Abstract:To verify the feasibility of using portable relative gravimeters for short-term gravity tidal observations to improve the ocean tidal model, we conduct a same-site comparison at the Xiamen seismic station. Using the stational ocean tidal model corrected from FES2004 with long term gPhone data as the reference, we separate the static observation residual sequences of gPhone, CG-5 and CG-6 gravimeters. The spectrums show that the noise level(non-linear drift) of CG-5 and CG-6 at 1 CPD(circle per day) and 2 CPD are slightly higher than that of the gPhone. This indicates that the impact on the semi-diurnal and full-diurnal tides analysis is small, and the observation accuracy can meet the needs of short-time tide model correction. We built the stational tide model at Pingtan island, which is corrected from FES2014 with the data recorded by a CG-5 gravimeter. The gravity tidal load during the absolute gravity observation period 35 d ago is remeasured. In contrast with the FES2014 model, the standard deviation of group mean residual after ocean tidal correction with our stational model is reduced from 2.7 μGal to 1.8 μGal. The feasibility of CG portable relative gravimeter for tidal load observation is verified.