Speaker
Description
The interaction of the oceanic tidal flows with the Earth's main magnetic field provides a powerful natural source of electromagnetic energy suitable for sub-oceanic upper-mantle electrical conductivity sounding. We have developed a new frequency-domain, spherical harmonic-finite element approach to the inverse problem of global electromagnetic (EM) induction. It is set up for an effective inversion of satellite-observed tidally-induced magnetic field in terms of three-dimensional structure of the electrical conductivity in the sub-oceanic upper mantle. The numerical code is parallelized using the OpenMP standard and it uses either the Math Kernel Library (MKL) or AMD Optimizing CPU Libraries (AOCL) to compute the Fourier transform effectively.
In order to demonstrate that the new approach can successfully reconstruct the 3-D upper mantle conductivity, we performed synthetic tests using a 3-D conductivity model WINTERC-E (Fullea et al., 2021) as a testbed. The WINTERC-E model is independent of any EM data and thus it represents an ideal target for synthetic tests of the 3-D EM inversion. In the next step, we proceed to the inversion of satellite-derived (Swarm) models of tidal magnetic signatures. We explore different datasets and different regularization settings in the inversion.
