天祝台阵地电场季节变化及其两种影响因素分析

doi:10.12196/j.issn.1000-3274.2020.04.013

摘要/Abstract

摘要： 地电场是联系空间Sq电流体系、地球表面电流和内部电流活动的地球物理量, 它包含了空间电流系变化产生的大地电(流)场和区域环境变化等引起的自然电场。通过研究青藏高原东北缘的天祝台阵5个固定地电场台站连续10年观测数据, 得出该区域地电场变化具有明显的366±(<1) d周期。且大地电流矢量方向有明显的季节变化, 每半年改变一次方向, 方向变化时间一般为每年4月和9~10月; 大地电流矢量的强度变化也具有周期性。通过建立简单模型进行定量化分析, 认为地电场季节变化主要受到Sq年变和区域气候环境的耦合作用, 主要依据为地电场长趋势变化与电离层Sq电流年变化趋势吻合。基于区域性气候、冻融深度等季节性变化模型开展计算, 认为气温导致了地下浅层介质电性结构、电极附近电位方向的变化, 影响了地电场的长趋势变化。本文结果有助于认识超低频地电场年变周期特点及其原因, 并探索其应用前景。

关键词: Sq电流, 天祝台阵, 地电场, 气候环境, 季节变化

Abstract: Geoelectric field is a key factor to make a connection between the space, the surface and interior of the Earth. It includes the induced currents due to the change of the space current system, and the conduction current caused by material migration in the deep earth. Based on the processing and analysis of the 10-years observation data from five fixed stations of Tianzhu Array in the northeastern margin of the Qinghai-Tibet Plateau, it is concluded that the telluric current in this area has an obvious annual variation with a period of 366 ±(<1) days, and its direction also has obvious seasonal variation characteristics. The telluric current direction changes once every 6 months, the time node of the direction change is April and September/October every year. We develop a semi-quantitative model, based on the following two results: ① the long-term trend of the telluric current is consistent with the annual trend of ionospheric Sq current; ② by calculating, it is found that the factors, the periodic change of regional climate, can lead to the structure change of surface electrical and further affect the seasonal trend of telluric current. These results expand the understanding of the annual ultra-low frequency telluric current and the knowledge and potential applications of the natural electromagnetic field.

Key words: Sq current, Tianzhu array, Telluric current, Climate and environment, Seasonal variation

中图分类号:

P319.1

章鑫, 孙君嵩, 钱银苹, 刘君. 天祝台阵地电场季节变化及其两种影响因素分析[J]. 地震, 2020, 40(4): 169-182.

ZHANG Xin, SUN Jun-song, QIAN Yin-ping, LIU Jun. Seasonal Variation of Geoelectric Field in Tianzhu Array and Its Influence of Two Factors[J]. EARTHQUAKE, 2020, 40(4): 169-182.

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