EXPERIMENT OF ARTIFICIALLY TRIGGERING LIGHTNING IN CHINA

Triggering lightning experiment with rocket-wire technique was conduct ed in Gansu, northwestern China. Ten cases of triggered lightning were obtained in three summers from 1989 to 1991. They were all with posit ive electric Field at ground (positive charge overhead) under the infl uence of dominant lower positive charge of Gansu thundercloud. Trigger ed lightnings were weak discharges initiated by upward moving negative leaders followed by continuous current processes. No dart leader-retu rn stroke processes were observed. The discharge lasted about several tens of miliseconds with a peak current of only a few hundred amperes. Simple physical models are used to evaluate the velocity of leader pr opagation, magnitudes, and altitudes of the charge transferred by trig gered lightnings. Results are consistent with the features of lower po sitive charge of Gansu thunder storms.