Refined techniques for data processing and two-dimensional inversion in magnetotelluric II:Which data polarization mode should be used in 2D inversion
Refined techniques for data processing and two-dimensional inversion in magnetotelluric II:Which data polarization mode should be used in 2D inversion
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发表时间：
2010
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通讯作者：
Cai Jun;Chen Xiao
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作者：
Cai Jun;Chen Xiao
针对大地电磁二维反演中TE、TM极化模式的选择问题,设计了多个二维、三维模型进行了正演计算,从数据对比和反演结果对比两方面入手,分析研究了三维模型和二维模型响应数据的差异、反演中极化模式的选择、以及三维模型数据的二维反演近似等问题.本文的研究分为两个部分：一是三维与二维响应的差异，二是二维反演结果的对比。结果表明，在3D场景中，TE模式下对近似2D结构的要求比TM模式下更严格。当三维效应较严重时，通过对三维数据进行二维反演，结果表明，仅使用TM模式数据的反演模型更有效，且模型中的体模结构比使用TE模式或TE + TM模式的要少。在TM模式下，相位畸变小于视电阻率，因此可以提高反演时相位的权重。对于野外资料的二维反演，首选仅TM模式，其次是TE + TM模式，不推荐仅TE模式。
Aiming at the choice of data polarization mode in magnetotelluric 2D inversion, several 2D and 3D models are designed to study the difference between 3D response and 2D response, the choice of data polarization mode in 2D inversion, and 2D approximate interpretation of 3D data. The research is divided into two parts: one is the difference between 3D and 2D response, and the other is comparison of 2D inversion results. The results manifest that in the 3D scenario the demand for approximate 2D structure in TE mode is much stricter than in TM mode. When 3D effect is relatively severe, by applying 2D inversion to 3D data, the results show that the inversion model using only TM mode data is more valid, and the phantom structures are less than using TE mode or TE + TM mode. In TM mode, the distortion of phase is less than apparent resistivity, so the weight of phase in inversion can be increased. For 2D inversion of field data, TM mode only is the first choice, next is TE + TM, TE mode only is not proposed.