GRACE Follow-on in Gradiometry Mode: New Insights and Opportunities for Geosciences

We exploit the applicability of GRACE 'Gradiometer Mode' (GRACE-GM) in various subdisciplines of geosciences. Firstly, we derive gravitational gradients induced by geophysical active regions through GRACE-GM. The full GRACE-GM gravitational gradient tensor demonstrates very similar behavior to GOCE-based gradiometer measurements. Coherence analysis between GRACE-GM and GOCE gradiometer estimates demonstrated a nearly 80% correlation between the two missions. The contribution of GRACE-GM in ionospheric studies is also investigated, and phenomena highly correlated with the Earth's magnetic field are evident in GRACE-GM estimates. In particular, North and South Pole magnetic fluctuations, the Earth's magnetic field inclination and the Birkeland currents are evident in GRACE-GM estimates. GRACE-GM opens new opportunities for in-depth study of the Earth as a system, where gravitational gradient measurements can be proven an invaluable tool for better understanding and monitoring of the upper ionosphere layers. We argue that future enhancements of the proposed method, such as higher frequency accelerations (i.e., 10Hz), will expand and enhance the GRACE follow-on objectives that will lead to significant new insights, discoveries and applications in the Earth system and geosciences.