闪电定位资料质量控制中小幅值地闪范围的研究

Study of the Small Amplitude Cloud-to-ground Lightning Data in Quality Control of Lightning Location System

分析和应用闪电定位资料必须对其数据进行质量控制,如将被闪电定位仪误探为地闪的云闪小幅值数据剔除。为此,采用对数正态分布函数拟合分析了重庆地区闪电定位资料(1999—2008年),发现剔除幅值为5 kA以下的地闪(占总地闪数比例为1.05%),能更好地反映地闪的统计特征,且能通过显著性检验;分析了不同幅值小电流地闪频次的逐年变化特征,发现剔除5 kA以下的地闪,既能反映闪电定位仪的工作原理(存在误探现象),也能客观反映设备升级优化后取得的效果(误探明显减少)。基于此,建议将重庆地区"小幅值"地闪范围定为雷电流幅值在5 kA以下的地闪,该结论可供各地区研究"小幅值"地闪范围和质量控制提供参考。

To analyze and use the data of lightning location system （LLS）, it is necessary to perform quality control of the data, for example, excluding some small amplitude cloud-to-cloud lightning which is inevitably mistaken to cloud-to-ground lightning （CG） by LLS. Using the lognormal distribution function, we performed fitting and analysis of the data obtained by a lightning location system in Chongqing, China from 1999 to 2008. It is found that by ignoring the data of lightning with amplitudes less than 5 kA （which occupies 1.05% of the total data）, we obtained the best fitting re- sult that passes the test of statistical significance and reflects the statistical characteristic of CG. We also analyzed the variation of frequency distribution and proportion of different region of small amplitude CG~ and found that ignoring the CG data blow 5 kA not only accords with the error feature of LLS, but also reflects the effect of upgrading LLS devices in decreasing deviation. Therefore, we delimit the ＂small amplitude＂ of lightning in Chongqing as below 5 kA. The result could be referred by researches of＂small amplitude＂ lightning and quality control LLS data for other geographic regions.