Session 1: Gravimetry (terrestrial, shipborne, airborne) and gravity networks.

Chairs:Yoichi Fukuda (Japan), Leonid F. Vitushkin (BIPM, France), .
This Session solicits papers on the following topics:

  • classical and new methods and instrumentation for the absolute and relative terrestrial, shipboard, seaboard and airborne gravimetry and gradiometry,
  • investigations of the instrumentation for gravity measurements including the results of comparisons of absolute gravimeters,
  • combined techniques for gravity measurements (for example, absolute and superconducting gravimetry),
  • new types and technologies for gravity measurements (for example, atom interferometer gravimeters and gradiometers, airborne gravimetry on the zeppelins, etc.) including that for the planetary gravimetry,
  • results of the measurements of the gravity field on static and moving platforms,
  • formation of the gravity networks and their measurements, construction of gravity stations for precise gravity measurements,
  • standartization of the data of absolute gravity measurements and formation of data base of absolute measurements.

Session 2: Space-borne gravimetry: Present and Future.

Chairs:Roland Pail (Austria) and Pieter Visser (The Netherlands).
The successful launches of the satellite missions CHAMP (2000) and GRACE (2002) have led to a revolution in global Earth’s gravity field mapping by space-borne observation techniques, and have provided valuable contributions to many geoscientific fields of application, such as geodesy, hydrology, oceanography/altimetry, glaciology, and solid Earth physics. These two missions have proven new concepts and technologies, such as space-borne accelerometry and low-low Satellite-to-Satellite Tracking (SST), in combination with more conventional observation techniques, like GPS SST and Satellite Laser Ranging (SLR). CHAMP and GRACE have already produced consistent long- to medium-wavelength global gravity field models and its temporal changes, and have supported the preparation for the GOCE (2008) dedicated gravity field mission, which will further improve high-accuracy and high-resolution gravity field mapping employing for the first time in history the satellite gravity gradiometry (SGG) concept. For the realization of future gravity field missions, the limitations of the current mission concepts have to be studied, and innovative technologies, advanced sensor systems and mission concepts, such as formation flights, will have to be identified and investigated. Also alternative technologies such as ultra-precise clocks or atom interferometry, which are innovative in the field of gravity field research, might be considered for future mission concepts. Papers are solicited that address the topics of this session.

Session 3: Earth Observation by Satellite Altimetry and InSAR.

Chairs: Wolfgang Bosch (Germany), Masato Furuya (Japan), Roger Haagmans (ESA). Space-based Earth observations by radar altimetry and InSAR have evolved to operational remote sensing techniques with important interdisciplinary applications to many geosciences. This Session focuses on potential and already realized applications of these techniques, latest results and new developments with specific impact to geodetic science. Topics to be covered in this Sessiion include, but are not limited to

  • Procedures and results for precise mapping and monitoring of the Ocean and Earth surface, its short period variations (tides, hydrodynamics), secular evolution (sea level rise, uplift) or episodic deformation (earthquakes, tsunamis)
  • Improvements in quality and resolution of marine gravity or bathymetry by retracking or dedicated analysis of altimeter data.
  • Comparison between marine gravity and independent gravity field information (from land, ships, aircrafts, and satellites)
  • Methodology and algorithms for combining satellite-only and marine (terrestrial) gravity data for both, regional and global applications.
  • Procedures and results for estimating the sea surface topography as difference between mean sea level and geoid and its comparison with oceanographic estimates of the dynamic ocean topography.
  • New methodology and analysis techniques in InSAR data processing and algorithms, such as Persistent Scatterer Interferometry (PSI), short baseline stacking approach, newer phase unwrapping algorithms, etc.

Session 4: Geoid modeling and vertical datums.

Chairs: Ambrus Kenyeres (Hungary) and William Kearsley (Australia). Beyond its physical meaning the geoid is considered as vertical datum for leveling networks, represented by fundamental benchmark(s) at selected tide gauges. However the practical realization of the vertical datums, especially on continental scale was difficult and may led to inconsistencies. Additionally the limited geoid modeling accuracy hindered the realization of the global vertical datum. Since the availabilty of the satellite gravity mission's (CHAMP, GRACE) results our capability to accurately model the gravimetric geoid (from medium to long wavelengths) has largely increased, opening new opportunities for the vertical datum realization and applications. In several cases the new geoid models integrated with GNSS surveys are providing attractive alternative for height network definition and vertical surveying. The session focuses on the impact of the improved gravimetric geoid modeling and its use for vertical datum realization and solicits papers in the following topics:

  • problems and solutions related to global and regional vertical datum definitio,
  • combination of gravimetric geoid and GNSS surveying,
  • resolution of problems associated with terrain effects and downward continuation,
  • special problems associated with coastal regions.

