Whole Earth Mantle Conductivity

将使用新的和已经发表的响应函数对地幔电导率进行全面的研究。这项工作将汇集各种来源的响应函数进行组合解释，从而获得最佳的空间和频率覆盖。在数据较少的频段，pi将用从磁观测数据和很长周期MT数据估计的新响应函数来补充这些响应函数。在过去的几年中，地磁数据反演的各种新技术得到了发展，包括D+存在性算法、漏斗函数方法以及通过非线性反演问题的正则化找到光滑模型。pi将以系统的方式将这些应用于全球响应函数集合，以模拟整个地球的地幔电导率。正则化方法的扩展将使他们能够测试关于地幔电导率结构的各种假设；例如，670公里地震不连续处的电导率跳变是否与数据一致或符合数据要求？是否存在一个深度以下的横向非均质性在数据中是不需要的？这些问题的答案可能为了解地球内部的物理学提供有价值的见解。

A comprehensive study of mantle electrical conductivity will be carried out using both new and already published response functions. The work will bring together response functions for a variety of sources for combined interpretation, thereby obtaining the best possible spatial and frequency coverage. In the frequency bands where there are few data the PIs will supplement these response functions with new ones estimated from magnetic observatory data and from very long period MT data. Various new techniques for inverting geomagnetic data have been developed over the past few years, including the D+ existence algorithm, the funnel function approach, and the finding of smooth models through regularization of non-linear inverse problems. The PIs will apply these in a systematic way to the global response function collection to model mantle conductivity for the whole Earth. Extensions to the regularization approach will allow them to test various hypotheses about mantle conductivity structure; e.g. Is a jump in conductivity at the 670km seismic discontinuity consistent with or required by the data? Is there a depth below which lateral heterogeneity in conductivity is not required by the data? The answers to such questions may provide valuable insight into the physics of the Earth's interior.