青藏高原那曲地区雷电特征初步分析

通过对2002年夏季青藏高原那曲地区雷暴过程及闪电观测资料的初步分析，发现该地区雷暴电荷结构具有多样性和复杂性，地闪明显偏少. 对高原地闪的一些基本特征参量的统计分析表明，无论正地闪还是负地闪梯级先导前都具有持续时间较长的云内放电过程，地闪以单次回击为主. 与中低纬度地区相比，高原地闪中正地闪比例明显要高，为33髎；负地闪为67髎；正、负地闪回击后常常伴随短时间的连续电流.

PRELIMINARY ANALYSIS OF CHARACTERISTICS OF LIGHTNING IN THE NAGQU AREA OF THE QINGHAI-XIZANG PLATEAU

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.