Session 5: Regional gravity field modeling.

Chairs: Urs Marti (Switzerland) and Steve Kenyon (USA). This session will focus on the practical solution of various formulations of geodetic boundary-value problems to yield continental, regional and local geoid models. A main part will be the status reports of the projects for the accurate determination of the geoid on the continental scale. Contributions are welcomed that describe recent developments in theory, processing methods, downward continuation of satellite and airborne data, terrain modeling, software development and the combination of gravity data with GPS/leveling for an accurate local gravity field determination. Further topics are the comparison of methods and results, the interpretation of residuals as well as geoid applications to satellite altimetry, oceanography, and local geospatial height registration.

Session 6: Global gravity field modelling & EGM08.

Chairs: Nikos Pavlis (USA) and Jianliang Huang (Canada). Global gravity field modelling and determination has experienced a quantum leap during the last few years with the data collected by the USA/German satellite-to-satellite tracking mission GRACE. A successful deployment of the gradiometer mission GOCE by ESA will hopefully enable even further advances. The Shuttle Radar Topography Mission (SRTM) has improved tremendously our knowledge of the topography for about 80 percent of the Earth’s land surface. The continuous refinement of data processing algorithms (e.g., re-tracking) has also enabled an unprecedented mapping of the marine gravity field from satellite altimetry. These advances from space have been paralleled by continuous advances from airborne and land-based gravimetric data collections that take place much closer to the Earth’s surface. This unprecedented collection of complementary data offers geodesists unique opportunities and great challenges for highly accurate modelling of the gravity field, on a global scale and at very high-resolution. Several geodetic teams world-wide have been pursuing this challenging task both from the theoretical and from the numerical perspectives. The National Geospatial-Intelligence Agency of the USA has developed a new Earth Gravitational Model (EGM08) intended to replace the benchmark EGM96 model. The new model, which extends to degree 2160, performs in some cases equally well as (or better than) detailed gravimetric products, thus providing a new paradigm for gravimetric applications. We solicit oral and poster presentations focusing on the various (theoretical and numerical) aspects of global gravity field determination, the presentation of results from new models, from their evaluations, and from their inter-comparisons.

Session 7: Temporal gravity changes and geodynamics.

Chairs:Nico Sneeuw (Germany) and Juergen Kusche (Germany).
The session "Temporal Gravity Changes and Geodynamics" deals with the time variable gravity field of the Earth at all temporal and spatial scales. Papers are solicited on a variety of related topics, ranging from observation, methodological aspects and modeling of time-variable gravity to mass transport monitoring and applications in related disciplines. The session focuses in particular on the interactions with solid Earth physics and with atmospheric, hydrological, ice and ocean sciences.

Session 8: Earth observation and the Global Geodetic Observing System (GGOS).

Chairs:Richard Gross (USA) and Hans-Peter Plag (USA).
Measurements of the Earth’s rotation, shape, and gravity provided by global geodetic observing systems show that they change on a wide range of time scales reflecting the wide range of processes affecting them, from external tidal forces to surficial processes involving the atmosphere, oceans, and hydrosphere to internal processes acting both at the core-mantle boundary as well as within the solid Earth itself. Measurements taken by global geodetic observing systems can therefore be used to gain greater understanding of a wide variety of dynamic Earth processes, from tracking water in its various phases as it cycles through the atmosphere, oceans, and land, to crustal deformation associated with tectonic motions and glacial isostatic adjustment, to torsional oscillations of the core. This session will be a forum for discussing the present status and future evolution of global geodetic observing systems and their use to investigate dynamic Earth processes.

Session 9: Geodetic monitoring of natural hazards and a Changing Environment.

Chairs:Alexander Braun (Canada) and Rene Forsberg (Denmark).


With the ever increasing spatio-temporal resolution and improved accuracy of geodetic sensors, new target areas can be approached and new contributions to neighboring disciplines can be achieved with geodetic monitoring. This session invites contributions from studies which employ modern geodetic sensors to monitor and observe natural hazards and the Earth' changing environment on multiple-scales. The geodetic sensors used may include GNSS, satellites (altimetry, SAR, gravimetric), spaceborne and airborne Lidar, gravimetry, tide gauges and buoys, and surveying based on and/air/ship-borne platforms. Primary target areas include natural hazards due to earthquake cycles, volcanos, subsidence and deformation of the Earth' surface, sea level change, Arctic/Antarctic change, sea ice dynamics, melting of glaciers and ice sheets, permafrost change and flooding. Secondary targets involve changes in the Earth' environmental systems; vegetation, geomorphology, urban environments, surface water, avalanches and snow cover, rivers and lakes. It should be emphasized that this session will focus on integrated studies covering both geodetic sensors and target systems rather than focusing on improvements of sensors or numerical modelling of systems alone.