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1.
本文利用Hamilton方法研究弹性地球自转运动，采用地球模型PREM参数，给出了形状轴的章动序列．结果表明我们的方法是可行的，计算是可靠的．弹性地幔对地球章动的影响仅在毫角秒量级上，它相对液核对地球竟动的影响要小得多． 相似文献
2.
In this article an approximate analytical integration is performed of the Hamiltonian corresponding to the rotational motion
of an Earth whose elastic mantle is deformed by rotation and lunisolar attraction, using Deprit's perturbation method for
the first order. Besides the usual terms, this Hamiltonian includes the perturbation of the kinetic energy and the elastic
energy produced with the deformation, as well as their causes, the tidal and the centrifugal potential; these new terms have
already been studied for the tidal deformation in previous articles (Getino and Ferrándiz, 1990a, 1990b). The effects of the
deformation due to the centrifugal potential are studied in this article, following the same method as that used for the tidal
deformation. Numerical tables of the periodic perturbations corresponding to the nutation in obliquity and longitude are obtained.
As for the secular effects, a theoretical value of 457 days is obtained for Chandler's period. 相似文献
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简要说明了天文地球动力学范畴内所研究的潮汐现象，包括由日月引潮力引起的固体潮、海洋潮、大气潮和由于地球自转轴的极移引起的极潮，以及这些潮汐对地球自转和地球自转的测量产生的效应。重点阐述中国天文学界在这一领域里的研究成果。这些研究涉及潮汐影响地球自转的机制，也就是各种潮汐效应与极移、自转速率变化和章动的关系，包括构建这类关系的理论模型，分析潮汐对它们的影响，利用中国古代丰富的天象记录计算地球自转的长期减慢，计算弹性或滞弹地球的洛夫数，依据某一地球模型计算潮汐效应或章动序列等等。研究也涉及在测量地球自转参数的不同技术中各种潮汐效应对测量结果产生的影响及其改正，并涉及与潮汐有关的观测方法的优化和数据处理过程的改进。最后介绍了中国学者所发现的脉冲星的周期和周期变率测量中的潮汐效应，尽管它们的量级甚微，但不容忽视。 相似文献
5.
Juan Getino José M. Ferrándiz 《Monthly notices of the Royal Astronomical Society》2001,322(4):785-799
In this paper we present a theory of the Earth rotation for a model composed of an inelastic mantle and a liquid core, including the dissipation in the core–mantle boundary (CMB). The main features of the theory are: (i) to be Hamiltonian, therefore the computation of some complex inner torques can be avoided; (ii) to be self-consistent and non-dependent on a previous rigid Earth theory, so there is no need to use transfer functions; (iii) to be analytical, the solution being derived by perturbation methods. Numerical nutation series deduced from the theory are compared with the IERS 96 empirical series, an accuracy better than 0.8 mas in providing celestial ephemeris pole (CEP) offsets . 相似文献
6.
Starting from the Hamiltonian model for a solid Earth with an elastic mantle previously developped by the authors, analytical expressions are derived which give the nutation series corresponding to the plane perpendicular to the angular momentum vector, to the plane perpendicular to the rotational axis and to the equator of figure, as well as the series that give the polar motion. The effects of the different perturbations — solid Earth, centrifugal and tidal potentials — are calculated separately. The corrections due to the elasticity of the mantle, which mostly correspond to the Oppolzer terms, are calculated with an accuracy of 10–6 arc sec., given that the intrinsic observational accuracy has reached 0.01 mas. 相似文献
7.
