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Our Changing Climate
  The Important Role of Earth observations  
  Future Challenges  


CEOS is the Committee on Earth Observation Satellites, created in 1984 in response to a recommendation from a Panel of Experts on Remote Sensing from Space, under the aegis of the G-7 Economic Summit of Industrialised Nations Working Group on Growth, Technology and Employment.

CEOS was established to provide coordination of the Earth observations being provided by satellite missions, recognising that no single programme, agency, or nation can hope to satisfy all of the observational requirements which are necessary for improved understanding of the Earth System. Since its establishment, CEOS has provided a broad framework for international coordination on spaceborne Earth observation missions.

What does CEOS Contribute?
CEOS strives to facilitate the necessary harmonisation and achieve maximum cost-effectiveness for the overall set of space-based observation programmes of member countries and agencies.

CEOS has established three primary objectives in pursuing this goal:

— to optimise benefits of spaceborne Earth observations through cooperation of its members in mission planning and in development of compatible data products, formats, services, applications and policies;

— to serve as a focal point for international coordination of space-related Earth observation activities;

— to exchange policy and technical information to encourage complementarity and compatibility of observation and data exchange systems.

The work of CEOS spans the full range of activities required for proper international coordination of Earth observation programmes and maximum utilisation of their data. It ranges from the development of detailed technical standards for data product exchange, through to the establishment of high level inter-agency agreements on common data principles for different application areas, such as global climate change and environmental monitoring.


CEOS website

Who Participates in CEOS?
CEOS membership comprises most of the world’s civil agencies responsible for Earth observation satellite programmes – 29 Members in 2010. CEOS also has 20 Associates, comprising:

— international or national governmental organisations that are developing Earth observing satellite programmes or significant supporting ground facility programmes;

— other satellite coordination groups and scientific or governmental bodies that are international in nature and currently have a significant programmatic activity that supports CEOS objectives.

— The full list of Members and Associates is shown in the tables below.

How Does CEOS Operate?
CEOS Principals meet annually in a Plenary session to determine policy, review progress on the projects and activities being undertaken, and set the agenda of activities for the upcoming year. The Chair of CEOS rotates at the annual Plenary.

The work of CEOS is conducted within its various working groups and the Strategic Implementation Team (SIT).

Coordination throughout the year is maintained
through a permanent Secretariat maintained by
the European Space Agency (ESA) jointly with the
European Organisation for the Exploitation of
Meteorological Satellites (EUMETSAT), the
National Aeronautics and Space Administration
(NASA) jointly with the National Oceanic and
Atmospheric Administration (NOAA) of the USA,
and the Ministry of Education, Culture, Sports,
Science and Technology (MEXT) jointly with the
Japan Aerospace Exploration Agency (JAXA).

Earth observation heads of 29 space agencies from around the globe meet annually at the CEOS Plenary.
CEOS Activities and Achievements
The establishment of the Group on Earth
Observations (GEO) via a series of three
ministerial-level summits from 2003 to 2005
provided a new focus and impetus for CEOS
efforts. GEO includes 80 member countries, the
European Commission, and 56 participating
organisations – including CEOS – working
together to establish a Global Earth Observation
System of Systems over the next 10 years.

The GCOS plans are recognised as the climate
component of GEOSS and they are addressed in
this document in both contexts.

The GEO vision for GEOSS is to realise a future in
which decisions and actions for the benefit of
humankind are informed via coordinated,
comprehensive and sustained Earth observations
and information. The 20+ years invested by CEOS
agencies towards these objectives has resulted in
recognition of CEOS as the primary worldwide
forum for coordination of space-based Earth
observations. As such, CEOS is tasked to lead
coordination of the space observations required
by the GEOSS.

The main mechanisms which CEOS employs to
implement this role are:

— the CEOS Virtual Constellations for GEOSS;

— the CEOS Working Groups;

— the CEOS Implementation Plan and teams to

address the various tasks therein.
Each of these is discussed in turn below.

