Observing our Changing Earth

At the XXIV General Assembly of the International Union of Geodesy and Geophysics (IUGG), held July 2–13, 2007 in Perugia, Italy, the International As- ciation of Geodesy (IAG) also had its quadrennial General Assembly. The IAG - organized and contributed to several Union Symposia, as well as to Joint Symposia with other Associations. It also organized ve Symposia of its own, one dedicated to eachofitsfourCommissionsanda fthonededicatedtotheGlobalGeodeticObse- ing System (GGOS). This volume contains the proceedings of these ve Symposia, which are listed below: Symposium GS001: Reference Frames Convener: H. Drewes Co-convener: A. Dermanis Symposium GS002: Gravity Field Convener: C. Jekeli Co-conveners: U. Marti, S. Okubo, N. Sneeuw, I. Tziavos, G. Vergos, M. Vermeer, P. Visser Symposium GS003: Earth Rotation and Geodynamics Convener: V. Dehant Co-convener: Chengli Huang Symposium GS004: Positioning and Applications Convener: C. Rizos Co-convener: S. Verhagen Symposium GS005: The Global Geodetic Observing System (GGOS) Conveners: M. Rothacher Co-conveners: R. Neilan, H. -P. Plag The Symposia were organized based on the structure of the IAG (i. e. , one per Commission) and covered the there pillars of geodesy, namely geometry, Earth ro- tion, and gravity eld, plus their applications. The inclusion of the Symposium on GGOS – which is no longer a project but a major component of the IAG – integrated all geodetic areas and highlighted the importance of multidisciplinarity in, and for, geodetic research.

Symposium GS001 Reference Frames.- Reference Systems, Reference Frames, and the Geodetic Datum.- Investigations into a Dynamic Geocentric Datum.- On the Strength of SLR Observations to Realize the Scale and Origin of the Terrestrial Reference System.- Impact of the Network Effect on the Origin and Scale: Case Study of Satellite Laser Ranging.- Satellite Laser Ranging Biases and Terrestrial Reference Frame Scale Factor.- Status of the European Reference Frame (EUREF).- Reprocessing of a Regional GPS Network in Europe.- Latest Enhancements in the Brazilian Active Control Network.- Searching for the Optimal Relationships Between SIRGAS2000, South American Datum of 1969 and Córrego Alegre in Brazil.- The Permanent Tide In Height Systems.- Combined Adjustment of National Astro-Geodetic Network and National GPS2000 Geodetic Network.- Symposium GS002 Gravity Field.- Improved Resolution of a GRACE Gravity Field Model by Regional Refinements.- The Role of the Atmosphere for Satellite Gravity Field Missions.- Assessment of GPS-only Observables for Gravity Field Recovery from GRACE.- Detecting the Baltic Sea Level Surface with GPS-Measurements and Comparing it with the Local Geoid Model.- Strengthening the Vertical Reference in the Southern Baltic Sea by Airborne Gravimetry.- Downward Continuation of Airborne Gravimetry and Gradiometry Data Using Space Localizing Spline Functions.- The Earth’s Gravity Field Components of the Differences Between Gravity Disturbances and Gravity Anomalies.- Research on the Calibration of Onboard Accelerometer by Dynamic Method.- Current Status of Gravity Measurements in the Republic of Croatia with the Fundamental Gravity Network Finalization Project.- The Development of the European Gravimetric Geoid Model EGG07.- An Attempt for an Amazon Geoid Model Using Helmert Gravity Anomaly.- Combination of Gravimetry, Altimetry and GOCE Data for Geoid Determination in the Mediterranean: Evaluation by Simulation.- An Attempt Towards an Optimum Combination of Gravity Field Wavelengths in Geoid Computation.- BVP, Global Models and Residual Terrain Correction.- Domain Transformation, Boundary Problems and Optimization Concepts in the Combination of Terrestrial and Satellite Gravity Field Data.- Numerical Solution of the Fixed Altimetry-Gravimetry BVP Using the Direct BEM Formulation.- On the Combination of Gravimetric Quasi-Geoids and GPS-Levelling Data.- An Alternative Approach for the Determination of Orthometric Heights Using a Circular-Arc Approximation for the Plumbline.- On Evaluation of the Mean Gravity Gradient Within the Topography.- Comparison of Techniques for the Computation of a Height Reference Surface from Gravity and GPS-Levelling Data.- The Inversion of Poisson’s Integral in the Wavelet Domain.- On the Principal Difficulties and Ways to Their Solution in the Theory of Gravitational Condensation of Infinitely Distributed Dust Substance.- Representation of Regional Gravity Fields by Radial Base Functions.- Precise Gravity Time Series and Instrumental Properties from Combination of Superconducting and Absolute Gravity Measurements.- On a Feasibility of Modeling Temporal Gravity Field Variations from Orbits of Non-dedicated Satellites.- EOF Analysis on the Variations of Continental Water Storage from GRACE in China.- Influence of Hydrology-Related Temporal Aliasing on the Quality of Monthly Models Derived from GRACE Satellite Gravimetric Data.