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The Global Geodetic Observing System Workshop 2006

Towards a Consistent Geodetic Foundation for Earth Observations

October 8-9, 2006
Munich, Germany
Last edited 29 October 2006

GGOS and its role in Earth Observation

The Global Geodetic Observing System (GGOS) of the International Association of Geodesy (IAG) has been organized to coordinate the geodetic support for the Earth sciences. GGOS will work with the IAG Services to provide the geodetic infrastructure necessary to support the monitoring of the Earth system and global change research. It will integrate the three pillars of geodesy, that is geometry and kinematics, Earth orientation and rotation, and gravity field and dynamics, in order to maximize the benefit for the scientific community and society in general.

This workshop was organized to help facilitate the communication between the scientific user community and those who will provide the geodetic products. The workshop helped to establish a clear set of well justified and well understood requirements that address user needs and at the same time be realizable. It provide a forum where related issues were discussed and tradeoffs were concluded.

It is anticipated such workshops will be regularly scheduled events to ensure that communication is two-way and that GGOS is responsive to the changing needs of the scientific community. The next GGOS Workshop in line with this objective will take place in November 2007 (see the meeting page for more information).

Workshop Objectives

The overall goal of the GGOS Workshop 2006 was to further develop the scientific rationale for GGOS as a consistent geodetic foundation for Earth observations. Geodesy provides observations of a unique set of observables related to the mass transport in and the dynamics of the Earth system. With the geodetic reference frames, geodesy also provides the metrological basis for all Earth observation. The increasing demand for comprehensive Earth observation as expressed in the recent developments brought about by the Earth Observation Summits (EOS) and the ensuing Group of Earth Observation (GEO), as well as the Integrated Global Observing Strategy Partnership (IGOS-P) constitutes an important boundary condition for the development of GGOS. It emphasizes the need to integrate the geodetic observing system into the broader context of Earth observations and to strive for increasing accuracy, resolution, consistency, long-term stability, and accessibility of the geodetic observations and derived products. Many scientific projects and programs make use of Earth observations, not least geodetic ones. International programs, in particular the United Nation's Agencies, increasingly depend on Earth observations for successfully meeting their missions. The Workshop addressed the global context of Earth observation in its relevance for GGOS and the IAG Services.

Geodetic observations are indispensable for a better understanding of crucial Earth system processes related to the nine societal benefit areas identified by EOS, including climate, weather, disasters, and the global water cycle. They are also a key to answering many of the open scientific questions related to the dynamics of the solid Earth and its fluid envelop. By reviewing the scientific and societal requirements for information related to mass transport and Earth system dynamics, the Workshop aimed at providing a comprehensive picture of the present and future scientific challenges for GGOS. In an assessment of the current geodetic concepts, observations and products, an attempt was made to identify the mismatches between the scientific challenges on the one side and the current capabilities on the other side. The major achievement of the Workshop is progress towards a scientifc roadmap that resolves these mismatches and ensures the geodetic contribution to Earth observations as needed by science and society.

Output of the Workshop

The main output of the Workshop is a set of position papers that, as far as possible, have been agreed upon by the Workshop participants. These papers give scientific directions for the future development of GGOS. They contribute to the scientific basis for the GGOS implementation plan as well as GGOS contributions to GEO, IGOS-P, and other relevant organizations and projects. The position papers are accessible here both through specific links and the Detailed Programme. It is intended to publish the papers in either a special issue of a relevant journal or in another appropriate form.

GGOS has initiated a strategy process, shortly denoted as GGOS2020, which is currently developing the strategy for the future GGOS based on a well defined set of scientific and non-scientific user requirements. The GGOS2020 Writing Team includes the GGOS Science Panel members, the GGOS Executive Committee, as well as a number of additional scientists and GGOS contributors. A draft strategy report was made available to the Workshop participants prior to the Workshop. The discussions at the Workshop will impact the further development of the strategy document, both through the position papers and the outcome of the discussions, as summarized by the rapporteurs.

Venue, Time and Context

The Workshop took place at the Technical University Munich, Munich, Germany. The Technical University is located at the city center of Munich, near the famous three Pinakotheks (art galleries).

