Retrieving complete spherical Bouguer and isostatic gravity anomalies using global gravity forward models

SUMMARY The estimation of topographic gravity field models has attracted significant interest in recent years due to its growing relevance in Earth sciences. In this study, we present a robust methodology for the computation and comprehensive validation of global, complete spherical Bouguer and isostatic gravity anomalies that are essential for accurately interpreting subsurface mass distributions therefore geological structures. We synthesize these crucial gravitational functionals by leveraging spherical harmonic coefficients from high-resolution global gravity field models and various topographic/topographic–isostatic gravity field models. Our findings underscore the critical role of comprehensive terrain corrections in deriving physically meaningful, complete Bouguer gravity fields. The calculated global anomalies demonstrate strong coherence with established benchmark data sets, such as the World Gravity Map 2012. Residual differences are primarily attributed to variations in input Digital Terrain Models. Comparisons with regional Bouguer data sets reveal systematic biases that are largely explained by differing terrain correction methodologies. After removing this effect, there is a high level of consistency between the calculated global and published regional data sets, highlighting the utility of our global solutions, particularly in regions with sparse terrestrial data. Furthermore, the globally computed isostatic gravity anomalies exhibit significant agreement with both external global and diverse regional data sets, notably without the large systematic biases observed in Bouguer comparisons. This agreement reflects the effectiveness of the combined topographic and isostatic corrections in capturing Earth’s mass balance. This research provides valuable tools for new studies in the geoscience community by offering globally consistent and complete Bouguer and isostatic gravity field anomalies that have been rigorously validated for the ICGEM service.