Ocean Tidal Loading Correction to Tilt Observations at Sheshan Station

With the latest ocean tide model of TPXO6 and China regional tidal data,the tilt tidal loading are calculated based on Farrell's load theory.Simultaneously,the tilt tidal parameters are obtained by processing the tilt observations at Sheshan station using BAYTAP-G software for harmonic analysis.After that,the loading correction is carried out.The numerical results show,after correction,that tilt tidal parameters of EW component are closer to the theoretical ones while the values of NS component for semidiurnal tides are still apart from the theoretical ones.This means that the EW component of tilt is mainly influenced by ocean tide,which is more than 60%,even reaches to 96% for O_1.And the NS component of tilt is more influenced by the non-tidal effects than EW component.For example,for N_2 constituent,the non-tidal effects are up to 70%.However the inaccuracy of the ocean tide model in local area may contribute more to the high percentage.