地球动力学扁率及其与岁差章动的关系 总被引：5，自引：0，他引：5
由岁差常数求得的日月岁差是天文学的重要参数之一,它和地球动力学扁率相联系。地球动力学扁率在章动理论的计算中也是一个重要的物理量。介绍了由不同的观测方法和模型给出的地球动力扁率值,并讨论了它也岁差的关系和对章动计算的影响。在刚体地球章动振幅的计算中,地球动力学扁率值起着尺度因子的作用,要改善刚体地球章动振幅的计算,需要修改目前的黄经总岁差值。非刚体地球章动的转换函数中所采用的简正模和常数都直接或间接地依赖地球动力学扁率值。在IAU1980章动理论中,计算刚体地球章动振幅所使用的地球动力学扁率值计算转换函数中简正模频率和常数所使用的地球动力学扁率值并不一致。随着观测和计算精度的提高,地球动力学扁率值的不一致将影响章动振幅的计算。在建立刚体地球章地动理论中,如何解释地球动力学扁率值的差异,如何选取地球动力学扁率值,还有待进一步的研究。 相似文献
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In this article, our previous Hamiltonian theory for the rotation of an Earth whose elastic mantle is deformed by rotation and linisolar attraction is applied to the study of the secular acceleration of the Earth's rotation. Since it is a result of the inelasticity, the theory is extended to include a phase lag. So, we obtain, in a theoretical way, a value of –5.6 × 10–22 rd sec–2, which agrees perfectly with the latest observational results. 相似文献
10.
In this paper we present a new symbolic processor specially suited for the Earth rotation theory. This processor works with a more general kind of Poisson series called Kinoshita series, which has resulted to be very useful in the Earth rotation theory. Its structure is adapted for dealing with the more general analytical expressions that appear in the Earth rotation theory. This new algebraic processor has been successfully used for computing different contributions to the nutation series of the rigid Earth.This revised version was published online in October 2005 with corrections to the Cover Date. 相似文献
11.
Accurate Analytical Calculation of Effects of Rorations of the Central Planet on a Staellite's Orbit
Sergey M. Kudryavtsev 《Celestial Mechanics and Dynamical Astronomy》1997,67(2):131-144
Satellite orbital perturbations due to many rotations of the planet-fixed reference frame are calculated by a general analytical
method. For the International Terrestrial Reference Frame (ITRF) the effects of the Earth irregular rotation, precession,
nutation, and polar motion are considered. Gravity coefficients of the Earth potential expansion are expressed in an inertial
Celestial Reference Frame (CRF) as functions of the set of standard constant coefficients derived in the ITRF and of the rotation
angles between the CRF and ITRF. The analytical motion theory uses time dependent gravity coefficients, and the Lagrange motion
equations are integrated in the CRF, as it is done by numerical methods. Comparison of the proposed analytical method with
a numerical one is presented. Motion of the ETALON-1 geodetic satellite perturbed by the geopotential (36*36) and by the full
effects of the Earth irregular rotation, precession, nutation and polar motion is predicted. The r.m.s. difference between
the satellite's coordinates calculated by both methods over a year interval is 2 cm.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
12.
Yoshio Kubo 《Celestial Mechanics and Dynamical Astronomy》2009,105(4):261-274
We calculate the so-called convective term, which shows up in the expression for the angular velocity of the elastic Earth,
within the Andoyer formalism. The term emerges due to the fact that the elasticity-caused perturbation depends not only on
the instantaneous orientation of the Earth but also on its instantaneous angular velocity. We demonstrate that this term makes
a considerable contribution into the overall angular velocity. At the same time the convective term turns out to be automatically
included into the correction to the nutation series due to the elasticity, if the series is defined by the perturbation of
the figure axis (and not of the rotational axis) in accordance with the current IAU resolution. Hence it is not necessary
to take the effect of the convective term into consideration in the perturbation of the elastic Earth as far as the nutation
is related to the motion of the figure axis. 相似文献
13.
