摘要
大地电磁测深采集的是天然电磁场,具有振幅微弱、频带宽的特点.在人文活动密集地区,电磁噪声干扰日趋严重,导致大地电磁测深曲线具有明显的近场源效应.本文利用电偶极子理论模型分析了电磁相关噪声对大地电磁测深数据的影响特征,并对湖南衡阳某矿区噪声实验数据进行了讨论,分析了矿区噪声的特点.分别利用远参考方法和基于大地电磁时间序列依赖关系的去噪方法对实验数据进行了处理.研究结果表明:矿区近场源噪声的频率一般大于0.1 Hz,远参考方法可以压制高频部分近场源噪声,但在0.1 Hz附近仍存在跳点;基于大地电磁时间序列依赖关系的去噪方法也可以压制矿区强相关噪声,抑制近场源效应,其效果要好于远参考的处理;两种方法结合可以更好的压制强噪声,基本消除了近场源效应,有效提高了大地电磁测深数据的信噪比.
Natural variant electromagnetic（ EM） signal is normally weak and has a broad frequency band,serious noise especially in areas of intense human activity results in near-field source effect of some bands or even the whole frequency band. In this paper,we introduce the electric dipole theoretical model to analyze the noise characteristics of magnetotelluric（ MT） sounding data,and analyze the characteristics of mining noise of MT experimental data collected at neighbor of a mine in Hengyang city of Hunan. Finally,Using the de-noisng mothed based on the relationship of MT time series（ removing noise of MT by the relationship of time series,RNMTRTS） to process the experimental data. The results showed that the frequency of mine near field source is generally higher than0. 1 Hz. Remote reference method（ RR） can suppress the high frequency part of the near-field source noise, but still contains outliers near the frequency of 0. 1 Hz; RNMTRTS can effectively remove strong related noise and suppress the effects of near-field source,and better than RR. Combining both methods can better suppress strong noise,and basically eliminate the near-field source effect,improve the quality of MT sounding data.
出处
《地球物理学进展》
CSCD
北大核心
2016年第3期1358-1366,共9页
Progress in Geophysics
基金
中国矿业大学(北京)煤炭资源与安全开采国家重点实验室大学生科技创新计划项目(SKLCRSM16DC10)
中国矿业大学(北京)中央高校基本科研业务费(2015QD03)
北京市大学生科学研究与创业行动计划项目
国家自然科学基金项目(51574250)
"深部探测技术与实验研究"专项课题(Sinoprobe-01
Sino Probe-01-02
Sino Probe-02-04)联合资助
关键词
大地电磁测深
近场源噪声
时间序列
去噪
magnetotellurics
near-field source noise
time series
remove noise
