大地电磁阻抗估计方法对比

汤井田，张 弛，肖 晓，刘 祥

(中南大学 地球科学与信息物理学院 有色金属成矿预测教育部重点实验室，长沙 410083)

摘 要：比较了几种大地电磁阻抗估计方法的性能。为了给阻抗估计结果提供对照标准，首先介绍大地电磁模拟数据的生成方法，并从含噪数据中提取典型的噪声时间序列；然后介绍最小二乘估计、M回归估计、有界影响估计和重复中值估计这4种回归方法的基本原理，并用一组标准数据测试了它们的性能；最后采用4种估计方法处理不同程度加噪的模拟数据，与模拟结果进行比较。结果表明：重复中值估计的稳健性最优；当磁道存在噪声时，有界影响估计给出了明显优于M回归估计的结果，也能满足要求。因此，在实测数据处理中，推荐使用重复中值估计方法与有界影响估计方法。

关键词：大地电磁；稳健阻抗估计；M回归估计；有界影响估计；重复中值估计

Comparison of methods for magnetotelluric impedance estimation

TANG Jing-tian, ZHANG Chi, XIAO xiao, LIU xiang

(Key Laboratory of Metallogenic Prediction of Nonferrous Metals, Ministry of Education,
School of Geoscience and Info-Physics, Central South University, Changsha 410083, China)

Abstract:The performances of different kinds of methods for magnetotelluric impedance estimation were compared. The method of generating magnetotelluric simulated data was introduced, the typical noise series was extracted from noisy data. The basic principles of four regression methods of least square estimator, M-regression estimator, bounded influence estimator and repeated median estimator were introduced. These methods were tested using a set of standard data. At last, simulated data added by noise at different levels were processed by the four different estimators and compared with the simulated results. The results show that the repeated median estimator is the most robust. When the noise exists in the magnetic channel, the results estimated by the bounded influence method are acceptable, which are more stable than those estimated by the M-regression method. So, in the magnetotelluric data processing, the repeated median method and bounded influence method are recommended.

Key words:magnetotelluric; robust estimation; M-regression estimation; bounded influence estimation; repeated median estimation