Surface Variations in Earth's Time Variable Gravity Field Modelled by the Finite Element Method

In this work, we study the Earth's time variable gravity field, which helps to detect changes that appear in Earth's mass caused by hydrological processes, ice, and ocean dynamics. To compute these changes, we formulate a GRACE-constraint finite element workflow to reconstruct gravity potentials that is implemented in ANSYS software. We examine two different spatial discretizations: a triangular geographic (latitude–longitude) discretization and an icosahedral discretization. For each discretization, we acquire the gravity potential at Earth's surface by imposing Dirichlet and Neumann boundary conditions and verify against an analytical benchmark using error norms, RMSE, and residuals. The obtained results show the importance of discretization choice to maximizing solution accuracy and support finite element modelling as a perspective tool for studying changes in Earth's gravity field.