Study On Numerical Analysis Expansion Of Tide-generating Potential By Computer

The tide-generating potential is a scalar expression of the tide-generating force,which reflects the cyclic role of tide-generating force on the earth. In high-precisiongeodetic surveying, the tide-generating force is one of few mechanical turbulencefactors, which can be computed accurately and excluded. So the harmonic expansionof tide-generating potential is of great significance in dynamical geodesy, andtide-generating potential expansion is the basic theory of earth tide and the workfoundation of tide observation analysis.At present, there are two major expansion methods of tide-generating potential:frequency spectrum analysis method and analytical method. The results show that theaccuracy of the former has large uncertainty, and this accuracy is related to that ofsome theoretical values (astronomical constants and ephemeris etc.) and depends onthe separation method of tidal waves. The accuracy of the later is certain, related onlyto the theoretical values. In this thesis, analytical method was employed to implementtide-generating potential expansion, with an eye single to the principle andimplementation steps of the Doodson and surface spherical harmonics expansions.After that, data structure was built rationally with easy expression, according tofeatures of tide-generating potential data, and numerical-analysis expansion integratedsoftware of tide-generating potential was provided with user interface on C#andrealizing program on MATLAB, and the Doodson and surface spherical harmonicsexpansions were carried out through this software using numerical operation bycomputer, with the expansion efficiency of numerical operation was far above that oftraditional symbolic operation. In the process of expansions, the ELP2000-85Moonephemeris and the Newcomb Sun ephemeris were adopted. At last, the YZD11andYZS11tidal potential catalogues with the same level as that (0.05nm/s2) of the X189catalogue were obtained, in which amplitudes less than10-8were given up, and thenumber of expansion terms was10430and8411respectively. This thesis verified thefeasibility of analytic expansion of tide-generating potential using numerical operationby computer, and realized the surface spherical harmonics expansion for the first time.Further, according to the normalized definitions for different expansions of tide-generating potential, this thesis figured out conversion coefficients between theDoodson, surface spherical harmonics and HW expansions, realizing conversions todifferent tidal potential catalogues.