Radio emission from clouds

Radio emission from clouds, not associated with lightning, has been observed and recorded as such on several occasions. Since the source of this radiation cannot be the lightning discharge, a study has been started to explain its nature and origin. Preliminary studies have revealed radio emission from colliding charged water drops at frequencies of the order of tens of megacycles, possibly higher. Microwave radiation is known to result from the contact of charged mercury drops with a grounded probe. We find microwave radiation from the contact of mercury drops with glass, plexiglass, or a pool of mercury. Plans are discussed for using the mercury drop radiation phenomenon as a control in studying the radiation from cloud drops.