Christoph Reigber - Böcker

The German research satellite CHAMP had been launched in summer 2000. Its modern instruments and near Earth orbit allow for the first time to collect data of the gravitational and magnetic fields and in addition to sound out the atmosphere and ionosphere by using GPS techniques. The book is the result of the first meeting of the international CHAMP research groups gathering 18 months later at the GeoForschungsZentrum Potsdam. Besides technical information the volume offers a comprehensive overview over the use of CHAMP data for Earth System Research in the fields of Geodesy, Geophysics and Meteorology.

In the summer of 2000 the German geo-research satellite CHAMP was launched into orbit. Its innovative payload arrangement and the low initial orbit allow CHAMP to simultaneously collect and almost continuously analyse precise data relating to gravity and magnetic fields at low altitude. In addition, CHAMP also measures the neutral atmosphere and ionosphere using GPS techniques. Three years after launch, more than 200 CHAMP investigators and co-investigators from all over the world met at the GeoForschungsZentrum in Potsdam to present and discuss the results derived from the  extensive data sets of the mission. The main outcome of this expert meeting is summarized in this volume. The book offers a comprehensive insight into the present status of the exploitation of CHAMP data for Earth system research and practical applications in geodesy, geophysics and meteorology.

In the recent years, space-based observation methods have led to a subst- tially improved understanding of Earth system. Geodesy and geophysics are contributing to this development by measuring the temporal and spatial va- ations of the Earth’s shape, gravity ?eld, and magnetic ?eld, as well as at- sphere density. In the frame of the GermanR&D programmeGEOTECHNO- LOGIEN,researchprojectshavebeen launchedin2002relatedto the satellite missions CHAMP, GRACE and ESA’s planned mission GOCE, to comp- mentary terrestrial and airborne sensor systems and to consistent and stable high-precision global reference systems for satellite and other techniques. In the initial 3-year phase of the research programme (2002-2004), new gravity ?eld models have been computed from CHAMP and GRACE data which outperform previous models in accuracy by up to two orders of m- nitude for the long and medium wavelengths. A special highlight is the - termination of seasonal gravity variations caused by changes in continental water masses. For GOCE, to be launched in 2006, new gravity ?eld analysis methods are under development and integrated into the ESA processing s- tem. 200,000 GPS radio occultation pro?les, observed by CHAMP, have been processed on an operational basis. They represent new and excellent inf- mation on atmospheric refractivity, temperature and water vapor. These new developments require geodetic space techniques (such as VLBI, SLR, LLR, GPS) to be combined and synchronized as if being one global instrument.

The investigation of the kinematics and dynamics of the Earth has achieved remarkable progress in the last decades enabling to understand and to explain for the first time a large variety of geodynamical, geophysical and geological phenomena. Besides the interdisciplinary geoscientific investigations the impact of increasingly precise geodetic space-time measurements and analyses have much contributed to these results. The series of symposia Geodesy and Physics of the Earth have been dedicated to these problems since the beginning. Whereas the first symposium of this series was held in 1970 on the occasion of the centenary of the foundation of the former Royal Prussian Geodetic Institute (in Berlin), the 7th symposium was celebrated in October, 1992, on the occasion of the looth anniversary of geodetic research on the Telegrafenberg in Potsdam. The 7th International Symposium Geodesy and Physics of the Earth - the lAG Symposium No. 112 - was organized by the recently created GeoForschungsZentrum (GFZ) Potsdam together with the International Association of Geodesy (lAG).It was further co-sponsored by the Deutsche Forschungsgemeinschaft, Deutsche Geodatische Kommission and the Ministerium fur Wissenschaft, Forschung und Kultur of the state of Brandenburg. As contributions of geodesy to the interdisciplinary investigation of geodynamics a total of 142 papers were presented and discussed, 108 of them are included in this publication. Besides General Aspects the presentations are divided into four main topics.

Within the national German geoscientific research and development programme "GEOTECHNOLOGIEN", funded by the Federal Ministry of Education and Research (BMBF) and the German Research Foundation (DFG), the research theme "Observation of the System Earth from Space" was selected as one of 13 key areas in this programme. During the first research phase for this theme from 2002 to 2004 six projects were accomplished covering Earth gravity field and Earth rotation research. These six projects are related to the data exploitation and preparation of analysis techniques for the gravity field satellite missions CHAMP, GRACE and GOCE, to the integration of geodetic observation techniques for a user centre within the International Earth Rotation Service and to improvements in observation and analysis techniques for airborne gravimetry and ring lasers. This book provides a detailed summary of the obtained results, which are relevant for a broad scientific community working in gravity field and Earth rotation research.

In the summer of 2000 the German geo-research satellite CHAMP was launched into orbit. Its innovative payload arrangement and the low initial orbit allow CHAMP to simultaneously collect and almost continuously analyse precise data relating to gravity and magnetic fields at low altitude. In addition, CHAMP also measures the neutral atmosphere and ionosphere using GPS techniques. Three years after launch, more than 200 CHAMP investigators and co-investigators from all over the world met at the GeoForschungsZentrum in Potsdam to present and discuss the results derived from the  extensive data sets of the mission. The main outcome of this expert meeting is summarized in this volume. The book offers a comprehensive insight into the present status of the exploitation of CHAMP data for Earth system research and practical applications in geodesy, geophysics and meteorology.