中文摘要：

为加深对北京地区雷电特征的认识，并为北京地区的防雷设计提供依据．利用2008—2009年快、慢天线雷电电场变化仪得到的资料对北京地区的雷电物理特征进行了统计分析。结果表明，每次地闪回击数频率分布和回击间的时间间隔都呈现出明显的正态分布特征。单次回击地闪的比例高达45％，平均地闪回击为3次，观测到的最大回击数为15次。相邻两次回击间隔时间在40ms和110ms出现峰值，观测到的最短回击间隔为2．2ms，回击间隔分布在40～100ms之间的高达60％以上。373例继后回击与首次回击强度之比平均为0．65，13％的地闪过程中至少有1次比首次回击强的继后回击。继后回击幅度较强，通常会伴随较短的先导持续时间和较长的回击间隔。

英文摘要：

The physical characteristics of lightning flashes occurred in Beijing area have been analyzed by using the instruments such as the electric field mill, fast and slow antennae during the year of 2008 and 2009. It has been found that the number of strokes per flash shows an exponential-decay distribution;single-stroke flashes reach up to about 45% of total flashes;the average number of strokes per flash is 3 and the maximum number is 15. The interstroke interval does not show simple and normal distribution with the peak value of 40 ms and 110 ms. The minimum value of interval stroke is about 2. 2ms,and the intervals between 40ms and ll0ms account for about 60%. The average ratio of the subsequent return stroke and the first return stroke is 0. 65 among 373 cases,while about 13% of ground flashes have at least one subsequent stroke whose initial peak is greater than that of the first stroke. Lager subsequent strokes are associated with relatively shorter leader duration and longer interstroke interval.