| 中国中东部地区地震电离层低频电场扰动频段及背景时段选取分析 |
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| 引用本文： | 王亚璐,张学民,欧阳新艳,王晓,娄文宇,杜晓辉,董磊.中国中东部地区地震电离层低频电场扰动频段及背景时段选取分析[J].地球物理学报,2022,65(3):908-923. |
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| 作者姓名： | 王亚璐 张学民 欧阳新艳 王晓 娄文宇 杜晓辉 董磊 |
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| 作者单位： | 中国地震局地震预测研究所,北京 100036,中国地震台网中心,北京 100045 |
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| 基金项目： | 国家重点研发计划(2018YFC1503506);中国地震局地震预测研究所基本科研业务经费(2019IEF0503);the APSCO Earthquake Research Project PhaseⅡ;中国地震科学实验场项目(2018CSES0203)共同资助。 |
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| 摘 要： | 诸多卫星观测结果表明,地震前后电离层会出现宽频带电场扰动,而背景场时频段的合理选取是电离层电场扰动提取的基础.本研究遴选了地磁活动平静期(Dst>-30 nT,Kp<3)飞越中国中东部地区(29°N—39°N,107°E—117°E)长达6年共计1527轨DEMETER卫星数据,在电离层低频电场随频率和时间的变化特征分析基础上,对低频背景电场的频段和时段选取开展了研究.研究结果表明:频段选取方面,利用夜侧数据分析地震电离层异常时,可将200~2200 Hz划分为253~566 Hz、566~605 Hz和605~2200 Hz共3个频段,利用日侧数据分析地震电离层异常时,可划分为215~330 Hz、330~703 Hz、703~742 Hz和742~2200 Hz共4个频段,无论是日侧还是夜侧,高频端的数据方差均较大,因此提取电离层异常时需要设置较大的阈值,而低频端需要设置相对较小的阈值;背景时段选取方面,数据集标准差结果表明往年同月数据和分析时段前1个月数据做背景场的效果相当,就实时跟踪分析与地震有关的电离层电场扰动需要,可优先考虑使用邻期数据做背景场,而数据时段并非越长越好,在空间天气平静的情况下,可使用当日前1个月的数据做背景场.
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| 关 键 词： | DEMETER卫星 电离层低频电场 地震 频段 背景时段 |
Analysis on the frequency band and background time period of the ionosphere seismo-electric disturbances in central and eastern China |
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| WANG YaLu,ZHANG XueMin,OUYANG XinYan,WANG Xiao,LOU WenYu,DU XiaoHui,DONG Lei.Analysis on the frequency band and background time period of the ionosphere seismo-electric disturbances in central and eastern China[J].Chinese Journal of Geophysics,2022,65(3):908-923. |
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| Authors: | WANG YaLu ZHANG XueMin OUYANG XinYan WANG Xiao LOU WenYu DU XiaoHui DONG Lei |
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| Institution: | (Institute of Earthquake Forecasting,China Earthquake Administration,Beijing 100036,China;China Earthquake Networks Center,Beijing 100045,China) |
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| Abstract: | There are many researches based on satellite observation showing that the ionosphere electric field may be disturbed before and after earthquakes.The determination of the frequency band and the background time period is the basis of the extraction of seismo-ionosphere electric disturbances.In this paper,the total of 1527 DEMETER orbits during the quiet geomagnetic period(Dst>-30 nT,Kp<3)over central and eastern China(29°N—39°N,107°E—117°E)were screened out,then the study of the frequency band and time period of background electric field was carried out based on the analysis of the characteristics of ionospheric electric field varying with frequency and time.In terms of frequency band,the analysis results show that 200~2200 Hz can be divided into three frequency bands for nightside:253~566 Hz,566~605 Hz and 605~2200 Hz,while into four frequency bands for dayside:215~330 Hz,330~703 Hz,703~742 Hz and 742~2200 Hz.Regardless of the dayside or night-side,the variance of data at the high frequency band is relative larger,so a large threshold needs to be set when doing the extraction of the ionosphere disturbances,while a relatively smaller threshold needs for the low frequency band.In terms of time period,both the data of the same month in previous years and the one month before the current month could be used as the background field.The analysis of the standard deviation show that both methods work equally well,and the former is slightly superior.Given the need of doing real-time tracking analysis of the ionosphere disturbances,we could give priority to using the data of the one month before.And for the time span of the data,more is not always well.If the geomagnetic activity is quiet,it is better to use the data of only one month before as the background field. |
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| Keywords: | DEMETER satellite Ionosphere electric field Earthquake Frequency band The background time period |
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