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通过对1998年8月22日空中引发雷电先导过程的光、电观测资料的综合分析发现，在空中引发雷电的先导系统中存在三个先导过程。①向下发展的负先导在起始阶段呈小阶梯特征，阶梯之间的时间间隔约为20μs，阶梯的上升时间小于1μs，随着负先导的下行发展，梯级增长。②金属导线上端向上发展的正先导在负先导接地之后，表现出明显的阶梯特性，阶梯之间的时间间隔平均为15μs。③从地面向上发展的连接正先导由多个振荡脉冲组成，脉冲之间的时间间隔约为13μs，连接先导的发展也是梯级的。电场快变化中的高频分量随着距离的增加衰减很快。最强的发光是由向下的负先导接地时形成的小回击产生的，强光只集中在空气离化而形成的放电通道部分，光强则随着高度的增加很快衰减，其传播速度约为2.1×108m.s-1。在小回击发生之前，向下发展的负先导在接地之前有较强的发光，而金属导线上端向上发展的正先导没有明显的发光。在小回击发生之后，金属导线上端向上正先导的发光强度被增强，其向上的传播速度约为2.4×106m.s-1。金属导线部分在小回击发生之后约220μs逐渐开始熔化发出强光，并向上发展而与前面向上发展的正先导的发光相并合，其传播速度约为1×106m.s-1。“,”The optical and electrical data of triggered lightning inaltitude on 22 August 1998 were analyzed. The results indicated that there were three leader processes in triggered lightning in altitude. A negative leader propagated downward from bottom end of wire in a discontinuous pulses pattern with intervals of about 20 μs and rise time of less 1 μs. A positive leader starting from the top end of wire showed a pulses pattern with the intervals of 15 μs after the negative leader reached the ground. Meanwhile, a positive leader was initiated from the ground and propagated upward in discontinuous pulses pattern with intervals of 13 μs when the negative leader approached the ground. Following this was a mini-return stroke which emit intense light only in the channel section between ground and bottom end of wire and had an upward speed of 2.1×108 m.s-1. The negative leader emit more intense light than the positive leader initiated from the top end of wire before mini-return stroke. The light emit by the positive leader initiated from the top end of wire was intensified and propagated upward in speed of 2.4×106 m.s-1 after mini-return stroke. The wire was melted after 220 μs of mini-return stroke and had intense light which propagated upward in speed of 1.0×104 m.s-1