Introduction
摘要
At any given time, there are about 2000 thunderstorms on our planet. Based on ground and satellite measurements, it has been estimated that between 30 and 100 lightning strikes occur on Earth every second. Over the course of a day, there can be up to 9 million lightning strikes on the globe. However, the geographical distribution of lightning is not homogeneous. The frequency of thunderstorms decreases continuously from the equator to the polar regions.