Global Gravity Field And Its Temporal Variations

In July 1995 the XXI General Assembly of the International Union of Geodesy and Geophysics was held in Boulder, Colorado. At this meeting the International Association of Geodesy (lAG) organized a number of symposia to discuss scientific developments and future directions in a number of areas. One of these symposia was G3, Global Gravity Field and Its Temporal Variations. This symposium consisted of four invited and 36 contributed papers. The contributed papers were given as oral or poster presentations. This proceedings volume represents the written contributions of the four invited papers (appearing as the first four papers in the volume) and 19 additional papers. The authors were asked to limit the length of their paper to approximately ten pages, which, in some cases, did limit what an author wanted to say. The papers in this volume have been placed in the same order as they were presented at the ruGG meeting. A key theme of the symposium is given in the paper by Nerem, Klosko, and Pavlis where they discuss applications of gravity field information in geodesy and oceanography. The significant achievements in determining the gravity field in the ocean areas from satellite altimeter data is discussed by Sandwell, Yale, McAdoo, and Smith. A review of time changes of the Earth's gravity field from terrestrial measurements is given by Lambert et aI. , and from satellite perturbation techniques by Eanes and Bettadpur. A description of new geopotential models is given in the paper by Tapley et al.

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.

This book provides a sound theoretical basis for the the different gravity field recovery methods and the numerics of satellite-to-satellite tracking data. It represents lectures given at the ‘Wilhelm and Else Heraeus Autumn School’ in Bad Honnef, Germany, October 4-9, 2015. The emphasis of the school was on providing a sound theoretical basis for the different gravity field recovery methods and the numerics of data analysis. The approaches covered here are the variational equations (classical approach), the acceleration approach and the energy balance approach, all of which are used for global gravity field recovery on the basis of satellite observations. The theory of parameter estimation in satellite gravimetry and concepts for orbit determination are also included. The book guides readers through a broad range of topics in satellite gravimetry, supplemented by the necessary theoretical background and numerical examples. While it provides a comprehensive overview for those readers who are already familiar with satellite gravity data processing, it also offers an essential reference guide for graduate and undergraduate students interested in this field.

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.

This book provides a collection of selected articles that have been submitted to the Earth Observation and Global Changes (EOGC2011) Conference. All articles have been carefully reviewed by an international board of top-level experts. The book covers a wide variety of topics including Physical Geodesy, Photogrammetry & Remote Sensing, High-Resolution and Fast-Revisiting Remote Sensing Satellite Systems, Global Change & Change Detection, Spatial Modelling, GIS & Geovisualization. The articles document concrete results of current studies related to Earth Sciences. The book is intended for researchers and experts working in the area of Spatial Data Analysis, Environmental Monitoring/Analysis, Global Change Monitoring and related fields.

Our planet is currently experiencing substantial changes due to natural phen- ena and direct or indirect human interactions. Observations from space are the only means to monitor and quantify these changes on a global and long-term p- spective. Continuous time series of a large set of Earth system parameters are needed in order to better understand the processes causing these changes, as well as their interactions. This knowledge is needed to build comprehensive Earth s- tem models used for analysis and prediction of the changing Earth. Geodesy and geophysics contribute to the understanding of system Earth through the observation of global parameter sets in space and time, such as tectonic motion, Earth surface deformation, sea level changes and gravity, magnetic and atmospheric elds. In the framework of the German geoscience research and development p- gramme GEOTECHNOLOGIEN, research projects related to the theme “Observing the Earth System from Space” have been funded within two consecutive phases since 2002, both covering 3 years. The projects address data analysis and model development using the satellite missions CHAMP, GRACE, GOCE and comp- mentary ground or airborne observations. The results of the rst phase projects have been published in the Springer book, titled “Observation of the Earth System from Space”, edited by Flury, Rummel, Reigber, Rothacher, Boedecker and Schreiber in 2006. The present book, titled “System Earth via Geodetic-Geophysical Space Techniques” summarizes in 40 scienti c papers the results of eight coordinated research projects funded in the second phase of this programme (2005–2008).