新沂台和马陵山台地电场日变化及潮汐响应初步分析

基于江苏省新沂台和山东省马陵山台同(近)场地观测的地磁场、地电场和分量应变观测数据，详细分析了两台站地电场日变化的波形、变幅、相位和优势周期成分以及日变幅的季节效应和台址电性条件对其的影响，并在此基础上分析了地电场日变化的机理.结果显示:① 两台站地电场日变化主要为两次起伏变化，主相起伏集中在当地午前午后时段，且起伏波形与磁场日变化的起伏波形大致相同，存在相位差，但主相起伏时段与磁场对时间的偏导曲线上的日变化起伏时段大致对应；地电场变化与磁场正交分量的变化显著相关，且与同方向的分量应变显著相关；地电场日变化波形与分量应变日变波形有很大差异；② 两台站地电场、地磁场日变化的优势周期为12 h，8 h，24 h，最显著周期为12 h，其中12 h和24 h周期成分是应变分量的优势周期；③ 两台站同方向地电场日变化的波形高度相似，但同台正交分量之间的日变幅有方向性差异；朔望月时段的日变幅大于上下弦月时段，日变幅有夏季大于冬季的季节效应；台址电导率越低，日变幅越大.地电场日变化既表现为广域性特征，又表现为局部性特征.地电场日变化机理分析认为，地电场日变化是由月日潮汐力和太阳风引起的电离层活动所导致，同时还受到季节、台址电性条件等多因素的影响. 

Diurnal variation of geoelectric field and its tidal response for the stations Xinyi and Malingshan

This paper analyzes the waveform, amplitude, phase, and dominant period of the diurnal variation of geoelectric field observed at the two stations Xinyi of Jiangsu and Malingshan of Shandong, associated with the observation data of the geomagnetic field and geostrain in/near the two stations, and then discussed seasonal effect of diurnal variation amplitude and the effects from the electrical conditions of station site. Furthermore, the mechanism of the diurnal variation is explored. The results showed that the diurnal variation of geoelectric field appear as two obvious undulating changes, in which its main phases generally appear in the time interval close to noon (local time), and the fluctuation of the main phase is approximately the same as that of the diurnal variation of the geomagnetic field, but there is an phase difference between them. However, the fluctuation time of the main phase roughly corresponds to that of the diurnal fluctuation on the partial derivative curves of the geomagnetic field in respect to time. There are significant correlations between the orthogonal components of both the geoelectric field and geomagnetic filed and between the geoelectric field component and parallel geostrain one, although the diurnal variation of geoelectric field is largely different from the diurnal variation of the geostrain. It can also be concluded that the predominant periodic components of the diurnal variations of both geoelectric and geomagnetic fields chiefly are 12 h, 8 h and 24 h, in which the most principal period is 12 h, and the 12 h-and 24 h-period component are just the dominant periods of the two orthogonal components of geostrain. The fluctuations of the diurnal variation of geoelectric field along the same direction is nearly identical for the two stations. However, the range of the diurnal variation between the two orthogonal components of the same station is different in directivity. The range in the lunar new and full moon days is larger than that in the first and last quarter moons, and the range is also larger in the summer than in the winter, which is obviously a seasonal effect. The smaller the conductivity of the underground medium is, the more larger the range is. The above-mentioned appearances of the diurnal variation of geoelectric field at the two stations have both the wide-area and local characteristics. In the end, it is believed that the diurnal variation of geoelectric field is caused by the force from the solar and lunar tides as well as the ionospheric activity induced by the solar wind, and it is also affected by other factors such as the season and electrical conditions of underground medium of station site, etc.