Joint inversion of full-waveform GPR and ER data enhanced by the envelope transform and cross-gradients
Joint inversion of full-waveform GPR and ER data enhanced by the envelope transform and cross-gradients
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DOI：
10.1190/gpr2020-087.1
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发表时间：
2020-11
期刊：
影响因子：
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通讯作者：
D. Domenzain;J. Bradford;J. Mead
中科院分区：
文献类型：
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作者：
D. Domenzain;J. Bradford;J. Mead
提出了一种全波形探地雷达（GPR）和电阻率（ER）数据联合反演的算法。探地雷达通过反射率和速度对介电常数敏感，通过反射率和衰减对电导率敏感。ER对电导率直接敏感。这两种类型的数据通过麦克斯韦方程内在地联系在一起，我们共同反演它们。结果表明，这两种类型的数据协同工作，有效地规范对方，同时尊重物理的地球物理方法。我们首先计算灵敏度更新分别为GPR和ER数据使用伴随方法，然后我们总结这些更新，以考虑这两种类型的敏感性。灵敏度是通过让两种数据类型总是对我们的反演做出贡献的范例来添加的，该范例与它们各自的目标函数在每次迭代中被解决的程度成比例。我们的算法不假设地下几何形状，也不假设参数之间的结构相似性，需要一个良好的初始模型。我们发现，我们的联合反演优于GPR和ER单独反演，并确定GPR有效地支持ER在低电导率的地区，而ER支持GPR在强衰减的地区。
We develop an algorithm for joint inversion of full-waveform ground-penetrating radar (GPR) and electrical resistivity (ER) data. GPR is sensitive to electrical permittivity through reflectivity and velocity, and electrical conductivity through reflectivity and attenuation. ER is directly sensitive to electrical conductivity. The two types of data are inherently linked through Maxwell’s equations and we jointly invert them. Results show that the two types of data work cooperatively to effectively regularize each other while honoring the physics of the geophysical methods. We first compute sensitivity updates separately for both the GPR and ER data using the adjoint method, and then we sum these updates to account for both types of sensitivities. The sensitivities are added with the paradigm of letting both data types always contribute to our inversion in proportion to how well their respective objective functions are being resolved in each iteration. Our algorithm makes no assumption of the subsurface geometry nor structural similarities between parameters with the caveat of needing a good initial model. We find that our joint inversion outperforms both GPR and ER separate inversions and determine that GPR effectively supports ER in regions of low conductivity while ER supports GPR in regions with strong attenuation.