Using a lightning mapping array (LMA), we have observed 24 positive cloud‐to‐ground (CG) flashes occurred in three thunderstorm days. These flashes can be apparently grouped into 5 clusters according to their occurrence times. We have obtained the charge structures for both the individual flashes and clusters. It was found that 4 out of 5 clusters of positive CG flashes exhibited either inverter dipolar or tri‐polar charge structures. This result indicates that the high percentage of positive CG flashes in Hokuriku winter thunderstorms originated from the inverted charge structure rather than the various deformations of normal charge structures widely accepted in literatures. The flash positive charge appeared to distribute usually in a layer with its thickness of around 1 km, its horizontal area of more than 100 km² and its bottom altitude of around 1–2 km above the ground. For each of the flash, we have also obtained its duration, length, duration before the first stroke and convex area. It was found that all flashes with a large peak return stroke current had short durations before their first return strokes. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

中文翻译：

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日本LMA观测到的冬季正向云对地闪电

使用雷电映射阵列（LMA），我们已经观察到在三个雷暴天中发生了24次正云到地面（CG）闪光。根据它们的出现时间，这些闪光显然可以分为5个簇。我们已经获得了单个闪光灯和簇的电荷结构。已发现，正CG闪光的5个簇中有4个表现出逆变器双极或三极电荷结构。该结果表明，北陆冬季雷暴中高水平的CG频闪来自倒装的电荷结构，而不是文献中广泛接受的正常电荷结构的各种变形。闪现的正电荷通常分布在厚度约为1 km，水平面积超过100 km ^2的层中且其底部海拔高度约为地面1-2公里。对于每个闪光灯，我们还获得了其持续时间，长度，第一次划水之前的持续时间和凸面区域。发现所有具有大的峰值返回冲程电流的闪光灯在其第一次返回冲程之前具有短的持续时间。©2021日本电气工程师学会。由Wiley Periodicals LLC发布。