New insights into Earth’s mantle conductivity and water distribution using the Macau Science Satellite-one data

Water content, whether as free or lattice-bound water, is a crucial factor in determining the Earth’s internal thermal state and plays a key role in volcanic eruptions, melting phenomena, and mantle convection rates. As the electrical conductivity is highly sensitive to water content in the Earth’s interior, it is an important geophysical parameter for understanding the deep Earth water content. Since its launch on May 21, 2023, the MSS-1 satellite has operated for nearly one year, with its magnetometer achieving a precision of less than 0.5 nT after orbital testing and calibration. Orbiting at 450 kilometers with a unique 41-degree inclination, the satellite enables high-density observations across multiple local times, allowing detailed monitoring of low-latitude regions and enhancing data for global conductivity imaging. To better understand the global distribution of water within the Earth’s interior, it is crucial to study internal conductivity structure and water content distribution using data from the MSS-1 satellite. To this aim, we firstly introduce a method for extracting induced magnetic fields related to magnetospheric currents from MSS-1 satellite data. We then develop a trans-dimensional Bayesian approach to derive Earth’s internal conductivity, providing the most probable conductivity structure and an uncertainty analysis. Finally, by integrating the known mineral composition, pressure, and temperature distribution within the mantle, we estimate the water content range in the mantle transition zone, concluding that this region contains the equivalent of up to 3.0 oceans of water, providing compelling evidence that supports the hypothesis of a deep water cycle within the Earth’s interior.