| DEMETER卫星观测的超低频电场扰动 预处理方法及震例应用分析 |
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| 引用本文： | 欧阳新艳,申旭辉.DEMETER卫星观测的超低频电场扰动 预处理方法及震例应用分析[J].地震学报,2015,37(5):820-829. |
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| 作者姓名： | 欧阳新艳 申旭辉 |
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| 作者单位： | 1.中国北京 100036 中国地震局地震预测研究所 |
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| 基金项目： | 中国地震局地震预测研究所基本科研业务费专项2014IES010203中国地震局地震预测研究所基本科研业务费专项2015IES0405中国地震局地震预测研究所基本科研业务费专项2012IES0401国家自然科学基金41404126 |
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| 摘 要： | 基于法国DEMETER卫星观测的超低频(ULF)电场波形， 本文提出了更简单易实施的ULF电场扰动预处理方法. 利用该方法， 对文献中已报道的2010年2月27日智利MS8.8地震前的ULF电场扰动进行了更全面的分析. 结果表明: 已报道的20°S—40°S地磁纬度带内的ULF电场扰动并非仅出现在最靠近震中的半轨道， 而是出现在较大的经度范围内. 大范围ULF电场扰动的区域正好位于南大西洋异常区， 很可能受到该区域异常磁场的影响. 南大西洋异常中心区域的ULF电场扰动表现出共轭特征， 即在南北地磁纬度20°—40°范围内ULF电场均出现约5 mV/m的扰动， 北纬地区的ULF电场扰动幅度相比南纬地区更小. 而在南大西洋异常中心区域外的ULF电场扰动则仅在20°S—40°S地磁纬度带内出现， 在其共轭区并未观测到ULF电场扰动. 这可能是由于南大西洋异常中心区域外的ULF电场扰动幅度比中心区域更小所致， 在电离层中由于碰撞效应更易被衰减， 因此ULF电场扰动无法传播至其共轭区. 本文的方法和结果可为后续更全面地分析卫星在电离层高度记录的ULF电场扰动提供参考.
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| 关 键 词： | DEMETER卫星 超低频(ULF)电场扰动 南大西洋异常区 |
| 收稿时间： | 2015-04-14 |
A method for pre-processing ULF eIectric fieId disturbances observed by DEMETER and its case appIication anaIysis |
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| Affiliation: | 1.Institute of Earthquake Science， China Earthquake Administration， Beijing 100036， China2.School of Earth and Space Sciences， Peking University， Beijing 100871， China3.Institute of Crustal Dynamics， China Earthquake Administration， Beijing 100085， China |
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| Abstract: | This paper presents a method for pre-processing ULF electric field disturbances based on ULF waveforms observed by French DEMETER satellite. This method is simpler and easier to carry out. We analyze comprehensively ULF disturbances before the Chile MS8.8 earthquake on 27 February 2010， which have been reported in the literature， by using our method. The results show that reported ULF disturbances in 20°S—40°S geomagnetic latitude bands do not just appear on the half-orbit that is the closest to the epicenter， but ULF disturbances are observed in a wider longitude range. The large range with ULF disturbances is located in the region of South Atlantic anomaly (SAA)， and ULF disturbances may be affected by the geomagnetic field anomaly in this region. ULF disturbances in the center of SAA region show a conjugate distribution， i.e.， electric field fluctuates with the amplitude of 5 mV/m at 20°—40° north and south geomagnetic latitudes. The amplitude of ULF disturbances at northern latitudes is weaker than those at southern latitudes. However， ULF disturbances outside the center of SAA region are only observed at 20°S—40°S geomagnetic latitudes， and there are no ULF fluctuations in the conjugate region. As ULF fluctuations outside the center of SAA region with the weaker amplitude are easier to be attenuated because of collision effects in the ionosphere， ULF disturbance cannot propagate to the conjugate region. The method and results in this paper can provide references for subsequently thorough analyses on ULF fluctuations recorded by satellites in the ionosphere. |
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