Based on an international symposium held in Tokyo, the volume combines papers in the fields of gravity, geoid and marine geodesy. Special emphasis is placed on the use of gravity in modeling tectonic processes and the problems of geophysical inversion. In addition, absolute and relative gravity measurement in static and airborne mode, satellite altimetry, geopotential modeling, and global geodynamics are dealt with. The field of marine geodesy includes contributions on sea level change, seafloor deformation and mapping, sea surface positioning, electronic charting, and datum transformations.
Based on the IAG scientific assembly in Rio de Janeiro, Brazil, this volume combines papers in the fields of gravity and geoid, geodynamics, and geodesy in Antarctica. The volume contains papers on recent progress in absolute and relative gravimetry, on models of the global gravity field, theoretical developments in physical geodesy, and many examples of regional gravity field and geoid models. Geodynamics chapters include papers on earth rotation and geopotential variations, reference frames and global deformations, as well as a section on the combination of space and terrestrial methods for deformation observations. The current status of geodesy in Antarctica is illustrated by a number of papers.
This symposium continued the tradition of mid-term meetings held between the joint symposia of International Geoid and Gravity Commissions. This time, geodynamics was chosen as the third topic to accompany the traditional topics of gravity and geoid. The symposium thus aimed at bringing together geodesists and geophysicists working in the general areas of gravity, geoid and geodynamics. Besides covering the traditional research areas, special attention was paid to the use of geodetic methods for geodynamics studies, dedicated satellite missions, airborne surveys, geodesy and geodynamics of arctic regions, and the integration of geodetic and geophysical information.
These proceedings represent the worldwide picture of the state of the art of geodesy. The volume comprehensively covers the most recent results and supplies a good review of the new ideas developing in the field, opening a window to the future of geodesy.
In this volume, the state of the art in geodesy is presented with special emphasis on the challenges of the next decade. It is subdivided into six parts. The first five parts discuss the challenges of providing a stable global reference at the parts per billion level by space methods, the impact of recently approved dedicated satellite missions on the determination of a high resolution global gravity field and its refinements by airborne gravity, advances in geodynamics and their impact on the monitoring of seismic hazards and earthquake prediction, the increasing use of GPS and INS in kinematic mode for mapping the Earth's surface and monitoring the behaviour of large man-made structures, and the related advances in mathematical theory and numerical techniques. The last part is dedicated to the discussion of a new structure for IAG to meet these challenges.
The Symposium on Vertical Reference Systems (VeReS) was initiated on the occasion of the XXII General Assembly of the International Union of Geodesy and Geophysics (IUGG), Birmingham 1999, by Professor Dr. Wolfgang Torge, Past President of the International Association of Geodesy (lAG) and representative of lAG to the Pan-American Institute of Geography and History (PAIGH). The idea was to organise another joint symposium of lAG and PAIGH like the previous one held during the XX IUGG General Assembly at Vienna, Austria, in 1991. Good reasons for such a joint symposium were the great success and the ongoing activities of the Project on the South American Geocentric Reference System (Sistema de Referencia Geocentrico para America del Sur, SIRGAS) being sponsored by lAG and PAIGH since 1993. The SIR GAS Project (Working Group I) had presented a continental South American reference frame of 58 stations during the lAG Scientific Assembly at Rio de Janeiro, in 1997. This reference frame was already adopted by several South American countries as the basis for their new national horizontal geodetic datums (SIRGAS Working Group II). To overcome the problems of the heterogeneous vertical (height) datums between the individual countries, SIRGAS had installed its Working Group III "Vertical Datum" in 1997. As the discussion on the unification of vertical reference systems is also going on in lAG and other bodies of science and practice, it was decided to dedicate the symposium to this topic.
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.
