依据FFT计算方法，选取中国地磁、地电台网各10个台站记录，对NS、EW分量进行10日频谱分析，结果发现，磁静日和磁扰日电、磁场数据具有不同特征。
（1）磁静日数据：①电、磁场周期成分以12 h为主，其次为24 h、8 h。在X分量（NS向）中，非显著周期成分，如4 h、48 h、6 h，所占频次较大，Y分量只存在12 h、24 h、8 h成分；②EW测向（或Y分量）电、磁场最大频谱值大于NS测向（X分量）；③ X分量最大谱值多在12 h，Y分量在24 h；④台网位置由北向南，Y分量最大谱值逐渐减小，X分量则两头略高，在35.0°—40.0°N范围内变化平稳。
（2）地电暴日数据：①沿海地区NS测向主要周期成分比内陆地区复杂且偏大，大于18 h的成分相对活跃，最大以20 h、24 h、36 h成分出现，内陆地区最大周期成分为18 h，其次为12 h。EW测向谱值在各台变化较一致，均体现了以12 h、8 h为主的变化特征；②各台NS测向最高谱值均大于EW测向。
According to the FFT calculation method, 10 stations record of China geomagnetic and 10 geoelectric networks are selected to perform 10-day spectrum analysis on NS and EW components. It was found that there are different characteristics with the magnetic static day, magnetic disturbance solar energy and magnetic field data.
(1)Magnetic static day data:①The electrical and magnetic field periodic components are mainly 12 h, secondarily followed by 24 h and 8 h. In the X component (NS direction), non-significant periodic components occupy a larger frequency, such as 4 h, 48 h and 6 h and the Y component only has 12 h, 24 h and 8 h components; ②The maximum spectral value of electricity and magnetic fields of EW direction finding (or Y component) is larger than NS direction finding (X component); ③The maximum spectral value of the X component is mostly at 12 h, and the Y component is at 24 h;④The position of the four networks is from north to south, and the maximum spectral value of the Y component is gradually reduced. The X component is slightly higher at both ends, and the variation is stable within the range of 35.0°-40.0°N.
(2)Magnetic storm day data:①The main periodic components of the X component in the coastal area are more complex and larger than those in the inland area. The components above 18 h are relatively active, with the largest components appearing at 20 h, 24 h and 36 h. The maximum period component of the inland region is 18 h, next followed by 12 h. The Y component spectral values are more consistent in each station, and both reflect the variation characteristics of 12 h and 8 h;②The highest spectral values of each X component in every station are larger than the Y component.
2019,40(2): 52-61 收稿日期：2018-08-24
DOI：10.3969/j.issn.1003-3246.2019.02.007
基金项目：中国地震局“三结合”课题（项目编号：3JH-160309，3JH-201901023）
作者简介：周剑青(1977-),男,工程师,主要从事地震电磁监测工作
*通讯作者：郭建芳(1977-),女,高级工程师,从事地震分析预报工作
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