Simple calculations predict that the lightning frequency f is proportional to the product of the downward flux of solid precipitation through the body of the thundercloud and the upward flux of ice crystals into its anvil. This prediction is reinforced by more elaborate computations performed using the multiple lightning model of Baker et al (1995, 1999).
An examination of data from the Lightning Imaging Sensor (LIS) and the TRMM Microwave Imager (TMI) suggests that thunderstorms with the highest frequency of total lightning also possess the most pronounced microwave scattering signatures at 37 and 85 GHz. A total of 292 individual thunderstorms were examined, and a log-linear relationship was shown to exist (one for each frequency) between the number of optical lightning pulses produced by each storm and the corresponding microwave brightness temperatures. These relationships are consistent throughout the seasons in a wide variety of regimes , suggesting that global relationships exist between lightning activity and cloud ice content.