A Model of the Martian Crustal Magnetic Field Using Data from MGS, MAVEN, and Tianwen-1

Mars lacks a global dipole magnetic field but hosts localized magnetic anomalies from magnetized crustal rocks. Accurate descriptions of the crustal magnetic field are crucial for understanding the magnetic environment and geology of Mars. In this study, We construct a Martian crustal magnetic field model using the Equivalent Source Dipole (ESD) approach, integrating data from three missions: Mars Global Surveyor (MGS), Mars Atmosphere and Volatile EvolutioN (MAVEN), and Tianwen-1. To mitigate contamination from solar wind-ionosphere interactions, we use satellite-measured upstream solar wind parameters, including the average values of IMF strength, IMF fluctuation levels, solar wind pressure, and electron density, as indicators of external field interference. The resulting model is then converted to a spherical harmonic (SH) model up to degree 130, achieving a spatial resolution of approximately 165 km at the Martian surface. Compared to previous studies, it exhibits reduced fitting residuals for the horizontal components of MAVEN dataset, confirming the effectiveness of our data selection methodology. Validation with rover measurements reveals that while the model’s predictions are significantly weaker at the InSight landing site, they show better agreement with observations at the Zhurong site than those of previous models. This work could assist in further research on the Martian magnetic environment and its interaction with the solar wind.