The Global Geodetic Observing System Workshop 2006
Towards a Consistent Geodetic Foundation for Earth Observations
October 8-9, 2006
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).
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
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
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
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
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.
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:
The detailed Workshop programme including times is available
- 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
- M. Rothacher et al.: A long-term strategy for GGOS: Serving the needs of a global
society on a dynamic planet.
- 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
- 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?
- 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
- 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
- Session 4: Towards a Combined Analysis of Geodetic Observations Across
the Three Pillars of Geodesy: It was expected that a major progress
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
three pillars as a major aspect of the scientific roadmap for GGOS.
Session chair: Chris Rizos
Rapporteur: R. Haagmans
- 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?
- 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 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:
Head of the Local Organizing Committee:
Dr.-Ing. Jakob Flury
Technical University Munich
Institute for Astronomical and Physical Geodesy