- Image Super-Resolution via Filtered Scales Integral Reconstruction Applied to GOCE Geoid Data.- An Error Model for the GOCE Space-Wise Solution by Monte Carlo Methods.- Accuracy Analysis of External Reference Data for GOCE Evaluation in Space and Frequency Domain.- Gravity Field Determination at the AIUB – The Celestial Mechanics Approach.- Robust Trend Estimation from GOCE SGG Satellite Track Cross-Over Differences.- Reference Frame Consistency in CHAMP and GRACE Earth Gravity Models.- The Fast Analysis of the GOCE Gravity Field.- GRACE Application to the Receding Lake Victoria Water Level and Australian Drought.- Updated OCTAS Geoid in the Northern North Atlantic – OCTAS07.- New Combined Geoid Solution HGTUB2007 for Hungary.- Regional Astrogeodetic Validation of GPS/Levelling Data and Quasigeoid Models.- Insights into the Mexican Gravimetric Geoid (GGM05).- An Improved Geoid in North Eastern Italy.- Towards a New Global Digital Elevation Model.- Symposium GS003 Earth Rotation and Geodynamics.- Contribution of Non-Tidal Oceanic Mass Variations to Polar Motion Determined from Space Geodesy and Ocean Data.- Simulation of Historic and Future Atmospheric Angular Momentum Effects on Length-of-day Variations with GCMs.- Contributions of Tidal Poisson Terms in the Theory of the Nutation of a Nonrigid Earth.- Consistency of Earth Rotation, Gravity, and Shape Measurements.- Current Estimation of the Earth’s Mechanical and Geometrical Parameters.- The Earth’s Global Density Distribution and Gravitational Potential Energy.- Analysis of Geophysical Variations of the C20 Coefficient of the Geopotential.- Analysis of Mass Variations in Northern Glacial Rebound Areas from GRACE Data.- Report of GGP Activities to Commission 3, Completing 10 Years for the Worldwide Network of Superconducting Gravimeters.- European Tidal Gravity Observations: Comparison With Earth Tide Models And Estimation Of The Free Core Nutation (Fcn) Parameters.- Physical Modelling To Remove Hydrological Effects At Local And Regional Scale: Application To The 100-M Hydrostatic Inclinometer In Sainte-Croix-Aux-Mines (France).- Monitoring Crustal Movement in the Qinghai-Tibetan Plateau Using GPS Measurements from 1993 to 2002.- Impact of Local GNSS Permanent Networks in the Study of Geodynamics in Central Italy.- New Results Based on Reprocessing of 13 years Continuous GPS Observations of the Fennoscandia GIA Process from BIFROST.- Analysis of GPS Data from An Antarctic Ice Stream.- Dynamic Analysis of Crustal Movements Along the Dead-Sea Rift.- Symposium GS004 Positioning and Applications.- GPS-Based Monitoring of Surface Displacements in the Mud Volcano Area, Sidoarjo, East Java.- Differential and Precise Point Positioning in the South American Region with lonosphere Maps.- Current State of Precise Point Positioning and Future Prospects and Limitations.- Nonstationary Tropospheric Processes in Geodetic Precipitable Water Vapor Time Series.- Combination of Multiple Repeat Orbits of ENVISAT for Mining Deformation Monitoring.- An Investigation into Robust Estimation Applied to Correlated GPS Networks.- Geometry-Based TCAR Models and Performance Analysis.- Real-Time Kinematic OTF Positioning Using a Single GPS Receiver.- Concept of a Multi-Scale Monitoring and Evaluation System for Landslide Disaster Prediction.- Ionospheric Modelling in the North of Algeria.- Kinematic Precise Point Positioning During Marginal Satellite Availability.- Establishing A Gnss Receiver Antenna Calibration Field in the Framework Of Probral.- Trimble’s Rtk And Dgps Solutions In Comparison With Precise Point Positioning.- The Precision And Accuracy Of Shanghai Vrs Network.- Improving the Stochastic Model of GNSS Observations by Means of SNR-based Weighting.- Evaluating the Brazilian Vertical Datum Through Improved Coastal Satellite Altimetry Data.- Land Subsidence Monitoring in Australia and China using Satellite Interferometry.- Analysis on Temporal-Spatial Variations of Australian TEC.- Use of Global and Regional Ionosphere Maps for Single-Frequency Precise Point Positioning.- Quality Control for Building Industry by Means of a New Optical 3D Measurement and Analysis System.- New Solutions to Classical Geodetic Problems on the Ellipsoid.- GNSS Carrier Phase Ambiguity Resolution: Challenges and Open Problems.- Static Stress Change from the 8 November, 1997 Ms 7.9 Manyi, Tibet Earthquake as Inferred from InSAR Observation.- Application of Computer Algebra System to Geodesy.- Crustal Velocity Field Modelling with Neural Network and Polynomials.- Next-Generation Algorithms for Navigation, Geodesy and~Earth Sciences Under Modernized Global Navigation Satellite Systems (GNSS).- Linear Combinations for Differential Radar Interferometry.- Symposium GS005 The Global Geodetic Observing System (GGOS).- Recent Progress in the VLBI2010 Development.- The Contribution of GGP Superconducting Gravimeters to GGOS.- Combine Analysis of Earth Orientation Parameters and~Gravity Field Coefficients for Mutual Validation.