Thunderstorm electrification

Figure 1 shows the mean annual distribution of the fractional area covered by clouds whose tops are above the 440 mb pressure level. All these clouds are likely to contain ice. The total atmospheric burden of ice is not known, but very crude estimates suggest it is around 10 to 10 kg. This mass is small compared with that (over 10 kg [5]) in surface ice and snow. Despite its relatively small abundance, atmospheric ice has considerable impact on global climate, the chemical composition of the atmosphere and of precipitation, and on thunderstorm electrification. Figure 2 represents the ice-related tropospheric processes to be discussed in this paper, and we will refer to this figure in succeeding sections. 

Takahashi, T. Riming electrification as a charge generation mechanism in thunderstorms. J. Atmos. Sci. 35, 1536-1548, 1978. 

---