双极性窄脉冲电场波形特征  

Characteristics of Electrical Waveform of Narrow Bipolar Event

作　　者：吴亭[1] 董万胜[1] 刘恒毅[1] 

机构地区：[1]中国气象科学研究院雷电物理与防护工程实验室,北京100081

出　　处：《高原气象》2011年第3期823-830,共8页Plateau Meteorology

基　　金：国家自然科学基金项目(41075022);科技部科研院所技术开发研究专项(2008EG137292)共同资助

摘　　要：利用2007年夏季野外试验取得的多站电场数据,通过一个较为宽泛的标准并配以手动判别的方法,挑选出14 871例双极性窄脉冲(NBE)的电场波形,对比分析了正、负极性NBE的3个基本特点:极窄的宽度、极大的峰值及孤立性。结果表明,两者的电场波形特征具有明显的差异。正、负极性NBE的脉冲平均宽度分别为6.42μs和5.46μs,并且正极性NBE的脉冲宽度更容易出现极大值,其最大值为19.76μs。正、负极性NBE的脉冲平均峰值分别为403.4和627.0数字单位,而同时期观测到的97 713例负地闪回击的平均电场峰值仅为256.7数字单位。负极性NBE的脉冲峰值更容易出现极大值,其最大值为5 118数字单位,而正极性NBE的脉冲峰值最大值为3 347数字单位。NBE的孤立性明显,分别有73.5%和78.5%的NBE在其发生后和发生前的1s内没有其他任何触发事件。正、负极性NBE的孤立性差异也较明显,4.39%的正极性NBE在其发生后的10ms内出现了其他放电过程,而负极性NBE对应的比例仅为1.61%。基于这些特点,并结合两者放电高度的差异,初步探讨了两者放电过程的一些差异。Using the multi-station electric field data from field test in summer of 2007,based on electrical waveforms of 148871 narrow bipolar events（NBEs） selected with a relatively loose criterion and with hand picking,characteristics of NBEs with opposite polarities comprising the pulse width,peak value of electric field and the isolation were analyzed.The result shows that waveforms of NBEs with opposite polarities have distinct differences.The average pulse widths of positive and negative NBEs are 6.42 μs and 5.46 μs,respectively,and the pulse width of positive NBEs has a higher chance to be extremely large,with the maximum of 19.76 μs.The average peak values of electric field of positive and negative NBEs are 403.4 and 627.0 digital units,respectively,while that of 97 713 negative return strokes is only 256.7 digital units.Peak electric field of negative NBEs has a higher chance to be extremely large,with the maximum of 5 118 digital units,while the maximum of peak electric field of positive NBEs is only 3 347 digital units.Most of NBEs are clearly isolated with other discharge processes.73.5% of NBEs occurred without any other discharge process occurring with in 1 s after them,and 78.5% of NBEs occurred without any discharge process occurring within 1 s before them.The difference of characteristic of isolation of opposite-polarity NBEs is also obvious.4.39% of positive NBEs occurred with other discharge processes occurring within 10 ms after them,while only 1.61% of negative NBEs occurred with other discharge processes occurring within 10 ms after them.Based on these differences and the difference of source height of opposite-polarity NBEs,differences in discharge processes of NBEs are preliminarily discussed.

关 键 词：双极性窄脉冲 电场波形 孤立性 

分 类 号：P427.32[天文地球—大气科学及气象学]