There are two main approaches in modeling the lithospheric magnetic field, the comprehensive and the sequential one. The comprehensive aims at modeling the magnetic field of multiple sources simultaneously. The sequential one removes all known non-lithospheric field sources and uses the residuals to model the lithospheric magnetic field. Lithospheric field models can be either global or regional. I have worked with the Revised Spherical Cap Harmonic Analysis (R-SCHA), which allows us to model simultaneously data obtained at different altitudes, i.e., data obtained by satellites, airplanes, ships and magnetic observatories. I used this technique to produce a high spatial resolution model of the lithospheric magnetic field over Southern Africa: A high-resolution lithospheric magnetic field model over southern Africa based on a joint inversion of CHAMP, Swarm, WDMAM,and ground magnetic field data, Vervelidou et al., 2018, Solid Earth, 9, pp. 897–910, doi: 10.5194/se-9-897-2018.
Lithospheric field models are useful because they allow us to infer information about Earth’s lithosphere, and specifically Earth’s crust where most of the lithospheric magnetic sources reside (that is why the lithospheric magnetic field is commonly termed the crustal magnetic field). I have used spectral analyses to infer the thickness and the magnetization of the crustal sources. As a first step, together with my Phd advisor, we proposed a statistical expression for the Earth’s lithospheric magnetic field power spectrum, which provides a very good fit to available lithospheric field models: A statistical spatial power spectrum of the Earth’s lithospheric magnetic field, Thébault&Vervelidou, 2015, Geophysical Journal International, 201(2), pp. 605-620, doi:10.1093/gji/ggu463. We also proposed a regional magnetic field power spectrum, the R-SCHA power spectrum. By combining the data-based R-SCHA power spectrum with the statistical power spectrum, one can infer the men thickness and magnetization of the crustal magnetic field sources: Global maps of the magnetic thickness and magnetization of the Earth’s lithosphere, Vervelidou&Thébault, 2015, Earth Planets and Space, 67, doi:10.1186/s40623-015-0329-5.
