The rotation of the Earth and the related length of the day (LOD) are predominantly affected by tidal dissipation through the Moon and the growth of the Earth’s core. Due to the increased concentration of mass around...The rotation of the Earth and the related length of the day (LOD) are predominantly affected by tidal dissipation through the Moon and the growth of the Earth’s core. Due to the increased concentration of mass around the rotation axis of the spinning Earth during the growth of the core the rotation should have been accelerated. Controversially the tidal dissipation by the Moon, which is mainly dependent on the availability of open shallow seas and the kind of Moon escape from a nearby position, acts towards a deceleration of the rotating Earth. Measurements of LOD for Phanerozoic and Precambrian times open ways to solve questions concerning the geodynamical history of the Earth. These measurements encompass investigations of growth patterns in fossils and depositional patterns in sediments (Cyclostratigraphy, Tidalites, Stromatolites, Rhythmites). These patterns contain information on the LOD and on the changing distance between Earth and Moon and can be used as well for a discussion about the growth of the Earth’s core. By updating an older paper with its simple approach as well as incorporating newly published results provided by the geoscientific community, a moderate to fast growth of the core in a hot early Earth will be favored controversially to the assumption of a delayed development of the core in an originally cold Earth. Core development with acceleration of Earth’s rotation and the contemporaneous slowing down due to tidal dissipation during the filling of the ocean may significantly interrelate.展开更多
The adaptability of recent ocean tidal models and Earth tidal models is investigated comprehensively by means of 22 high precision tidal gravity observation series at 20 stations of the Global Geodynamics Project. Car...The adaptability of recent ocean tidal models and Earth tidal models is investigated comprehensively by means of 22 high precision tidal gravity observation series at 20 stations of the Global Geodynamics Project. Careful preprocessing of the original observations was carried out using international standard algorithms and the tidal gravity parameters were computed. The gravity load vectors of 8 main constituents are obtained based on loading computation theory and various global ocean models. The loading corrections of 14 secondary constituents are obtained based on a two-dimensional interpolation technique. Considering different characteristics of the wave amplitude, a method of “non-identical weighted mean” is developed for computing the av-eraged observed residual and remaining residual vectors at each station. The efficiency of the loading correction and the discrepancy between corrected amplitude factors and theoretical ones are analyzed. Meanwhile the calibration problem of the instruments is also discussed. After loading correction, the averaged tidal gravity parameters for all stations are obtained. The results show that the discrepancies between the global mean amplitude factors and theoretical values are less than 0.3%, the largest calibration error of the instruments is less than 0.5%. On the other hand, there are indications that the slight phase advance of K1 with respect to O1 in Mathews’ theory could be verified by ground based tidal gravity observations.展开更多
Based on the 28 series of the high precision and high minute sampling tidal gravity observations at 20 stations in Global Geodynamics Project (GGP) network, the resonant parameters of the Earth's nearly diurnal fr...Based on the 28 series of the high precision and high minute sampling tidal gravity observations at 20 stations in Global Geodynamics Project (GGP) network, the resonant parameters of the Earth's nearly diurnal free wobble (including the eigenperiods, resonant strengths and quality factots) are precisely determined. The discrepancy of the eigenperiod between observed and theoretical values is studied, the important conclusion that the real dynamic ellipticity of the liquid core is about 5% larger than the one under the static equilibrium assumption is approved by using our gravity technique. The experimental Earth's tidal gravity models with considering the nearly diurnal free wobble of the Earth's liquid core are constructed in this study. The numerical results show that the difference among three experimental models is less than 0.1%, and the largest discrepancy compared to those widely used nowdays given by Dehant (1999) and Mathews (2001) is only about 0.4%. It can provide with the most recent real experimental tidal gravity models for the global study of the Earth's tides, geodesy and space techniques and so on.展开更多
Frequencies of frequency standards are shifted by the local static gravity red shifts and also modulated by the tidal relativistic red shifts. We compute the tidal relativistic red shifts using a time-domain method an...Frequencies of frequency standards are shifted by the local static gravity red shifts and also modulated by the tidal relativistic red shifts. We compute the tidal relativistic red shifts using a time-domain method and present the numerical results for the National Institute of Metrology （NIM） in Beijing, Laboratoire National de Metrologie et Essais-Systeme de References Temps-Espaee （LNE-SYRTE） in Paris and Physikalisch-Teehnische Bundesanstalt （PTB） in Braunschweig. The differences of the tidal relativistic red shift approach as large as 1.1 × 10^-16 when frequency standards at NIM are compared with those at SYRTE and PTB. Moreover, the tidal relativistic red shifts of frequency standards in space stations are also computed.展开更多
