高建筑物上闪电普通摄像观测与分析

Video Observation and Analysis of Lightning Striking on Tall Buildings in Guangzhou

2009—2010年夏季,在广东省气象局对东南方向的高建筑物上的闪电进行了观测。对获得的普通摄像资料进行了处理和分析,基于对闪电事件引起普通摄像中像素亮度变化的分布特征的分析结果,编写了视频资料处理程序,实现了普通摄像资料中闪电图片的自动提取。在此基础上,统计分析了观测到的广州高建筑物上87次自然闪电的特征,结果表明:这些闪电的持续时间平均为348ms;对于高度超过500m的建筑物,其上发生闪电的次数明显多于高度低于500m的建筑物,且闪电的平均持续时间也更长。给出了拍摄到的几幅云下闪电通道呈现蛛状和长距离特征的闪电图片。

In the summers of 2009 and 2010,observation experiments of lightning flashes striking on tall buildings to the southeast of Guangdong Provincial Meteorological Service were conducted.The video recording data obtained by ordinary cameras were processed and analyzed.Based on the characteristic analysis of pixels number distribution with different brightness variation values,a video data processing program was devised to extract lightning pictures from video recording data.The characteristics of natural lightning on tall buildings in the viewing range were statistically analyzed.The results show that the mean duration of 87 natural cloud-to-ground lightning striking on tall buildings in Guangzhou is 348 ms.By comparing the lightning flashes striking on buildings higher than 500 m with those with heights from 100 m to 500 m,the average number for the former is significantly larger than that of the latter,and the mean duration of the former is longer.Some video images of 'spider' flash and long discharge are also presented.