When the problem of the rotation of a non-rigid body is studied, the usual procedure consists of adding perturbations to the Hamiltonian of the rigid solid. In some cases, as occurs with the centrifugal deformation, the new perturbations contains potentials which depend on the velocity, but usually one alter neither the definition of the canonical variables nor the method for obtaining the Hamiltonian. Although this procedure gives good estimates and its formulation is simpler, it is incorrect from a theoretical point of view.In this paper we rigorously develop a Hamiltonian formulation of the problem, considering potentials that depend on the velocity. Thus the differences between the two procedures are clearly shown, giving special emphasis to the case of the elastic Earth, for which we show that the differences obtained cannot be ignored within the accuracy limits at present required. 相似文献
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In this paper the tidal phenomena on the Earth are concisely specified, including solid tides, ocean tides and atmospheric tides due to the luni-solar tide-generating force, and the Earth pole tide due to the motion of the Earth's rotation axis (polar motion); as well as their effects on the Earth rotation. The outcomes of scientific researches of Chinese astronomers on these topics are described in some detail. These researches deal with the mechanisms responsible for tidal effects on the earth rotation, and on the measurements of the Earth rotation parameters. Finally, the effects discovered by Chinese researchers on the measurements of the period and change in period of pulsars are discussed. These effects are very small in magnitude but not negligible. 相似文献
16.
This paper is the first of a set of four, in which we shall develop the first part of a project dedicated to elaborating a Hamiltonian theory for the rotational motion of a deformable Earth. Here we study only the perturbation due to the deformation of the elastic mantle by tidal body force. In the present paper, we define two canonical systems of variables—we give these variables the names of elastic variables of Euler and Andoyer respectively. Next, using them, we obtain the canonical expression of rotational kinetic energy, which is valid for any Earth model satisfying hypotheses as general as those established in Section 2. 相似文献
17.
Juan Getino 《Celestial Mechanics and Dynamical Astronomy》1995,61(1):21-49
Continuing the study of the rotation of a deformable Earth begun by Getino and Ferrandiz (1990, 1991a, 1991b, 1993, 1994) for an Earth model with an elastic spherical mantle, in this paper on one hand we deal with the effect of the ellipticity, and on the other hand, we include the toroidal solution of the displacement vector. Taking an axis symmetrical, slightly ellipsoidal Earth, the modification due to the ellipticity is introduced into the solution of the displacement vector for both spheroidal and toroidal modes, and, after defining the adequate variables, we give the canonical formulation of the corresponding increase in the kinetic energy. 相似文献
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Yoshio Kubo 《Celestial Mechanics and Dynamical Astronomy》2011,110(2):143-168
Under perturbations from outer bodies, the Earth experiences changes of its angular momentum axis, figure axis and rotational
axis. In the theory of the rigid Earth, in addition to the precession and nutation of the angular momentum axis given by the
Poisson terms, both the figure axis and the rotational axis suffer forced deviation from the angular momentum axis. This deviation
is expressed by the so-called Oppolzer terms describing separation of the averaged figure axis, called CIP (Celestial Intermediate
Pole) or CEP (Celestial Ephemeris Pole), and the mathematically defined rotational axis, from the angular momentum axis. The
CIP is the rotational axis in a frame subject to both precession and nutation, while the mathematical rotational axis is that
in the inertial (non-rotating) frame. We investigate, kinematically, the origin of the separation between these two axes—both
for the rigid Earth and an elastic Earth. In the case of an elastic Earth perturbed by the same outer bodies, there appear
further deviations of the figure and rotational axes from the angular momentum axis. These deviations, though similar to the
Oppolzer terms in the rigid Earth, are produced by quite a different physical mechanism. Analysing this mechanism, we derive
an expression for the Oppolzer-like terms in an elastic Earth. From this expression we demonstrate that, under a certain approximation
(in neglect of the motion of the perturbing outer bodies), the sum of the direct and convective perturbations of the spin
axis coincides with the direct perturbation of the figure axis. This equality, which is approximate, gets violated when the
motion of the outer bodies is taken into account. 相似文献
20.
We perform a complete reconstruction of the series of the nutation for a rigid Earth model with the use of the very accurate
theories ELP2000 and VSOP82 for the motion of the Moon and the planets respectively, in such a way that all the individual
contributions up to 0.005 mas should be taken. This implies the introduction of the planetary effects, of the influence of
second-order parts of the potential of the Earth (J3, triaxiality), and some improvements due to an extension of the theory
at the second order. All this increase notably the number of coefficients to be taken in account, and modifies also in a significant
way the value of some of them. 相似文献