Space gravity measurements have been mainly used to study temporal mass variations at the Earth’s surface and within the mantle. Nevertheless, recent studies indicate that mass variations due to the Earth’s core might be observable in the variations of the gravity field as measured by GRACE and GRACE-FO satellites. Moreover, a possible correlation between the variable gravity and magnetic fields has been pointed out at decadal time scales. To access these gravity variations, other known surficial effects must be corrected such as hydrological, oceanic or atmospheric loadings. However, these corrections also add errors to the final product.

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 low degree spherical harmonic coefficients, saying up to degree and order 8. We compare the corrections of several glacial isostatic adjustment, hydrological, oceanic and atmospheric loading models for these larges scales. These comparisons provide us with an estimate of the uncertainty associated with each correction.

With the benefit of nearly two decades of space gravity data, we finally create a time-variable gravity field product, which considered the multiple corrections indicated above. This offers the possibility to revisit the correlation analyses between the gravity and magnetic fields.