摘要
通常将通过闪电光学观测得到的回击光学发展速度等同于回击电流发展速度,报道结果显示,回击速度沿闪电通道从下往上发展逐渐减小。本文指出闪电回击发展存在径向路径光学传输路径差效应,观测得到的回击发展速度与真实速度存在差异,定义了视在回击速度,研究了光学观测点在地面以及地面以上等情况下视在回击速度的变化特性,发现视在回击速度沿闪电通道从下往上逐渐减小且与真实速度的偏差随真实速度的增加而增大,提出了考虑光学传输径向路径差效应的回击光学发展速度的计算方法。
A varying return-stroke speed during the propagation process along the lightning channel is extensively reported.In this paper,we found,due to the propagation time difference of the emitted light by lightning in the propagation path from the lightning channel to the optical observation point,even in the case of an assumed constant return-stroke speed,the observed speed,termed as the apparent return-stroke speed,is not constant.For conventional return-stroke engineering models that the return stroke is assumed to propagate from the ground,we investigated the influence of the observation distance,the observation altitude,and the assumed value of the return-stroke speed on the variation trend of the apparent speed.In addition,the deviation of the apparent speed from its actual value is compared for the concerned influencing factors.The need of propagation time correction in obtaining the characteristics of return stroke propagation from the time-resolved optical records is emphasized here.
出处
《科技创新导报》
2017年第23期88-90,共3页
Science and Technology Innovation Herald
关键词
电磁场
雷电
回击速度
Electromagnetic fields
Lightning
Return-stroke speed
