Latest Observational Results from the Superconducting Gravimeter at Station Wuhan and Investigation of Ocean Tide Models

Abstract

Using observations of the superconducting gravimeter GWR-C032 at station Wuhan, the tidal gravity parameters reflecting the characteristics of the Earth's interior medium are obtained based on the harmonic analysis after variable preprocessing to the raw data. Meanwhile the gravity loading are calculated using the loading theory and a numerical integral convolution technique based on various global ocean tide models developed by methods of the altimetry technology and finite element with consideration of tidal gauge data as constraints. The loading corrections are carried out for tidal gravity parameters in diurnal and semidiurnal wave bands, respectively in order to investigate the adaptability of global ocean tide models. The numerical results show that the efficiencies of loading correction reach to 91% (O1, NAO99) and 92% (M2, ORI96) for instance. The average efficiencies of the loading corrections obtained with 11 oceanic models for four main constituents (O1, K1, M2 and S2) are 86%, 70%, 73% and 84%, respectively. And the discrepancies between amplitude factors and theoretical values decrease from (2.12%, 1.55%, 1.16% and 0.80%) to (0.31%, 0.39%, 0.34% and 0.08%), respectively. The comparison among various ocean models also shows that the loading correction efficiencies when using NAO99 and ORI96 models are higher than those when using other models. Additionally, other observations obtained with superconducting gravimeters at 7 stations in a network of the Global Geodynamic Project are also adopted to investigate the adaptability of the global ocean models. The results show that there exist obvious local tidal characteristics for different constituents in different ocean models and the earlier constructed SCW80 ocean model can still be used as an important reference in geodesy research.