Over the past ten years, since the MERIT project began in 1980, great changes have taken place and significant advances made in the area of Earth Rotation and Coordinate Reference Frames. Symposium 105, held at the 125th Anniversary Meeting of the International Association of Geodesy, August 1989, was devoted to this subject. Major improvements in techniques, such as VLBI and laser ranging, have been accompanied by corresponding improvements in data-processing procedures and theories of relevant phenomena. The papers included in this volume provide both a comprehensive record of past discoveries and a sound basis for further advances. Section headings are as follows: - Earth Rotation: Determination and Prediction - Earth Rotation: Interpretation - Reference Frames

Inhalt
and Program.- Earth Rotation: Determination and Prediction.- Accuracy of the Determination or Prediction of Earth Orientation Parameters.- Earth Orientation Determinations: Some Tests of Consistency.- The ZIPE Solution for the Earth's Rotation Parameters and Some Accuracy Estimations.- Satellite Laser Ranging and Orbit Determination at Nottingham University.- Universal Time Prediction Using Both Geodetic and Atmospheric Angular Momentum Data.- Prediction of Polar Motion by Least-Squares Collocation.- Polar Motion Prediction by the Least-Squares Collocation Method.- Earth Rotation: Interpretation.- Atmospheric Excitation of the Earth's Rotation.- The Earth-Atmosphere Momentum Budget: Remaining Discrepancies at High and Low Frequencies.- Air and Water Contributions to Polar Motion Excitation.- On Polar Motion Equations Applied for Analysis of the Short Term Atmospheric Excitation.- A 3060 Day Oscillation in Length-of-Day and Atmospheric Angular Momentum: Extratropical Origin?.- Origin of the 3060 Day Oscillation in the LOD and Atmospheric Angular Momentum: New Findings from the UCLA General Circulation Model.- A 120-Day Oscillation in Solar Activity and Geophysical Phenomena abstract only.- Numerical Analysis of Earth Rotation and Atmospheric Angular Momentum Parameters.- Reference Frames.- Definition of a Terrestrial Reference Frame Using IRIS VLBI Observations: Approaching Millimeter Accuracy.- Contribution of SLR to Earth Rotation and Terrestrial Reference Frames.- Global Station Coordinates and Earth Rotation Parameters from LAGEOS Laser Ranging.- The IERS Terrestrial Reference Frame abstract only.- The Optimum Conventional Terrestrial System Determined by VLBI and SLR Stations.- The Secular Drift of the Rotation Pole.- The Use of the Celestial PoleCoordinates in the Transformation Between the Celestial and Terrestrial Reference Frames.- Space VLBI: A New Technique for Unification of Reference Frames.- Author Index.