On the dynamical effects of a heterogeneous and compressible liquid core in the theory of Chandler wobble

Molodensky, S. M.; Groten, E.

doi:10.1046/j.1365-246x.1998.00615.x

Cited by 8 publications

(2 citation statements)

References 7 publications

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“…An exposition of the two above-described approaches is given in the papers cited above, and we will not consider them in detail. Instead, we will dwell on the technique of solving the problem based on the representation of oscillations in the rotating inhomogeneous, gravitating fluid as a superposition of solutions to the generalized Laplace tidal equations, which describe the oscillations of a thin spherical fluid shell with movable boundaries Sasao, 1995a, 1995b;Molodensky and Groten, 1996, 1998a, 1998b.…”

Section: Solutions To the Tidal Dynamical Equations For A Compositionmentioning

confidence: 99%

Tides and nutation of the Earth: II. Realistic models of the liquid core

Molodensky

2005

Sol Syst Res

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In the first part of this study (Molodensky, 2004; hereinafter, paper I), a survey of the theory of tides and nutation of the Earth was given with the inclusion of the dynamical effects of the elastic mantle and liquid core in the framework of a very simple model of a homogeneous, incompressible core. Here, effects of the inhomogeneity, compressibility, and viscosity of the liquid core are considered, along with those of electromagnetic coupling of the liquid core with the mantle and solid inner core. Errors in the present-day measurements of the amplitudes of forced nutation (of the order of 20 arc µ s) are well below not only the dynamical effects of the Earth's liquid core but also the effects of the inelasticity of the mantle, the dynamical effects of the solid inner core, and the possible effects of electromagnetic coupling between the liquid core, solid inner core, and mantle. This opens up new avenues for astrometric studies of the mechanical properties and electrical conductivity of the mantle and solid inner core at very low frequencies. The modern data on the amplitudes and phases of the Earth's forced nutation cannot be interpreted entirely unambiguously, since the following factors remain unknown: (i) the role of the core-mantle electromagnetic coupling compared to the coupling due to core viscosity near the core-mantle boundary and (ii) the frequency dependence of the creep function of the mantle at low frequencies. In large measure, the effects of electromagnetic and viscous coupling can be separated if highprecision data on the tidal variations in the gravitational force at periods of about a day are invoked and allowances are made for the differences between the effects of viscous and electromagnetic coupling on the amplitudes and phases of forced nutation and on the tidal variations in the gravitational force. Here, ranges of possible values of the creep function are constructed for periods from one hour to one day; for these calculations, values consistent with the entire set of data on the forced nutation of the Earth are assumed for the effective dynamical flattening of the liquid core-mantle and liquid core-solid inner core boundaries (these values describe the ellipticity of the boundaries of the inner core, outer core, and mantle, as well as the electromagnetic coupling between the liquid core, mantle, and solid inner core).

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Section: Solutions To the Tidal Dynamical Equations For A Compositionmentioning

confidence: 99%

Tides and nutation of the Earth: II. Realistic models of the liquid core

Molodensky

2005

Sol Syst Res

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“…The motions with amplitudes of approximately 20 mas are apparently real as they have been detected with both optical and independent modern techniques. Figure 7 displays this component of polar motion (Greiner-Mai 1997, Molodensky and Groten 1998, Pan 1999.…”

Section: Analysis Of Observational Datamentioning

confidence: 99%

Polar Motion — An Overview

McCarthy¹

2000

International Astronomical Union Colloquium

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After one hundred years of intensive study, some aspects of polar motion remain poorly understood. This motion of the Earth’s axis of rotation with respect to its mantle and crust has been observed and studied since the creation of the International Latitude Service. Research has shown that the motion of the pole is quite complicated and distinguished by components over all time scales. Observationally, the secular, Chandler and annual components of polar motion are well documented, and various geophysical processes have been suggested as likely causes. Other components such as the approximately thirty-year motion, the high-frequency motion and the daily/sub-daily motion remain as subjects of extensive research.

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Tides and nutation of the Earth: II. realistic models of the liquid core

Molodensky

2005

Sol Syst Res

View full text Add to dashboard Cite

On the dynamical effects of a heterogeneous and compressible liquid core in the theory of Chandler wobble

Cited by 8 publications

References 7 publications

Tides and nutation of the Earth: II. Realistic models of the liquid core

Tides and nutation of the Earth: II. Realistic models of the liquid core

Polar Motion — An Overview

Tides and nutation of the Earth: II. realistic models of the liquid core

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