Earth Rotation: Solved and Unsolved Problems

The idea for organl.zl.ng an Advanced Research Workshop entirely devoted to the Earth rotation was born in 1983 when Professor Raymond Hide suggested this topic to the special NATO panel of global transport mechanism in the Geosciences. Such a specialized meeting did not take place since the GEOP research conference on the rotation of the Earth and polar motion which was held at the Ohio State University (USA) in 1973. In the last ten years, highly precise measurements of the Earth's rotation parameters and new global geophysical data have become available allowing major advance to be made in the under standing of the various irregularities affecting the Earth's rotation. The aim of the workshop was to bring together scientists who have made important contributions in this field during the last decade both at the observational and geophysical interpretation levels. The confe rence was divided into four main topics. The first session was dedicated to the definition, implementation and maintenance of the terrestrial and celestial reference systems. A few critical points have been identified as requiring further improvements: (i) appro priate selection of terrestrial sites recognized for their long term stability, (ii) determination of the relationship between terrestrial and celestial references systems as well as between the various terrestrial ones, (iii) improvment of the theory of a rotating elastic earth (the recently adopted theory needs already some corrections').

Inhalt
References Systems and Observation of the Earth's Rotation Parameters.- Celestial Reference Systems.- The Conceptual and Conventional Definitions of the Earth Rotation Parameters.- How to Measure the Earth Rotation.- Polar Motion and Signal Processing.- Accurate Earth Orientation Time Series from VLBI Observations.- Historical and Paleoobservations of the Earth's Rotation Secular Variations.- Observations of Secular and Decade Changes in the Earth's Rotation.- Earth Rotation and Solid Tides.- Tidal and Non Tidal Acceleration of the Earth's Rotation.- Global Climatic Changes and Astronomical Theory of Paleoclimates.- Short Term Atmospheric and Oceanic Effects.- Meteorological Data for Earth Rotation Studies.- High Accuracy Earth Rotation and Atmospheric Angular Momentum.- The El-Nino, the Southern Oscillation and the Earth Rotation.- The Atmospheric Circulation, the Earth's Rotation and Solar Activity.- Ocean-Atmosphere Coupling and Short Term Fluctuations of Earth Rotation.- The Damping of the Chandler Wobble and the Pole Tide.- Mantle and Core Effects.- The Influence of Earthquakes on the Polar Motion.- Flow in the Fluid Core and Earth's Rotation.- Electromagnetic Core-Mantle Coupling.- Global Earth Models and Earth Rotation.- Resonance Effects of the Earth's Fluid Core.- Long Period Core Dynamics.- Recommendations.