Earthquake prediction is considered impossible for there is no scientific way to find the date and time, the location, and the magnitude of an earthquake. A new idea is introduced in this paper—earth rotation harmoni...Earthquake prediction is considered impossible for there is no scientific way to find the date and time, the location, and the magnitude of an earthquake. A new idea is introduced in this paper—earth rotation harmonics triggered natural volcano and earthquake. With earth rotation harmonics response model for a location, it could be possible to calculate the earthquake date and time, and the magnitude. Properties of earth rotation harmonics triggered earthquake are discussed and verified with earthquake data from USGS website. Also, both earth tide and ocean tide effects on earthquake are discussed and verified with earthquake data—tides did not trigger the natural earthquake, they only affect the earthquake activities and time.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
The global oceanic/atmospheric tides exert decelerating/accelerating secular torques on the Earth rotation. We developed new formulations to accurately calculate amounts of two kinds of secular tidal torques. After Me...The global oceanic/atmospheric tides exert decelerating/accelerating secular torques on the Earth rotation. We developed new formulations to accurately calculate amounts of two kinds of secular tidal torques. After Melchior, we found that an additional factor 1+k-l = 1.216, which has been formerly neglected, must be multiplied unto the tidal torque integral. By using our refined formulations and the recent oceanic/atmospheric global tide models, we found that:(i) semidiurnal oceanic lunar/solar tides exert decelerating torques of about-4.462 × 10^(16)/-0.676 × 10^(16) Nm respectively and(ii) atmospheric S_2 tide exerts accelerating torque of 1.55 × 10^(15) Nm. Former estimates of the atmospheric S_2 tidal torque were twice as large as our estimate due to improper consideration of loading effect. We took the load Love number for atmospheric loading effect from Guo et al.(2004). For atmospheric loading of spherical harmonic degree two, the value of k′=-0.6031 is different from that for ocean loading as k′ =-0.3052,while the latter is currently used for both cases-ocean/atmospheric loading-without distinction. We discuss(i) the amount of solid Earth tidal dissipation(which has been left most uncertain) and(ii) secular changes of the dynamical state of the Earth-Moon-Sun system. Our estimate of the solid Earth tidal torque is-4.94×10^(15) Nm.展开更多
文摘The rotation of the Earth and the related length of the day (LOD) are predominantly affected by tidal dissipation through the Moon and the growth of the Earth’s core. Due to the increased concentration of mass around the rotation axis of the spinning Earth during the growth of the core the rotation should have been accelerated. Controversially the tidal dissipation by the Moon, which is mainly dependent on the availability of open shallow seas and the kind of Moon escape from a nearby position, acts towards a deceleration of the rotating Earth. Measurements of LOD for Phanerozoic and Precambrian times open ways to solve questions concerning the geodynamical history of the Earth. These measurements encompass investigations of growth patterns in fossils and depositional patterns in sediments (Cyclostratigraphy, Tidalites, Stromatolites, Rhythmites). These patterns contain information on the LOD and on the changing distance between Earth and Moon and can be used as well for a discussion about the growth of the Earth’s core. By updating an older paper with its simple approach as well as incorporating newly published results provided by the geoscientific community, a moderate to fast growth of the core in a hot early Earth will be favored controversially to the assumption of a delayed development of the core in an originally cold Earth. Core development with acceleration of Earth’s rotation and the contemporaneous slowing down due to tidal dissipation during the filling of the ocean may significantly interrelate.
基金supported jointly by the Knowledge Innovation Project(Grant No.KZCX3-SW-131)the Hundred Talents Program,the Chinese Academy of Sciences,the National Natural Science Foundation of China(Grant No.40374029)the Key International Scientific Cooperation Project via the Ministry of Sciences and Technology of China(Grant No.2002CB713904).
文摘The adaptability of recent ocean tidal models and Earth tidal models is investigated comprehensively by means of 22 high precision tidal gravity observation series at 20 stations of the Global Geodynamics Project. Careful preprocessing of the original observations was carried out using international standard algorithms and the tidal gravity parameters were computed. The gravity load vectors of 8 main constituents are obtained based on loading computation theory and various global ocean models. The loading corrections of 14 secondary constituents are obtained based on a two-dimensional interpolation technique. Considering different characteristics of the wave amplitude, a method of “non-identical weighted mean” is developed for computing the av-eraged observed residual and remaining residual vectors at each station. The efficiency of the loading correction and the discrepancy between corrected amplitude factors and theoretical ones are analyzed. Meanwhile the calibration problem of the instruments is also discussed. After loading correction, the averaged tidal gravity parameters for all stations are obtained. The results show that the discrepancies between the global mean amplitude factors and theoretical values are less than 0.3%, the largest calibration error of the instruments is less than 0.5%. On the other hand, there are indications that the slight phase advance of K1 with respect to O1 in Mathews’ theory could be verified by ground based tidal gravity observations.