The workshop took place on
Sunday, 08.10.2006 10:00 - 17:00 and
Monday, 09.10.2006 09:00 - 12:00.

Participants of the GGOS 2006 Workshop.

From October 9-13, 2006, several geodesy conferences were held in Munich:

In co-locating the GGOS Workshop with these meetings, GGOS made use of an opportunity, which brings a large number of geodetic experts to Munich.

Workshop Program

The workshop program was organized into five sessions. Four of the sessions were organized around one or two position papers each, while the last session was a summary and discussion session. The sessions were:

  1. Session 1: Status and Future of GGOS: This session gave an overview of the GGOS2020 draft report. The report was made available to all Workshop participants, who were strongly encouraged to review the draft report prior to the Workshop.
    Session chair: Ruth Neilan
    Rapporteur: R. Wonnacott
    Position paper:
    • M. Rothacher et al.: A long-term strategy for GGOS: Serving the needs of a global society on a dynamic planet.
  2. Session 2: The Science of Earth System Dynamics: The goal of this session was to review open scientific problems associated with or benefiting from information about mass transport in and dynamics of the Earth system. Moreover, this session addressed to what extent knowledge on mass transport and dynamics is required for the GEO and IGOS-P objectives.
    Session chair: Susanna Zerbini
    Rapporteur:H. Schuh
    Position papers:
    • R. Gross: Mass transport and dynamics in the Earth system: the unsolved scientific questions and observational requirements
    • H.-P. Plag, A. Cazenave, and D. Sahagian: What do we need to know about mass transport and Earth dynamics for the nine benefit areas of GEO?
  3. Session 3: Targeting the 0.1 ppb accuracy level for GGOS data and products: What are the limiting inconsistencies? This session analyzed the current geodetic concepts, observations, and products of the three pillars of geodesy in order to identify possible inconsistencies and potential problems that might lead to a mismatch between the quality of the geodetic products and the scientific and societal user requirements. A general requirement addressed here was the accuracy target of GGOS at the level of 0.1 ppb.
    Session chair:Michael Pearlman
    Rapporteur: E. Pavlis
    Position papers:
    • V. Dehant and H. Drewes: Inconsistencies in geodetic concepts, models and analyses at the 0.1 ppb level
    • S. Kenyon and C. Ma: Inconsistencies in IAG data, products and services at the 0.1 ppb level
  4. Session 4: Towards a Combined Analysis of Geodetic Observations Across the Three Pillars of Geodesy: It was expected that a major progress toward the goals of GGOS would originate from a consistent and combined analysis of observations of the changes in the Earth's geometry, gravity field and rotation. Therefore, this session focussed on the internal integration of geodesy's three pillars as a major aspect of the scientific roadmap for GGOS.
    Session chair: Chris Rizos
    Rapporteur: R. Haagmans
    Position papers:
    • R. Rummel: Bridging the conventional and observational gap between geometry and gravity
    • Z. Altamimi and D. Coulot: How can combination help to achieve consistency at the 0.1 ppb level?
  5. Session 5: Towards a strategy for the future GGOS: In this closing session, the Rapporteurs summarized the main conclusions of the position papers and discussions with particular emphasis on their relevance for the GGOS strategy. Room was given for a plenary discussion of the draft strategy document.
    Session chairs: Markus Rothacher, Ruth Neilan, Hans-Peter Plag
The detailed Workshop programme including times is available here.


The Workshop program was organized by the GGOS Executive Committee, which acted as the Program Committee for the Workshop.

The workshop took place at the Technical University Munich (see http://www.tu-muenchen.de), and the practical organization was supported by the German GOCE Project Bureau at TU Munich for the coordination of research activities on the GOCE gravity field satellite mission.

Local Organizing Committee:
Jakob Flury
Reiner Rummel
Katrin Gundrum

Head of the Local Organizing Committee:
Dr.-Ing. Jakob Flury
Technical University Munich
Institute for Astronomical and Physical Geodesy
Arcisstr. 21
D-80290 Munich
email flury@bv.tum.de
Tel ++49-89-28923179
Fax ++49-89-28923178

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