Precise tidal gravity recorded with superconducting gravimeters at stations Wuhan (China) and Kyoto (Japan)

Three long series of tidal gravity observations, totalizing approximately 2 4 years and recorded with three superconducting gravimeters, T004, T008, an d T009, at stations Wuhan (China) and Kyoto (Japan), are studied. The tidal amplitude factors and phase differences are determined precisely using Ete rna and Nsv techniques. The precision of the main tidal amplitudes is at th e same level of 0.01 mu Gal. The atmospheric gravity signals are corrected using the coefficients determined with a regression method between tidal gr avity residual and station air pressure. The oceanic gravity signals are mo deled based on five global oceanic models. It is found that the oceanic mod els developed by the analysis of measurements from Topex/Poseidon altimeter s have the best fit to the superconducting gravimeter measurements, since t he observed residuals and the discrepancies between the amplitude factors a nd the theoretical tidal models are reduced more significantly. The long-pe riod gravity variations are dominated by the non-linear drift phenomena of the instruments, and the short-term variations in gravity are due to the ba ckground noise at the stations.