Nutation and the Earth’s Rotation

The lAU Symposium No. 78, "Nutation and the Earth's Rotation," was held in Y~ev, USSR, from 23 to 28 May, 1977. The Organizing Committee included E. P. Fedorov and R. O. Vicente (Joint Chairmen), W. Fricke, J. Kovalevsky, P. Melchior, N. Pariisky, M. Rochester, C. Sugawa, G. Wilkins and Ya. Yatskiv, who presided over the Local Organizing Com­ mittee. The meeting was sponsored by Commission 19 and co-sponsored by Commissions 4, 8, and 31. There were 114 registered participants from 14 countries. The main topics covered were as follows: the specification of nutation in the lAU system of astronomical constants; determination of forced nutation and nearly diurnal free polar motion from astronomical observations; expected use of lunar ranging data and long baseline interferometers for precise measurement of the nutation terms; models of the internal constitution of the Earth as the basis of a new theory of nutation; the effect of the ocean and liquid core on the rotation of the Earth; and the interaction between Earth tides and nutation.

Table of Contents:
Session I.- The Specification of Nutation in the IAU System of Astronomical Constants (Review Paper).- Some Difficulties in the Theory of Nutation.- Reduction of the Past ILS Data in a Uniform System.- For a Clear Terminology in the Polar Motion Investigations.- Discussion.- Session II.- Nutation and the Oppolzer’s Terms.- On the Effect of the Scale Value on the Principal Nutation Terms Derived from the ILS Data.- Nutation Terms Derived from the z- and the ?-Term of the IPMS System.- Fortnightly Nutation from the ILS Data.- Short-Period Nutation from Observation with the Pulkovo Polar Tube.- Short-Period Terms in Time and Latitude Observations Made with the Herstmonceux Photographic Zenith Tube.- Nearly Diurnal Free Polar Motion Derived from Astronomical Latitude and Time Observations (Review Paper).- Nutation and Nearly Diurnal Latitude Variations from the Data of Bright Zenith Star Observations in Poltava from 1950 to 1977.- Spectrum of Latitude Variations in the Frequency Range 1.4–2.2 cpy and a Search for Nearly Diurnal Free Polar Motion.- Elimination de Certains Effets dans les Observations à l’Astrolabe: Application à l’Évaluation de Corrections aux Termes Principaux de la Nutation.- Corrections to Some Terms of Nutation Deduced from the Paris Astrolabe Observations.- Recherche de Termes de Nutation dans l’Analyse des Observations de Latitude Effectuées à Paris.- A Determination of the Principal Term of Nutation.- Spectral Analysis of Latitude Observations at Gorky and Determination of the Semi-Annual Term of Nutation.- On the Adoption of Empirical Corrections to Woolard’s Nutation Theory.- Discussion.- Session III.- Expected Use of Lunar Range Data to Determine Modified Nutation Terms.- The Determination of Absolute Phase of a Long BaselineInterferometer and its Application to the Precise Measurement of the Constant of Nutation.- The Earth’s Constitution and the Nutations (Review Paper).- On the Nature of the Nonhydrostatic Quadrupole Excess Moment of the Earth.- On the Equation of Precession and Nutation of the Dynamically Unbalanced Earth (Abstract).- On the Ellipsoidal Distribution of Density in the Earth’s Interior (Abstract).- Discussion.- Session IV.- A Review of the Different Liquid Core Models Used for the Computation of the Dynamical Effects on Nutations and Earth Tides.- A Simple Theory on Dynamical Effects of Stratified Fluid Core Upon Nutational Motion of the Earth.- Gravitational, Inertial and Toroidal Oscillations of the Outer Core and Their Related Free Wobbles.- The Period of the Chandler Wobble.- A Normal Mode Study of Wobble and Nutation.- Local Effects on Earth Tide Observations.- On the Electro-Magnetic Coupling between the Core and the Mantle of the Earth.- On Random Excitation and Damping of the Polar Motion.- Variations of Differences of Latitudes and of Mean Latitudes of Stations Located in the Vicinity of a Common Meridian.- Discussion.- Session V.- Earth Tide Components and Forced Nutations (Review Paper).- Forced Nutation and Irregularity of the Rotation of the Earth.- The Love Numbers of the Anelastic Earth.- Global Plate Tectonics and the Secular Motion of the Pole.- Discussion.- Session VI.- Report of General Discussions at IAU Symposium No. 78 on Nutation and the Earth’s Rotation.- Resolutions.