Electrical conductivity of the suboceanic upper mantle constrained by satellite-derived tidal magnetic fields: three-dimensional inversion, validation and interpretation
SUMMARY We present the first 3-D upper-mantle conductivity models obtained by an inversion of the satellite-derived tidally induced magnetic fields (TIMFs). We primarily use the M$_2$ period, but the potential benefit of the O$_1$ period is also inspected. The inverse-problem solution is found using...
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Veröffentlicht in: | Geophysical journal international 2024-07, Vol.238 (3), p.1254-1268 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | SUMMARY
We present the first 3-D upper-mantle conductivity models obtained by an inversion of the satellite-derived tidally induced magnetic fields (TIMFs). We primarily use the M$_2$ period, but the potential benefit of the O$_1$ period is also inspected. The inverse-problem solution is found using the recently developed frequency-domain, spherical harmonic finite-element method based on the adjoint approach. We tested two different TIMF data sets derived from the satellite measurements of the Swarm mission and two different regularizations; the solution is either required to be sufficiently smooth or reasonably close to the a priori 3-D conductivity model WINTERC-e Wd-emax. The reconstructed conductivity models are locally compared with the 1-D conductivity profiles from other studies. If we use one of the available TIMF data sets, the smooth reconstructed model gravitates towards Wd-emax and the TIMF-adjusted Wd-emax model is closer to the reference conductivity profiles than the original Wd-emax model. Finally, we use the obtained 3-D conductivity distributions to calculate the corresponding 3-D water distribution in the upper mantle using thermodynamical and compositional models coupled to the electrical-conductivity laboratory measurement of individual mantle constituents. |
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ISSN: | 0956-540X 1365-246X |
DOI: | 10.1093/gji/ggae209 |