A 100-degree lithospheric magnetic field model constructed using MSS-1, Swarm-A, and CHAMP satellite data

By combining data from the Challenging Minisatellite Payload (CHAMP), Swarm-A, and newest Macau Science Satellite-1 (MSS-1) missions, we constructed a lithospheric magnetic field model up to spherical harmonic degree N = 100. To isolate the lithospheric magnetic field signals, we utilized the latest CHAOS-8 (CHAMP, Ørsted, and SAC-C 8) model and MGFM (Multisource Geomagnetic Field Model) to remove nonlithospheric sources, including the core field, magnetospheric field, ocean tidal field, and ocean circulation field. Subsequently, orbit-by-orbit processing was applied to both scalar and vector data, such as spherical harmonic high-pass filtering, singular spectrum analysis, and line leveling, to suppress noise and residual signals along the satellite tracks. With an orbital inclination of only 41°, MSS-1 effectively captures fine-scale lithospheric magnetic field signals in mid- to low-latitude regions. Its data exhibit a root mean square error of only 0.77 nT relative to the final model, confirming the high quality and utility of lithospheric field modeling. The resulting model exhibits excellent consistency with the MF7 (Magnetic Field Model 7), maintaining a high correlation up to N = 90 and still exceeding 0.65 at N = 100. These results demonstrate the reliability and value of MSS-1 data in global lithospheric magnetic field modeling.