过由过零数确定时间窗长度来重建长持续时间雷电的通道，由主雷信号重建多冲程闪电的通道。通过雷电数据采样周期与传声器配置的关系，明确了声源位置的空间分辨率。当四个传声器位于原点和直角轴线上时，对于任意方向的声音，其分辨率都小于2ROO；lt；3；；D，其中增量是采样误差。从冬季雷电重建闪电通道，得到以下结果：(1)不同点同时击打的闪电偶尔会出现第三类雷电。(2)闪电通道中心在1.5~2公里高度范围内，水平通道水平范围大于15公里。