Influence of ocean tidal loading on continuous gravity observations in eastern China

Global and regional ocean tidal models were used to analyze the gravity effects of ocean tidal loading on continuous gravity observations in eastern China. The accuracies of tidal loading gravity correction results for 21 gPhone and superconducting gravity stations were evaluated. The global ocean tidal model was most effective for gravity correction at inland stations (up to 90%), but less effective at coastal stations (only 60%). Taking into account regional ocean tidal models, the effectiveness of tidal loading correction increased to 80%, and the root sum square of the residual gravity series was 0.7450 ~ 0.9733\({\times 10}^{-8}\text{m}{\text{s}}^{-2}\). The best tidal loading gravity correction was obtained by combing the global FES2004 model and regional OSU.chinasea.2010 model (root sum square of 0.7450\({\times 10}^{-8}\text{m}{\text{s}}^{-2}\)). Using this combination, the tidal loading gravity amplitude in the China Sea and adjacent areas was calculated; tidal loading gravity was. Very low gravity effects were obtained inland and for island interiors; however, tide loading gravity was relatively larger along the coast, especially the southeast coast and Bohai Bay. Moreover, the amplitude changed drastically possibly owing to offshore topography. Our results provide a reference for selecting ocean tidal models for high-precision analysis of continuous gravity observations in China.