| In this paper, the harmonic analysis and application of tides are carried out, based on the measured tidal data of Jigujiao and Lvhuashan stations outside the Yangtze Estuary for many years. The harmonic constants are calculated by the least square method to study the effects of different tidal assemblages and different data lengths on the harmonic analysis results. The depth datum is calculated by standard method and direct prediction method, and the tide level is calculated by the residual water level correction method and the accuracy is verified. The results show that the accuracy of harmonic analysis increases with the increase of tidal number. Comparing with using the observed tide data for many years, the accuracy of harmonic analysis based on annual measured tidal data is generally higher, meanwhile, the accuracy of tidal prediction by using the observed tidal data of adjacent years is relatively high. As for the theoretical minimum tidal surface, the results obtained by the standard method are smaller than those obtained by the direct prediction method. The accuracy of residual water level calculation and verification based on the measured data of Jigujiao and Lvhuashan stations basically meets the practical requirements. |
