Electrical Conductivity of Mantle Transition Zone and Water Content Revealed by the Magnetic Data of China Seismo-Electromagnetic Satellite

Abstract

The mantle transition zone (MTZ) plays a key role in the deep global material cycle, while the water content in MTZ is debated from saturated to dry. Since the electrical conductivity is highly sensitive to water, its accurate estimation will greatly help reveal the water content. The high quality and plenty of data are crucial for global-scale conductivity recovery. In this article, we use the magnetic vector data of China seismo-electromagnetic satellite (CSES) to estimate the global mantle electrical structure, accompanying with the Swarm satellite and observatories. In particular, we correct the latitude effect of CSES Level 2 data. The radial conductivity model and uncertainty information of the Earth are obtained by using Bayesian inversion. It is found that large changes in the electrical results of MTZ occur when using the CSES magnetic field data. The conductivity is higher than that inverted from Swarm data, but lower than that from the observatory data. Finally, we, respectively, invert the resistivity structure of the MTZ with two years and nearly nine years of database of CSES, Swarm, and observatories, and analyze the laboratory conductivity model. The results indicate that the water content of the MTZ is less than 0.01 weight%.