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Note on the Determination of the Neaely Diurnal Free Nutation (Core Nutation) and the Principal Term of Nutation Based on the Astrometric Data

Published online by Cambridge University Press:  12 April 2016

Ya.S. Yatskiv  and
L.D. Kovbasyuk
Ya.S. Yatskiv
Affiliation:
The Main Astronomical Observatory of the Ukrainian SSR Academy of Sciences Kiev, USSR
L.D. Kovbasyuk
Affiliation:
Department of the All-union Astronomy and Geodesy Society Niznij Novgorod, USSR

Extract

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Due to the highly accurate determination of the corrections to the nutation terms (the IAU-1980 nutation theory) by VLBI observations, the proposal for adoption of the new nutation theory or standard model of nutation is being discussed. At this point there are two unsolved problems:

  1. (a) VLBI observations can’t provide reliable estimates of the principal nutation term. The reason is that the correlation between this term and the precession constant is high due to the insufficient time span of these observations (about 10 years).

  2. (b) period of free core nutation (FCN) which depends on the ellipticity of the mantle-core boundary has not been, so far, reliably determined from direct observations.

In the present paper, we would like to draw attention to the results of the analysis of astrometric latitude and time observations which could be useful for resolving these problems.

Type
Part 2. Poster Papers
Information
International Astronomical Union Colloquium , Volume 127: Reference Systems , 1991 , pp. 385 - 391
Copyright
Copyright © United States Naval Observatory 1991

References

Capitaine, N., Li, Z.X. and Nie, S.Z. 1988, Determination of the principal term of nutation from improved BIH astrometric data, Astron. Astrophys. 202, 306–308.Google Scholar
Charlot, P., Sovers, O.J., Williams, J G., Newhall, X X 1990, A global VLBI/LLR analysis for the determination of precession and nutation constants presented at the 18th NASA CDP meeting, Pasadena, Ca.,USA.Google Scholar
Dehant, V. 1988, Core undertones in an elliptical uniformly rotating Earth, Observatoire Royal Belgique, Communications Serie A, No. 92, 29–34.Google Scholar
Glebova, L.A., Kostina, L.D., Malkin, Z.M. and Persiyanova, N.R., 1990, The determination of the principal nutation terms from the observations with ZTF-135 in 1948.7-1989.0. In Proc. IAU Symp. 141 “Inertial Coordinate System on the Sky”. Lieske, J.H. and Abalakin, V.K. (Eds). Kluwer Publ. 153–154.CrossRefGoogle Scholar
Kovbasyuk, L.D. 1984, On the global nature of the nearly diurnal latitude variation spectrum, Soviet Astronomy, 61, 6, 1218–1225.Google Scholar
Kovbasyuk, L.D. 1985, On the study of the parameters of the Earth’s nearly diurnal free nutation based on latitude observation, Soviet Astronomy, 62, 2, 385–391.Google Scholar
Kovbasyuk, L.D. 1988, Comparison of spectra of nearly diurnal latitude variations in Poltava and Gorky, In Proc. of the 2nd Orlov Conference, Kiev, Naukova Dumka, 134–137 (in Russian).Google Scholar
Lapaeva, V.V. 1988, Determination of the nutation coefficients from latitude observation in AOE, In Proc. of the 2nd Orlov Conference, Kiev, Naukova Dumka, 10–13 (in Russian).Google Scholar
Melchior, P.J., Crossley, D.J., Dehant, V.P. and Ducarme, B. 1988, Have inertial waves been identified from the Earth’s core? Observatoire Royal Belgique, Communication Serie A, No. 91, 1–12.Google Scholar
Popov, N.A. and Yatskiv, Ya.S. 1979, Nutation and nearly diurnal latitude variations from the data of bright zenith star observations in Poltava from 1950 to 1977, in Proc. IAU Symp. No. 78 “Nutation and the Earth’s rotation”, Fedorov, E.P., Smith, M.L. and Bender, P.L. (Eds), D. Reidel, Dordrecht, Holland.Google Scholar
Yatskiv, Ya.S., Wako, Ya. and Kaneko, Yo., 1975, Study of the nearly diurnal free nutation based on latitude observations of the ILS stations. Publ. Intern. Lat. Obs. Mizusawa, 10, 1, 1–31.Google Scholar
Yatskiv, Ya.S. 1979, Nearly diurnal free polar motion derived from astronomical latitude and time observations, In Proc. IAU Symp. No. 78 “Nutation and the Earth’s rotation”, Fedorov, E.P., Smith, M.L. and Bender, P.L. (Eds), D. Reidel, Dordrecht, Holland.Google Scholar
Yatskiv, Ya.S. 1980, Nutation in the system of astronomical constants., Preprint of ITR-80-95p, Kiev, 1980, 60pp, (in Russian).Google Scholar
Yatskiv, Ya.S. 1989, Contemporary problems of the Earth rotation study, In “Problem of construction of coordinate system in astronomy”, Leningrad, 162–176, (in Russian).Google Scholar