The Systematic Observation of the Thundercloud and Lightning

系统的雷暴观测是在1993年的雷暴季节在佛罗里达州的奥兰多进行的。日本科学家小组则利用新开发的宽带慢速天线，在两个不同点同时进行电场变化观测。义阜大学利用摄像机和保持高空间分辨率的光学测量系统对一个闪电通道进行观测，可以得到闪电通道在直径方向上的变化情况。岐阜大学还配备了一套光学测量系统，他们可以用它来区分所谓的同步多点雷击的时间差。另一方面，在美国，国家强风暴实验室（NSSL）被指派使用手工制作的全天空相机拍摄闪电通道的高速视频图像。新墨西哥理工学院负责操作雷雨云一侧闪电通道的甚高频成像系统。由于雷击放电是一种短暂现象，有时不到1秒，因此多点观测最费力的工作是通用准确时间标准的操作。我们通常使用瞬态存储器来记录观测到的信号，而产生共同的触发信号往往比较困难，我们将两个相距2.5公里的慢速天线安装在一起，我们决定使用闪电放电发出的发光信号作为系统的触发信号。我们确信，在没有实时连接的情况下，在两个不同点记录数据的出色同步。我们在8月初有8天雷雨天气，并获得了许多较好的数据。这对于了解多点雷击同时发生的机理是有效的。分析工作在每个研究所进行。

The systematic thunderstorm observation was caraaid out at Orlando, Florida during the thunderstrom season in 1993. Concerning the Japanese scientist groups, Osaka University is assigned to the electric field change observation at the two different points simultaneously using the newly developed wideband slow antenna. Gifu University is assigned to the observation of a lightning channel by a video camera and by an optical measurement system which maintains the high spatial resolution and we can obtain an idea on the lightning channel variation in the direction of the diameter. Gifu University also equipped an optical measurement system with which they can discriminate the time difference of so called simultaneous multi point lightning strikes. On the other hand concerning the group of U.S., National Severe Storm Laboratory (NSSL) is assigned to taking high speed video pictures of lightning channels by a hand made whole sky camera. New Mexico Tech is assigned to the operation of the VHF imaging system of lightning channel in side the thundercloud.Since the lightning discharge is a transient phenomena which is sometimes shorter than 1 sec., the most laborious work for the multi point observation is the operation of the common and accurate time standard. Normally we use the transient memory to record the observed signals and To produce the common trigger signal is often difficult, We equipped the two slow antenna 2.5 km away each other and we decided that for the trigger signal of the systems The luminous signal emitted from lightnings discharges is used. We are convinced the excellent synchronization of recorded data at two different point without the real time connection.We had eight thunderstorm days in early August and captured many preferable data. Those are surely effective to understand the mechanism of simultaneous multi point lightning strikes. The analysis is undertaken at each Institute.