基金supported jointly by the National Outstanding Youth Science Foundation of China (Grant No.49925411)the Knowledge Innovation Project of the Chinese Academy of Sciences(Grant No.KZCX3-CW-131)the National Natural Science Foundation of China(Grant No.40174022).
文摘Based on the 28 series of the high precision and high minute sampling tidal gravity observations at 20 stations in Global Geodynamics Project (GGP) network, the resonant parameters of the Earth's nearly diurnal free wobble (including the eigenperiods, resonant strengths and quality factots) are precisely determined. The discrepancy of the eigenperiod between observed and theoretical values is studied, the important conclusion that the real dynamic ellipticity of the liquid core is about 5% larger than the one under the static equilibrium assumption is approved by using our gravity technique. The experimental Earth's tidal gravity models with considering the nearly diurnal free wobble of the Earth's liquid core are constructed in this study. The numerical results show that the difference among three experimental models is less than 0.1%, and the largest discrepancy compared to those widely used nowdays given by Dehant (1999) and Mathews (2001) is only about 0.4%. It can provide with the most recent real experimental tidal gravity models for the global study of the Earth's tides, geodesy and space techniques and so on.
基金Supported by the National Key R&D Program of China under Grant No 2016YFF0200200
文摘Frequencies of frequency standards are shifted by the local static gravity red shifts and also modulated by the tidal relativistic red shifts. We compute the tidal relativistic red shifts using a time-domain method and present the numerical results for the National Institute of Metrology （NIM） in Beijing, Laboratoire National de Metrologie et Essais-Systeme de References Temps-Espaee （LNE-SYRTE） in Paris and Physikalisch-Teehnische Bundesanstalt （PTB） in Braunschweig. The differences of the tidal relativistic red shift approach as large as 1.1 × 10^-16 when frequency standards at NIM are compared with those at SYRTE and PTB. Moreover, the tidal relativistic red shifts of frequency standards in space stations are also computed.
文摘Earthquake prediction is considered impossible for there is no scientific way to find the date and time, the location, and the magnitude of an earthquake. A new idea is introduced in this paper—earth rotation harmonics triggered natural volcano and earthquake. With earth rotation harmonics response model for a location, it could be possible to calculate the earthquake date and time, and the magnitude. Properties of earth rotation harmonics triggered earthquake are discussed and verified with earthquake data from USGS website. Also, both earth tide and ocean tide effects on earthquake are discussed and verified with earthquake data—tides did not trigger the natural earthquake, they only affect the earthquake activities and time.
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.
基金supported by the Space Geodesy Technology Development Program of Korea Astronomy and Space Science Institutesupported by the NSFC(grant Nos.41631072,41721003,41574007 and 41429401)the Discipline Innovative Engineering Plan of Modern Geodesy and Geodynamics(grant No.B17033)
文摘The global oceanic/atmospheric tides exert decelerating/accelerating secular torques on the Earth rotation. We developed new formulations to accurately calculate amounts of two kinds of secular tidal torques. After Melchior, we found that an additional factor 1+k-l = 1.216, which has been formerly neglected, must be multiplied unto the tidal torque integral. By using our refined formulations and the recent oceanic/atmospheric global tide models, we found that:(i) semidiurnal oceanic lunar/solar tides exert decelerating torques of about-4.462 × 10^(16)/-0.676 × 10^(16) Nm respectively and(ii) atmospheric S_2 tide exerts accelerating torque of 1.55 × 10^(15) Nm. Former estimates of the atmospheric S_2 tidal torque were twice as large as our estimate due to improper consideration of loading effect. We took the load Love number for atmospheric loading effect from Guo et al.(2004). For atmospheric loading of spherical harmonic degree two, the value of k′=-0.6031 is different from that for ocean loading as k′ =-0.3052,while the latter is currently used for both cases-ocean/atmospheric loading-without distinction. We discuss(i) the amount of solid Earth tidal dissipation(which has been left most uncertain) and(ii) secular changes of the dynamical state of the Earth-Moon-Sun system. Our estimate of the solid Earth tidal torque is-4.94×10^(15) Nm.
