Sensitivity analysis of the lithospheric magnetic field at satellite altitude: the effects of the inducing field and the shape of the magnetic lithosphere
As a means of quantitative interpretation, forward calculations of the global lithospheric magnetic field in the Spherical Harmonic (SH) domain have been widely used to reveal geophysical, lithological, and geothermal variations in the lithosphere. Traditional approaches either do not consider the n...
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Science Press
2025-05-01
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| Series: | Earth and Planetary Physics |
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| Online Access: | http://www.eppcgs.org/article/doi/10.26464/epp2025037?pageType=en |
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| author | JinSong Du YuKun Li HouPu Li ChangQing Yuan KangAn Zhao JiangSong Gui Pan Zhang ShaoFeng Bian |
| author_facet | JinSong Du YuKun Li HouPu Li ChangQing Yuan KangAn Zhao JiangSong Gui Pan Zhang ShaoFeng Bian |
| author_sort | JinSong Du |
| collection | DOAJ |
| description | As a means of quantitative interpretation, forward calculations of the global lithospheric magnetic field in the Spherical Harmonic (SH) domain have been widely used to reveal geophysical, lithological, and geothermal variations in the lithosphere. Traditional approaches either do not consider the non-axial dipolar terms of the inducing field and its radial variation or do so by means of complicated formulae. Moreover, existing methods treat the magnetic lithosphere either as an infinitesimally thin layer or as a radially uniform spherical shell of constant thickness. Here, we present alternative forward formulae that account for an arbitrarily high maximum degree of the inducing field and for a magnetic lithosphere of variable thickness. Our simulations based on these formulae suggest that the satellite magnetic anomaly field is sensitive to the non-axial dipolar terms of the inducing field but not to its radial variation. Therefore, in forward and inverse calculations of satellite magnetic anomaly data, the non-axial dipolar terms of the inducing field should not be ignored. Furthermore, our results show that the satellite magnetic anomaly field is sensitive to variability in the lateral thickness of the magnetized shell. In particular, we show that for a given vertically integrated susceptibility distribution, underestimating the thickness of the magnetic layer overestimates the induced magnetic field. This discovery bridges the greatest part of the alleged gap between the susceptibility values measured from rock samples and the susceptibility values required to match the observed magnetic field signal. We expect the formulae and conclusions of this study to be a valuable tool for the quantitative interpretation of the Earth’s global lithospheric magnetic field, through an inverse or forward modelling approach. |
| format | Article |
| id | doaj-art-4d3514db116e4cbe836a1e8dbda39295 |
| institution | OA Journals |
| issn | 2096-3955 |
| language | English |
| publishDate | 2025-05-01 |
| publisher | Science Press |
| record_format | Article |
| series | Earth and Planetary Physics |
| spelling | doaj-art-4d3514db116e4cbe836a1e8dbda392952025-08-20T02:19:16ZengScience PressEarth and Planetary Physics2096-39552025-05-019364265210.26464/epp2025037S22592-dujinsong-FSensitivity analysis of the lithospheric magnetic field at satellite altitude: the effects of the inducing field and the shape of the magnetic lithosphereJinSong Du0YuKun Li1HouPu Li2ChangQing Yuan3KangAn Zhao4JiangSong Gui5Pan Zhang6ShaoFeng Bian7Hubei Subsurface Multi-scale Imaging Key Laboratory, School of Geophysics and Geomatics, China University of Geosciences, Wuhan 430074, ChinaHubei Subsurface Multi-scale Imaging Key Laboratory, School of Geophysics and Geomatics, China University of Geosciences, Wuhan 430074, ChinaCollege of Electrical Engineering, Naval University of Engineering, Wuhan 430033, ChinaHubei Subsurface Multi-scale Imaging Key Laboratory, School of Geophysics and Geomatics, China University of Geosciences, Wuhan 430074, ChinaHubei Subsurface Multi-scale Imaging Key Laboratory, School of Geophysics and Geomatics, China University of Geosciences, Wuhan 430074, ChinaHubei Subsurface Multi-scale Imaging Key Laboratory, School of Geophysics and Geomatics, China University of Geosciences, Wuhan 430074, ChinaHubei Subsurface Multi-scale Imaging Key Laboratory, School of Geophysics and Geomatics, China University of Geosciences, Wuhan 430074, ChinaCollege of Electrical Engineering, Naval University of Engineering, Wuhan 430033, ChinaAs a means of quantitative interpretation, forward calculations of the global lithospheric magnetic field in the Spherical Harmonic (SH) domain have been widely used to reveal geophysical, lithological, and geothermal variations in the lithosphere. Traditional approaches either do not consider the non-axial dipolar terms of the inducing field and its radial variation or do so by means of complicated formulae. Moreover, existing methods treat the magnetic lithosphere either as an infinitesimally thin layer or as a radially uniform spherical shell of constant thickness. Here, we present alternative forward formulae that account for an arbitrarily high maximum degree of the inducing field and for a magnetic lithosphere of variable thickness. Our simulations based on these formulae suggest that the satellite magnetic anomaly field is sensitive to the non-axial dipolar terms of the inducing field but not to its radial variation. Therefore, in forward and inverse calculations of satellite magnetic anomaly data, the non-axial dipolar terms of the inducing field should not be ignored. Furthermore, our results show that the satellite magnetic anomaly field is sensitive to variability in the lateral thickness of the magnetized shell. In particular, we show that for a given vertically integrated susceptibility distribution, underestimating the thickness of the magnetic layer overestimates the induced magnetic field. This discovery bridges the greatest part of the alleged gap between the susceptibility values measured from rock samples and the susceptibility values required to match the observed magnetic field signal. We expect the formulae and conclusions of this study to be a valuable tool for the quantitative interpretation of the Earth’s global lithospheric magnetic field, through an inverse or forward modelling approach.http://www.eppcgs.org/article/doi/10.26464/epp2025037?pageType=enlithospheric magnetic fieldforward calculationspherical harmonic analysissensitivity analysissatellite magnetism |
| spellingShingle | JinSong Du YuKun Li HouPu Li ChangQing Yuan KangAn Zhao JiangSong Gui Pan Zhang ShaoFeng Bian Sensitivity analysis of the lithospheric magnetic field at satellite altitude: the effects of the inducing field and the shape of the magnetic lithosphere Earth and Planetary Physics lithospheric magnetic field forward calculation spherical harmonic analysis sensitivity analysis satellite magnetism |
| title | Sensitivity analysis of the lithospheric magnetic field at satellite altitude: the effects of the inducing field and the shape of the magnetic lithosphere |
| title_full | Sensitivity analysis of the lithospheric magnetic field at satellite altitude: the effects of the inducing field and the shape of the magnetic lithosphere |
| title_fullStr | Sensitivity analysis of the lithospheric magnetic field at satellite altitude: the effects of the inducing field and the shape of the magnetic lithosphere |
| title_full_unstemmed | Sensitivity analysis of the lithospheric magnetic field at satellite altitude: the effects of the inducing field and the shape of the magnetic lithosphere |
| title_short | Sensitivity analysis of the lithospheric magnetic field at satellite altitude: the effects of the inducing field and the shape of the magnetic lithosphere |
| title_sort | sensitivity analysis of the lithospheric magnetic field at satellite altitude the effects of the inducing field and the shape of the magnetic lithosphere |
| topic | lithospheric magnetic field forward calculation spherical harmonic analysis sensitivity analysis satellite magnetism |
| url | http://www.eppcgs.org/article/doi/10.26464/epp2025037?pageType=en |
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