Production of ice crystals and electric charge by splintering of freezing droplets in thunderclouds

According to the Mason‐Latham mechanism the main thunderstorm charge is generated by the impaction, freezing and splintering of supercooled droplets on pellets of soft hail. The rates of charge and splinter production are now calculated using the Ludlam‐Browning model of the thunderstorm. The riming mechanism appears capable of producing charge at the required rate of about 1 amp in the region of strong updraught if large cloud droplets of r > 25 μ are present in concentrations of ∼ 10 cm−3 near the 0$C level. Splintering of these droplets while freezing on pellets of soft hail would produce ice crystals in concentrations about one‐tenth those of the large droplets between the — 20$C and — 30$C levels. The calculations indicate that the bulk of the thunderstorm charge cannot be generated and separated in regions of weak updraught because the production of splinters would lead to rapid glaciation of the cloud and the disappearance of supercooled water droplets.