The Influence of Sea-Level Changes on Geodetic Datums along the East Coast of China

Non-tidal variation on sea level generates immediate changes in gravity field and deformation of the Earth's crust, thus influencing the stability of geodetic datums. To achieve higher accuracy of geodetic datums in coastal and island areas, sea-level changes should be adequately considered when conducting the maintenance of datums. Based on the data of sea-level anomalies from 2014 to 2017 and the theory of load-deformation of elastic spherical earth, this paper demonstrates that impacts of non-tidal ocean load can be quantitatively calculated on geodetic datums along the east coast of China, by using remove-restore technique and combining spherical harmonic analysis of gravity field and Green’s functions to calculate loads. Temporal and spatial analyses on the impacts are conducted with Continuously Operating Reference Stations (CORS) sites along the coast and on the islands. This paper has drawn some conclusions as follows: (1) The impact of non-tidal ocean loads on the east coastal geoid ranges from −4.16 to 4.17 mm, that on ground gravity ranges from −15.44 to 17.02 some conclusions as follows: (1) The impact oranges from −7.55 to 6.69 mm. (2) The impacts are dominated by annual and semi-annual cycles. (3) The impacts appear to be more prominent in coastal areas and on islands than in inland areas.