We have performed a comparative study on the luminosity of 12 steps in an upward positive leader and eight steps in an upward negative leader recorded under similar conditions. Through analyzing their so‐called differential luminosity profiles along leader channels, we found that the steps of positive leaders can be classified into two types. The type I step luminosity is similar to the luminosity produced by a negative leader step and is generally featured with a rapid increase near the leader tip and accompanied by a backward propagation along the leader channel. The type II step is featured with continuous luminosity variation along the leader channel. No apparent backward propagation has been identified in the type II step luminosity of the positive leader. Based on these observations, we have discussed how the two types of steps of positive leaders are produced.

中文翻译：

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两个极性相反的上电闪电引线间断发光度的比较研究

我们对在类似条件下记录的向上正向引导者的12步和向上负向引导者的8步的光度进行了比较研究。通过分析他们沿着领导者通道的所谓的差异亮度分布，我们发现积极领导者的步骤可以分为两种类型。I型阶梯发光度与负引导阶梯产生的发光度相似，并且通常特征在于在引导尖端附近快速增加并且伴随着沿着引导通道的向后传播。II型台阶的特征是沿引导通道的亮度连续变化。在阳性前导者的II型阶梯发光度中没有发现明显的向后传播。基于这些观察，