Possible effect of the ground altitude on the lightning striking distance

A simple self-consistent propagation model of bi-directional leader with a streamer zone in front of the lead tip was developed. The model enables the calculation of leader channel parameters, such as leader charge density, leader current, leader potential, and lightning striking distance to flat ground. According to the leader potential concept recently proposed by Mazur and Ruhnke, the lightning striking distance is directly related to the critical electric field in the negative streamer zone in front of the leader tip and to the leader potential. The former is apparently dependent on the ground altitude above sea level and the latter may also affected by it. Based on the Mazur's leader potential concept and this leader model, the effect of regional ground altitude on lightning striking distance was investigated. The result shows that the striking distance increases significantly as the ground altitude increases. This is mainly due to that the critical electric field necessary for sustaining the negative streamer zone decreases as the ground altitude increases. It also shows that the leader potential and the total charge transferred by the return stroke are ground altitude dependent. This means that the relationship of the striking distance versus the prospective return stroke peak current is also the ground altitude dependent. The result is useful to both physical and engineering applications.