Why does lightning enhance the global electric field instead of dispelling it?
The answer lies in the structure of thunderstorms. For reasons unclear–but probably involving millions of collisions among ice crystals and small hailstones or graupel–storms evolve with positive charge near the top and negative charge from middle to cloud base. In a typical cloud-to-ground strike, negative charge descends from cloud base to ground. In response, trees, poles, and other objects release positive charge upward–thus keeping the earth’s overall charge negative.
