Detecting the signal cycle of the deep Earth’s dynamic processes based on GRACE satellite and CHAOS-7 model data

This study is led by Dr. ZhengTao Wang (School of Geodesy and Geomatics, Wuhan University) and was funded by the National Natural Science Foundation of China (Grant Nos. 42274003, 41974007, and 41774019).

Variations in Earth’s gravity field over annual to decadal timescales are generally attributed to changes in land water storage and ocean mass. However, seasonal observations reveal notable discrepancies that cannot be fully explained by surface processes alone. While part of the observed gravity signal originates from mass redistribution at Earth’s surface, growing evidence suggests that flows within Earth’s liquid core may also contribute to gravity variations on interannual to decadal timescales. These findings indicate that some previously unexplained gravity signals may be linked to dynamic processes occurring deep within Earth’s interior.

Comparative analyses of gravity and magnetic field data reveal shared modes of variability, suggesting a close connection between the two systems. Using GRACE observations, we detect pronounced gravity field variations with periods ranging from approximately 4.6 to 8.6 years, which show a strong association with the core magnetic field. In addition, periodic signals with substantial power at interannual to decadal time scales are identified in the first six components of the CHAOS-7 radial secular acceleration. These findings are consistent with earlier observations and reinforce growing evidence of dynamic interactions between Earth’s deep interior and its global geophysical fields.

Previous studies suggest that processes occurring in Earth’s core may account for a measurable portion of observed gravity field variations—potentially up to 10%—raising the possibility that core mass transfer could be detected through geodetic observations in the future. The correlations identified between gravity and magnetic fields in this study point to a dynamic connection between deep Earth processes and global gravity variations. Achieving a clear detection, however, depends on accurately accounting for and removing the dominant contributions from surface processes. While this study incorporates a wide range of adequate models to mitigate surface signals, uncertainties in these models remain a key challenge. Future work will focus on improving the representation and removal of surface process effects to further isolate the signature of core dynamics.

Identifying clear signatures of Earth’s core processes in gravity and other geodetic observations is crucial for advancing research on core dynamics. In this context, our analysis of the correlations between the gravity field and the magnetic field offers a new perspective and lays important groundwork for future investigations into deep Earth mass variations. By further exploring how core dynamic processes drive global mass redistribution and surface deformation, this line of research will contribute to a more comprehensive understanding of Earth’s large-scale mass dynamics.

See the article:

Detecting the signal cycle of the deep Earth’s dynamic processes based on GRACE satellite and CHAOS-7 model data

http://doi.org/10.26464/epp2026016