The GRACE and GRACE Follow-On (GRACE-FO) missions have been providing monthly time-variable gravity field estimates since 2002 with a one-year gap between 2017 and 2018. The Level 2 data products are available through several processing centers with independent computation strategies. As part of the GRACE/GRACE-FO Science Data System (SDS), the Center of Space Research (CSR), the German Research Centre for Geosciences (GFZ) and the Jet Propulsion Laboratory (JPL) process gravity data with RL06 standards. The French Space Agency (CNES) and the Graz University of Technology deliver GRACE gravity fields models respectively named CNES/GRGS RL05 and ITSG-GRACE2018. The International Combination Service for Time-variable Gravity Field (COST-G) makes available a product resulting of the combination of different processing centers including among others the previously mentioned products. In addition to GRACE data, the European Space Agency (ESA) has been delivering Level 2 data products from the Swarm mission since 2013. Swarm data provides information for the gap-fill between the GRACE and GRACE-FO missions. With appropriate corrections, these datasets are valuable inputs to investigate the deep Earth’s interior. We put the focus on the core-mantle boundary (CMB) processes and core dynamics that would induce gravity field perturbations at the Earth’s surface.

Earth’s core dynamical processes inferred from geomagnetic field measurements are characterized by large-scale patterns. Studying them via gravity field observations involves the use of spherical harmonic coefficients up to degree and order 8. Particular attention needs to be dedicated to Stokes coefficients that are affected by problematic reconstruction effects such as C_2,0 or C_3,0. The comparison of time-series from various processing centers with Satellite-Laser Ranging (SLR) gravity products and hydrological loading models provides information on the consistency between different solutions and the accuracy of space gravity-field measurements. The corrections of hydrological and glacial isostatic adjustment (GIA) effects are an additional source of error in the determination of the gravity field. For example, the current uncertainty of the GIA model over North America might lead to an error of some 10% for specific Stokes coefficients. Mismodelling in the seasonal loading could also affect the retrieved Stokes coefficients.

Here, we discuss the differences between the gravity field solutions in terms of accuracy of the observed gravity field variation and finally the ability to detect core signals.