地电暴事件判别方法及特征分析

Discrimination Method and Characteristic Analysis of Geoelectric Storms

本文基于我国2015—2018年间地电暴事件,通过对筛选的数据曲线变化特征归纳分析,总结出以下快速准确判断地电暴事件的依据:(1)地电暴发生时,会压制地电场六道观测数据正常日变形态,且变幅是正常日变幅值2倍以上或更大;(2)地电暴事件具有广域同步性,可通过多台观测数据对比判断;(3)地电暴和地磁暴具有同源性,可通过地磁观测来判断;(4)经过上述初判后,还应排除观测系统、自然环境、人为干扰、场地环境事件影响,才能确认为单一地电暴事件。通过对地电暴波形特征的分析,发现一般情况下地电暴变幅与地磁磁情指数—K指数呈正比关系,但是同一台站地电暴变幅在同一K指数下差异较大。不同台站对同一地电暴事件幅度响应不同,仅从变幅来看纬度效应不明显,有局部区域性特点,可能与台站台址条件\,地电场布极方式方位等因素均有关。

In this study,we consider the geoelectric storm events that occurred from 2015 to 2018 in China and identify the bases for quickly and accurately judging such phenomena by summarizing and analyzing the variation characteristics of screened data:(1)When a geoelectric storm occurs,the observation data of a geoelectric field are suppressed and the variation amplitude becomes more than twice the normal diurnal variation value.(2)Geoelectric storm events have a wide-area synchronicity,which can be judged by comparing the observation data of several stations.(3)A geomagnetic storm and geoelectric storm have homology,and the former can be judged by geomagnetic observations.(4)After the initial judgment,the influence of the observation system,natural environment,human interference,and environmental events should also be excluded before a geoelectric storm event is affirmed.The analysis results of the waveform characteristics of a geoelectric storm show that its amplitude is generally proportional to the K index,but the amplitude of a geoelectric storm at the same station greatly varies under the same K index.Under the same geoelectric storm,different stations have different amplitude responses,and the latitude effect is unclear,so it has regional characteristics.These characteristics may be related to the geological conditions of a station,the electrode distribution of a geoelectric field,and other factors.