北京地区的地闪分布及回击峰值电流强度特征

The Distribution Characteristics and Return Stroke Peak Current of CG Lightning in Beijing Regions

针对北京地区开展闪电探测研究,分析闪电分布特征及回击峰值电流强度,不仅能够深入了解北京地区闪电活动规律,而且对重点区域的雷电灾害防护提供实际的参考价值。利用BLNet 2015-2017年的闪电定位资料和闪电快电场变化资料,基于传输线模式对雷电流进行反演估算,统计分析了北京地区的地闪分布及回击峰值电流强度特征。分析结果表明:北京地区闪电发生频次最高的时段为20:00-23:00,地闪约占总闪的25.1%,其中正地闪约占总地闪的21.1%。正地闪回击峰值电流强度算术平均值为25.2 kA,几何平均值为15.2 kA,负地闪回击峰值电流强度算术平均值为14.2 kA,几何平均值为9.9 kA;正、负地闪首次回击峰值电流强度算术平均值为17.6 kA,几何平均值为13.2 kA,正地闪首次回击峰值电流强度算术平均值为27.0 kA,几何平均值为17.7 kA,负地闪首次回击峰值电流强度算术平均值为15.1 kA,几何平均值为12.2 kA;正地闪继后回击峰值电流强度算术平均值为22.2 kA,几何平均值为11.8 kA,负地闪继后回击峰值电流强度算术平均值为13.2 kA,几何平均值为9.6 kA;对地闪首次回击和继后回击峰值电流强度进行统计分析,发现有37.5%多回击地闪至少有一次继后回击峰值电流强度大于首次回击峰值电流强度,地闪继后回击峰值电流强度大于首次回击峰值电流强度的继后回击数占总的继后回击数的24.7%;峰值电流强度绝对值>100 kA的地闪主要分布在北京东部、东北部、西部、北部的山区以及北京城区。

Research on lightning detection in Beijing regions,analysis of lightning intensity and spatial and temporal distribution characteristics,it not only can understand the activity laws of lightning in Beijing regions,but also provide practical reference value for lightning protection in key area.The paper using the data of lightning fast electric field change collected by Beijing lightning network(BLNet) in Beijing regions during 2015-2017,based on transmission line mode to estimate lightning current,and analyze the distribution characteristics and return stroke peak current of CG lightning in Beijing regions.Analysis results indicate that 20:00-23:00 was the highest frequency of lightning occurrence in Beijing regions,the CG lightning was about 25.1% of the total lightning,and the positive CG lightning was about 21.1% of the total CG lightning.The positive CG lightning return-stroke average peak current intensity arithmetic mean was 25.2 kA,geometric mean was 15.2 kA,and the negative CG lightning return-stroke average peak current intensity arithmetic mean was 14.2 kA,geometric mean was 9.6 kA,and the CG lightning average peak current absolute value arithmetic mean was 17.6 kA,geometric mean was 13.2 kA;the positive CG lightning first return-stroke average peak current intensity arithmetic mean value was 27.0 kA,geometric mean was 17.7 kA,the negative CG lightning first return-stroke average peak current intensity arithmetic mean value was 15.1 kA,geometric mean was 12.2 kA;and the positive CG subsequent return-stroke average peak current intensity arithmetic mean value was 22.2 kA,geometric mean was 11.8 kA;and the negative CG subsequent return-stroke average peak current intensity arithmetic mean value was13.2 kA,and geometric mean was 9.6 kA;analyzed the CG lightning peak current characteristics of the first return stroke and subsequent return stroke,found that the return stroke peak current of 37.5% multiple return stroke CG lightning at least one subsequent return peak current intensity is greater than the first return stroke,at the same time,it is also found the number of subsequent return stroke CG lightning peak current intensity is greater than first return stroke was about 24.7% of the total number of CG lightning return stroke.The stronger CG lightning,that lightning peak current intensity in the range of >100 kA,it is mainly distributed in the mountains of eastern,northeast,western and northern of Beijing and urban area.