Weijia Kuang Space Geodesy Branch, Code 926, NASA Goddard Space Flight Center Understanding dynamical processes in the Earth's outer core via surface geomagnetic and gravity observation Wednesday 17th August, 14:05-14:55pm, Carslaw Building Room 373. The Earth’s fluid outer core is in convection through its history, on time scales ranging from several years to perhaps geological time scales. Manifestation of the dynamical processes includes observed surface geomagnetic and paleomagnetic properties. However it also includes gravity changes on similar time scales that may be also observable at the Earth’s surface. We study the latter phenomena, aiming at obtaining insights on core dynamics through surface gravity observations, in particular, searching for spatial-temporal patterns in gravity field that are similar to those of geomagnetic field. Associated with the core convection are density anomalies in the bulk of the fluid core, and the non-hydrostatic pressure. Both contribute to gravity variation in the following forms: mass-redistribution in the core due to fluid flow, and the internal pressure loading on the core-mantle boundary (CMB). In the past, effects on time-variable gravity from the two processes have only been partially and separately examined. In our study here, we investigate both processes through the MoSST core dynamics model, and the PREM model for the mantle that are used to obtain the relevant Love numbers. Our numerical results show that the mass redistribution in the core produces the largest gravity anomaly. However, the mantle deformation in response to this anomaly offsets the gravity variation. Consequently, the gravity variation due to pressure loading on the CMB is therefore significant, which is “in-phase” with that due to the core mass-redistribution. Therefore the net gravity variation is larger than the estimations of the individual effects and, in particular, its spatial-temporal variation is similar to that of the core flow. Our results suggest that long-term, global gravity measurements could provide a non-magnetic probe to dynamical processes in the Earth’s fluid core.