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1.
Summary Whereas observations of planets and solar satellites are more promising for detecting possible variations of Newtonian gravitational constant,G, with time the application of additional methods which are substantially different might be useful. It is discussed to what extent the tidal problems can be solved in connection with lunar orbit tracking for detectingG; further a relativeG-experiment at the earth surface is outlined. 相似文献
2.
The transition from local horizon and terrestrial BIH-systems to celestial reference frames is well known to be affected by various geodetic parameters such as polar motion (xp(t), yp(t)), UT1-TUC (where UT1 is basically dependent on variations in UT0 and t=time), plumb line deflections (, ) of observation stations, global and local tidal deformations etc. Variations of such quantities with (relative) resolution of the order of 0.001 and better, such as VLBI, demand the application of continuous high-precision (world-wide) geodynamic surveys whenever global theories and sufficient models are not available and the introduction of improved local and global models (geophysical and relativistic) is needed in order to match astrometric observations related to different reference frames. Prediction of parameters for immediate transformation from one system of reference into the other is sometimes of interest.The paperreviews recent results of different observations,points out a number of still open and unresolved problems in observations and modeling, anddiscusses related consequences. Conclusions for geodynamics drawn from comparison of observed data with models based on astronomical and geophysical observations give way to new understanding of basic phenomena of relevance for various disciplines. 相似文献
3.
Dipl. Ing. Erwin Groten 《Pure and Applied Geophysics》1963,56(1):1-15
Zusammenfassung Vergleicht man die infolge der Gezeitenkräfte an der Erdoberfläche auftretenden Neigungen mit den theoretisch für eine elastische Erde zu erwartenden Deformationen, so zeigt sich, daß die Differenz aus beiden — die sogenannte Residualbewegung — die für die jeweilige Gezeitenstation charakteristische Eigenbewegung darstellt. Sie enthält als wesentlichen Anteil die ozeanischen Wirkungen. Subtrahiert man daher von den Residualbewegungen diese maritimen Gezeiteneinflüsse, so ergeben sich die infolge der lunisolaren Attraktionskräfte auftretenden lokalen Verbiegungen der Erdkruste. Ein Vergleich der in europäischen und asiatischen Horizontalpendelstationen gemessenen Deformationen deutet außerdem auf einen engen Zusammenhang zwischen Residualbewegungen und Tektonik hin.
Summary A comparison of the tilts excited by tidal forces on the surface of the earth and the theoretical tilts of an elastic earth shows that the difference of both, called the residual movements, represent a caracteristic local deformation of the corresponding observation station. By subtracting the influence of ocean tides from these residuals remain the special local deformations of the earth crust by direct tidal attraction forces. The results of the observations of different stations in Europe and Asia indicate a good agreement between those residuals and the tectonic structure of the crust.相似文献
4.
The value of the Earth's rotational angular velocity determined from observations is given in the GCRS (geocentric celestial
reference system) defined by Resolution B1 of the 2000 IAU General Assembly. The same quantity derived from dynamical theories
of the Earth's rotation, such as SMART97, is referred to the␣DGRSC (dynamically non-rotating ecliptical reference system).
The relativistic theory of reference systems (RSs) enables unambiguous general-relativity relations between these quantities
to be derived.
Received: 9 November 2000 / Accepted: 9 July 2001 相似文献
5.
Summary Based on the 127th Colloquium Report of the subgroup on coordinate frames and origins of the IAU working group on reference
systems, in this paper, the possibility of taking the Celestial Departure Point as the origin of right-ascension on the instantaneous
true equator is analysed in view of high-precision geodesy and astrometry. The properties and the applications of the celestial
and terrestrial departure points in various aspects of practice and theory are generally reviewed. We have found that, referred
to the ideal barycentric reference system proposed in the 127th IAU Colloquium, the Celestial Departure Point of a Quasi-Inertial
Geocentric Equatorial Coordinate System may be a matchable origin on the moving geocentric true equator.
Presented at the Seminary on Physical Geodesy, Faculty of Mathematics and Physics of the Charles' University, Prague, March
1993; Contribution to the Special Commission on Fundamental Constants of the I.A.G.
On leave from Shanghai Observatory, China 相似文献
6.
7.
E. Groten 《Journal of Geodesy》1970,44(2):169-181
Summary The spherical harmonics development of the gravitational potential at the earth's surface and on the geoid is discussed. First,
the effect of Kelvin transformations is studied; secondly, numerical information as obtained from satellite and other data
is investigated.
Institut für astronomische und physikalische Geod?sie, Publ. No. 66, Techn. Hochschule, Munich. 相似文献
8.
9.
On the dynamical effects of a heterogeneous and compressible liquid core in the theory of Chandler wobble 总被引：1，自引：0，他引：1
The general 3-D scalar equations of motion of the liquid core (with respect to the radial components of displacements and cubic dilatation) are constructed as a superposition of the solutions of ordinary differential equations describing the dynamics of a stably stratified, heterogeneous, compressible and inviscid rotating fluid inside thin spherical layers ( Molodensky & Sasao 1995 ). The estimation of dynamical effects of a homogeneous and incompressible liquid core on the Chandler period (Groten, Lenhardt & Molodensky 1991) is generalized for the case of a heterogeneous, compressible, inviscid and neutrally stratified liquid core. 相似文献
10.
Abstract The combined use of Global Positioning System (GPS) differential positioning as well as ERS‐1 altimeter data is considered in implementing geodetic vertical datums and their unification. The article describes concepts, techniques, practical realization, and associated questions and problems. Particular aspects in view of small sea surface perturbations in offshore areas in determining sea surface components (variable and steady state) are discussed. The combinations of tide gauge data with altimetry and (mainly) GPS positioning for geodetic purposes are discussed in detail. Special attention is devoted to the associated reference systems as well as to the combination of dynamic (level and nonlevel surfaces) with geometric quantities. The discussion is based on a specific ERS‐1 project supported by the National Science Foundation. Implications and practical impact of the project are outlined. 相似文献