Three Dimensional Analysis of Bipolar Lightning in Winter at the Japan Sea Coast.

对冬季的观测一直在继续使用磁链、用于当前示波器图的数字记录系统、现场磨机、静止照相机和用于日本西海岸闪电通道图像的摄像机系统。为了弄清冬季雷雨云的结构，我们制作了3个慢速天线，安装在相距几百米的点上。在65个磁链记录中，60%为负极性，28%为正极性，其余12%为未知极性。正闪时最大峰值电流大于300 KA，正闪时峰值电流较大。测得的电流波形图显示，冬季闪电的持续时间往往很长。两种类型的双相卒中在冬季较为常见。60次闪光中有9次显示双相中风。对地表垂直势梯度和冬季雷暴发生的天气条件进行了研究。观测到的静电场信号在量级和极性上变化很大，经常超过20千伏/米。表面梯度经常在几分钟内改变为相反的极性。在一天或更长的时间里，几场雷暴形成并周期性地袭击了该地区。许多由照相机和摄像机拍摄的照片显示，大多数闪光都有向上的分支。所有九个双极示波图都类似于两种类型中的一种或另一种。第一种类型最初有一个低的负电流，然后一个大的正电流。另一方面，第二种类型从一个大的正电流开始，随后叠加一个负电流，然后变成负电流。双极中风通常发生在雷电电流相对较小的时候。这表明双极电流从雷雨云中不同极性的某些区域逐渐通过同一通道。此外，双极闪电的回击电流与反向电流脉冲的叠加也具有重要意义。少

The observation of winter has been continuing using magnetic links, digital recording systems for the current oscillograms, field mills, still cameras and video camera systems for the images of lightning channels at the west coast of Japan. To clarify the structure of winter thundercloud, three slow type antennas were made and installed at the points which are separated several handred meter apart from earch other. Of the 65 magnetic links records, 60% were negative in polarity, 28% were positive and the remainig 12% were unknown. The maximum crest current was over 300 KA in a positive flash, and the larger crest currents were found in positive flashes. The measured current oscillogram shows that a winter lightning often has a very long duration. Moreover two kinds of bipolar strokes were frequently recorded in the winter season. Nine of the 60 flashes showed bipolar strokes. The vertical potential grdient at earth's surface and the wether conditions for the occurrence of winter thunde … More rstorms were studied. The observed signals of the electrostatic field were very variable in both magnitude and polarity, and often exceeded more than 20 kv/m. The surface gradient frequently changed to the opposite polarity in a few minutes. Several thunderstorms developed and attacked the region periodically over a long period of time during one day or more. Many photographs taken by sitll cameras and video cameras show that most of the flashes have upward branching. All nine of the bipolar oscillograms were similar to one or the other of two types. The first type initially has a low negative current and then a large positive current. The second type, on the other hand, begins with a large positive current, with a negative current subsequently superimposed on it, then change to a negative current. Bipolar stokes generally occur when lightning currents are relatively small. This would suggest that the bipolar current is gradually passing through the same channel from some regions of different polarity in the thunderclouds. Moreover it is significant that the return stroke current of bipolar lightning was superimposed with the opposite current pulses. Less