A general spatial interpolation method for tidal properties has been developed by solving a partial differential equation with a combination of different orders of harmonic operators using a mixed finite element metho...A general spatial interpolation method for tidal properties has been developed by solving a partial differential equation with a combination of different orders of harmonic operators using a mixed finite element method. Numerically, the equation is solved implicitly without iteration on an unstructured triangular mesh grid. The paper demonstrates the performance of the method for tidal property fields with different characteristics, boundary complexity, number of input data points, and data point distribution. The method has been successfully applied under several different tidal environments, including an idealized distribution in a square basin, coamplitude and cophase lines in the Taylor semi-infiite rotating channel, and tide coamplitude and cophase lines in the Bohai Sea and Chesapeake Bay. Compared to Laplace’s equation that NOAA/NOS currently uses for interpolation in hydrographic and oceanographic applications, the multiple-order harmonic equation method eliminates the problem of singularities at data points, and produces interpolation results with better accuracy and precision.展开更多
The synthetic tidal parameters with high spatial resolution for gravity over China and its neighbor area are constructed with Earth＇s tidal model and ocean tide loading calculated using TPXO7 global ocean tide model ...The synthetic tidal parameters with high spatial resolution for gravity over China and its neighbor area are constructed with Earth＇s tidal model and ocean tide loading calculated using TPXO7 global ocean tide model as well as tidal data over China seas. The comparison between synthetic parameters and ones observed by spring gravimeters at some seismic network stations and Hong Kong station and one observed by super-conducting gravimeter at Wuhan station shows that the average differences in amplitude factors and phases are smaller than 0.005 and 0.5° respectively; and that the discrepancies between observational and synthetic parameters are dependent on gravimetric technique in that the synthetic parameters are in well agreement with the superconducting gravimetric observations. This also indicates that the synthetic result is a good estimation for tidal gravity, and the numerical results in the present paper not only can provide ground and space gravimetry such as absolute gravimetry with correction model of tidal gravity, but also provide effective tidal parameters over areas where no observation is carried out.展开更多
19-year tidal data of the 3 stations, Huludao, Qinhuangdao and Kanmen, have totally been analysed, and the amplitudes and phases of 472 tidal constituents have been calculated with a resolution of Δ≥ 0.002 2 /h. Bas...19-year tidal data of the 3 stations, Huludao, Qinhuangdao and Kanmen, have totally been analysed, and the amplitudes and phases of 472 tidal constituents have been calculated with a resolution of Δ≥ 0.002 2 /h. Based on the draconitic tide, the anomalistic tide and pole tide obtained, the ultra-long-period variations of the mean sea level have been predicted. The annual tidal analysis of 19-year data at the above-mentioned stations and at Tanggu, Longkou has been carried out. The stability of the annual tidal analysis has been investigated with regard to the astronomical factors, the nonlinear effects and the variations of sea-bottom topography.展开更多
文摘A general spatial interpolation method for tidal properties has been developed by solving a partial differential equation with a combination of different orders of harmonic operators using a mixed finite element method. Numerically, the equation is solved implicitly without iteration on an unstructured triangular mesh grid. The paper demonstrates the performance of the method for tidal property fields with different characteristics, boundary complexity, number of input data points, and data point distribution. The method has been successfully applied under several different tidal environments, including an idealized distribution in a square basin, coamplitude and cophase lines in the Taylor semi-infiite rotating channel, and tide coamplitude and cophase lines in the Bohai Sea and Chesapeake Bay. Compared to Laplace’s equation that NOAA/NOS currently uses for interpolation in hydrographic and oceanographic applications, the multiple-order harmonic equation method eliminates the problem of singularities at data points, and produces interpolation results with better accuracy and precision.
基金The Knowledge Innovation Program of the Chinese Academy of Sciences (KZCX2-YW-133)National Nature Science Foundation of China (40730316, 40574034).
文摘The synthetic tidal parameters with high spatial resolution for gravity over China and its neighbor area are constructed with Earth＇s tidal model and ocean tide loading calculated using TPXO7 global ocean tide model as well as tidal data over China seas. The comparison between synthetic parameters and ones observed by spring gravimeters at some seismic network stations and Hong Kong station and one observed by super-conducting gravimeter at Wuhan station shows that the average differences in amplitude factors and phases are smaller than 0.005 and 0.5° respectively; and that the discrepancies between observational and synthetic parameters are dependent on gravimetric technique in that the synthetic parameters are in well agreement with the superconducting gravimetric observations. This also indicates that the synthetic result is a good estimation for tidal gravity, and the numerical results in the present paper not only can provide ground and space gravimetry such as absolute gravimetry with correction model of tidal gravity, but also provide effective tidal parameters over areas where no observation is carried out.
文摘19-year tidal data of the 3 stations, Huludao, Qinhuangdao and Kanmen, have totally been analysed, and the amplitudes and phases of 472 tidal constituents have been calculated with a resolution of Δ≥ 0.002 2 /h. Based on the draconitic tide, the anomalistic tide and pole tide obtained, the ultra-long-period variations of the mean sea level have been predicted. The annual tidal analysis of 19-year data at the above-mentioned stations and at Tanggu, Longkou has been carried out. The stability of the annual tidal analysis has been investigated with regard to the astronomical factors, the nonlinear effects and the variations of sea-bottom topography.
