Lightning data and resource exploration

Abstract

The process of lightning begins within a thunderstorm when supercooled (with a temperature well below freezing, but not frozen) droplets and/or ice collide and electrons are separated from, or added to, molecules (ionization) as shown by Rakov and Uman (2003). The neutral atmospheric molecules (droplets, ice or other suspended particles) become electrically charged as they collide with other particles with a greater or lesser amount of energy. The electrical discharge initiates as a channel of high ionization propagates through the air. This can occur with both positive and negative charges. Such channels are the beginning of a leader that reaches toward the ground in a cloud-to-ground discharge as it initiates the first return stroke. This may occur after cloud-to-cloud discharges have occurred over distances up to 200 km or more. The first stroke is initiated by a stepped leader. In a typical event, the flash of the first return stroke ascends as soon as the descending stepped leader makes electrical contact with the ground. In many cases the process is aided by short ascending ground streamers which seem to almost explode or radiate with a greater intensity. The return stroke is what produces most of the brilliant light associated with lightning and it is also where most of the electrical charge transfer takes place as discussed by Rakov et al. (2005). All of the subsequent strokes are initialized by a dart leader usually following the same channel as the stepped leader and thus the appearance or form of the lightning tends to look the same with the remaining return strokes.