Field identification of a unique globally dominant mechanism of thunderstorm electrification

Two wholly distinct studies involving TRMM-satellite global data were conducted. One involved the relationship between lightning frequency f and brightness temperature, the other between f and ice-water-path. Both studies demonstrate that globally valid relationships exist between f and thundercloud ice-precipitation content, from which it follows that graupel pellets play a crucial role in thundercloud charging. Ground-based field studies provide further support for this conclusion and show that f is also strongly dependent upon the ice crystal content. All these findings are consistent with the non-inductive charging mechanism, but not with any other proposed mechanism of thunderstorm electrification. We conclude that the non-inductive mechanism dominates electric field growth and lightning production in all seasons-for both oceanic and terrestrial thunderstorms -on a global scale. Copyright (C) 2007 Royal Meteorological Society.