عنوان مقاله [English]
نویسندگان [English]چکیده [English]
Using tidal potential, the effect of tide on the gravity field, crustal deformation due to tidal force, and gravity variations resulted from the crustal deformation are presented. Tidal potential is divided into constant and periodic (diurnal and semi-diurnal) constituents, and for each constituents crustal displacements in radial, South-North, and East-West directions are computed. The aforementioned computations, which algorithmically can be summarized as follows, are implemented in a software with the capability of computing the tidal potential and the resulting crustal deformation at any time and location: (i) Using right ascension coordinates (?, ?) of the Moon and Sun, and time, zenith angle of the celestial bodies is computed as a function of time and location on the surface of the Earth. (ii) Constant and periodic constituents of the tidal potential are computed for the given points on Earth surface at the given times. (iii) Crustal displacements caused by the tidal force in the radial, South-North, and East-West directions are computed. (iv) The computed tidal potential constituents and the related tidal displacements are presented in both graphical and tabular formats. As the case study, using the aforementioned software, tidal potential and tidal deformation of the crust at geographical region of Iran is computed. Among the practical applications of this study and the developed software followings are outstanding: (i) Removal of the crustal deformation due to tide from the Global Navigation Satellite System (GNSS) observations. (ii) Removal of direct tidal effect from gravity observations. (iii) Removal of the indirect tidal gravity effect due to crustal deformation from the gravity observations. (iv) Removal of the direct tidal effect from the geoid. (v) Removal of indirect effect due to crustal deformation from the geoid. (vi) Removal of the tidal effects from the height systems.