CEOS Virtual Constellations for GEOSS
The CEOS Virtual Constellations for GEOSS provide a new mechanism for better coordination of Earth observing satellite programmes across borders, allowing valuable contributions from a wide range of parties to build and sustain truly global observing systems in support of one or more key information needs of society. The Virtual Constellations concept involves multiple satellites working in harmony as part of the GEOSS to augment coverage, enhance system compatibility and increase data availability. Such an arrangement encourages international cooperation among space agencies while stimulating them to develop a coordinated response to space-based observation needs. It also fosters improved data management and distribution worldwide.

Four prototype virtual constellations are currently in progress by CEOS space agencies, in consultation with their respective user communities – each with a major outcome in support of climate and other applications:

— The Precipitation Constellation, which aims to strengthen international cooperation of space-based observations of precipitation, including realisation of the Global Precipitation Measurement (GPM) mission;

— The Land Surface Imaging Constellation, designed to ensure continuity and compatibility of planned land remote sensing systems;

— The Atmospheric Composition Constellation, which will address many of the climate community’s needs for atmospheric observations;

— The Ocean Surface Topography Constellation, designed to ensure continuity of sea level measurement in accordance with GCOS requirements.

Each of these is designed to make key observations for the GEOSS and maintain continuity of observations, identifying and addressing potential gaps and overlaps. Part of the process is to clearly identify organisational responsibilities for ensuring the necessary continuity. Further details of the CEOS Constellations are provided in the Case Studies in Part II of this document.

The Strategic Implementation Team (SIT) of CEOS is where heads of space agencies or Earth observation programmes meet to make the decisions required to harmonise their observing programme plans. SIT plays a central role in coordination of existing and future missions of CEOS agencies to support GEO in its realisation of the GEOSS space segment. The Chair of SIT has a two year term, with an already-nominated deputy ready to take over. This provides a level of continuity which has resulted in the Chair of SIT being appointed as the primary interface between CEOS and GEO.

SIT has never had a formal membership. Meetings are open to any CEOS agency which is willing and ready to contribute to one or more of the activities being discussed by SIT, such as the Virtual Constellations projects or particular GEOSS space segment implementation tasks.

CEOS newsletter
CEOS Working Groups
CEOS also uses three Working Groups to implement its activities:

— Working Group on Calibration and Validation (WGCV): with activities on calibration and validation of Earth observations for the benefit of CEOS members and the international user community;

— Working Group on Information Systems and Services (WGISS): focused on interoperability and interconnectivity of information systems and services related to the capture, archiving and exploitation of EO data;

— Working Group on Education, Training and Capacity Building (WGEDU): facilitating activities that substantially enhance international education and training in Earth System Science as well as the observation techniques, data analysis and interpretation required for its use and application to societal needs.

More information is provided in Annex A.

The CEOS Implementation Plan
The first version of the CEOS Implementation Plan, prepared by the Strategic Implementation Team, was published and endorsed in 2007. It is the mechanism by which CEOS now prioritises, manages and monitors its various tasks in support of the development of the space-based observations for the GEOSS, of which the Global Climate Observing System is a significant part. The CEOS Implementation Plan represents a move to a business-like and target-oriented agenda for CEOS as it responds to its responsibilities in support of the GEOSS.

As part of the adoption of the Implementation Plan in 2007, the 29 member space agencies of CEOS agreed to establish expert teams for each of the 9 ‘Societal Benefit Areas’ of the GEOSS, each with the responsibility of progressing and reporting on activities in support of the various GEOSS targets. Oversight of the entire activity is undertaken by the Chair of the CEOS Strategic Implementation Team (SIT), with support from the CEOS Executive Officer (CEO). In 2008, the CEO and SIT Chair have been working closely with the GEO Secretariat in order to prioritise the many actions required for CEOS in support of the GEOSS space segment.

The CEOS IP will be updated annually to demonstrate how well the coordination processes are working to achieve the required outcomes.

More Information
Further information on the structure, activities, and achievements of CEOS is provided in Annex A of this document.

Further Information
Earth Observation Handbook:
CEOS Newsletter:
CEOS Response to GCOS IP:




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