PRELIMINARY ANALYSIS OF CHARACTERISTICS OF LIGHTNING IN THE NAGQU AREA OF THE QINGHAI-XIZANG PLATEAU
青藏高原那曲地区雷电特征初步分析

We analyzed the data of electric field and electric field changes produced by lightning on the ground in the Nagqu area of the Qinghai Xizang plateau in the summer of 2002. The results showed that the charge structure in thunderstorms was multiformity and complication. Little cloud to ground (CG) lightning flashes occurred in the thunderstorm. A long time discharge process in cloud occurred just before the step leader of positive and negative CG lightning. Most of CG lightning discharges only involved one return stroke. The proportion of positive CG lightning discharges was 33% and negative 67% in thunderstorms. It was obviously higher than that in lower and middle latitude area. A continuing current process with short lasting time occurred just after the return stroke.