An improved understanding of the Earth System its weather, climate, oceans, land, geology, natural resources, ecosystems, and natural and human-induced hazards is essential if we are to better predict, adapt, and mitigate the expected global changes and their impacts on human civilization. Earth observation data and derived information are essential inputs in the development of this understanding. Earth observations provide the evidence necessary for informed decision-making supporting the science which underpins strategies for global environmental decision-making and for monitoring our progress on all geographical scales as we explore new development paths aimed at sustainable management of the planet.
There are estimated to be more than 100 Earth observation satellite missions currently operating, sending environmental information such as cloud cover, sea surface winds, and volcanic activity to ground stations and space centers around the world. Earth observing systems help to provide data in support of a wide range of information needs, including parameters which are central to: improved understanding of Earth system processes; improved predictions, especially on a regional scale; evidence vital for governments when deciding whether to fund mitigation measures in response to climate change; monitoring and compliance; and management and mitigation. The beneficiaries of Earth observations are a broad range of users including: national, regional and local decision-makers; organizations responsible for the implementation of international Conventions and treaties; business, industry, and service sectors; scientists, researchers, and educators; and ultimately, every inhabitant of planet Earth.
Earth observation satellites can be owned and operated by governments, international organizations, commercial companies, research and academic institutions, and others. Because of the varied ownership, many of these systems operate independently, exchanging little or no information with other organizations. Producing better information on the global environment has become a worldwide priority, and international partnerships are essential to achieving this goal because no country can monitor the entire Earth by itself. Understanding a planet as complex as Earth clearly requires a global effort. In 1984, as scientists were beginning to frame the critical questions that needed to be answered, several space-faring nations created the Committee on Earth Observation Satellites, CEOS, to coordinate internationally all civil space-borne missions designed to observe and study our planet.
Bringing space-based sensors, ground-based data analysis systems, and skilled experts together requires a well-coordinated international effort and a strong commitment from space agencies. CEOS was established in 1984 at the request of the Economic Summit of Industrialised Nations Working Group (G7) on Growth, Technology, and Employment, as the international forum for space agencies in Earth observation (EO). This group recognized the multidisciplinary nature of satellite EO and the value of coordination across all proposed missions.
CEOS is dedicated to international collaboration among space systems and EO missions. Participating agencies strive to address critical scientific questions and to develop national satellite programs with common standards and systems that can provide data to the international community while not unnecessarily overlapping satellite missions of other agencies. The purpose, mission, and requirements of space systems, however, remain the responsibility of individual space agencies.
CEOS has three primary objectives:
Governmental organizations that are international or national in nature and are responsible for a civil space-borne Earth observation program currently operating or in development are eligible for membership in CEOS. In addition, CEOS accepts associate membership for Governmental organizations that are international or national in nature and currently have a civil space-segment activity in planning phases or a significant ground-segment activity that supports CEOS objectives as well as other existing satellite coordination groups and scientific or governmental bodies that are international in nature and currently have a significant programmatic activity that supports CEOS objectives. CEOS currently has 28 Member Agencies and 20 Associate Agencies. This chart depicts the CEOS elements.
CEOS Role for the Global Earth Observation System of Systems (GEOSS
The intergovernmental Group on Earth Observations, GEO, was established by a series of three ministerial-level summits. GEO includes more than 75 member countries (http://earthobservations.org), the European Commission, and more than 50 participating organizations including CEOS working together to establish a Global Earth Observation System of Systems (GEOSS). The GEO vision for GEOSS is to realize a future wherein decisions and actions for the benefit of humankind are informed via coordinated, comprehensive, and sustained Earth observations and information. GEOSS will build on and add value to existing Earth-observation systems by coordinating their efforts, addressing critical gaps, supporting their interoperability, sharing information, reaching a common understanding of user requirements, and improving delivery of information to users.
CEOS provides active and engaged support to GEO, especially the space component of GEOSS, where CEOS is able to play a unique and important role. The 20+ years invested by CEOS agencies towards these objectives has resulted in recognition of CEOS as the primary forum worldwide for coordination of space-based Earth observations. In 2007, CEOS developed an Implementation Plan for Space-based Observations for the GEOSS, which identifies the targets and actions required for delivery of the space segment of GEOSS focused exclusively on the space segment aspects and on the efforts of space agencies to implement it. CEOS Member space agencies have endorsed the decision that the execution of this plan becomes the primary activity of CEOS as a coordination body and of its subsidiary groups.
The CEOS Implementation Plan (CEOS IP) adopts the same target timescales as the underlying GEOSS Plan (2 years, 6 years, and 10 years) and priorities have been assigned to a large number of actions designed to achieve the target outcomes for the GEOSS.
There are three main implementation mechanisms (and resource pools) available to CEOS to undertake the work required on individual actions in support of GEOSS space segment targets: (1) the Strategic Implementation Team (SIT) and the CEOS Secretariat; (2) the CEOS Working Groups; and (3) the CEOS Virtual Constellations. These groups are described next.
CEOS Strategic Implementation Team (SIT)
The CEOS Strategic Implementation Team (SIT) was created in 1996 to advance the involvement of CEOS in the development of the Integrated Global Observing System (IGOS). The SIT is comprised of CEOS Member Principals and some Associates with the authority to commit agency support to initiatives as they unfold. With the integration of IGOS Themes into GEO, the SIT now plays a central role in coordination of existing and future missions of CEOS agencies, particularly to support GEO in its realization of the space segment of GEOSS. The SITs objective is to define, characterize, and develop the vision for CEOS participation in GEO and in particular, to strengthen the CEOS linkages to GEO and GEOSS. The SIT is currently engaged in objectively defining and prioritizing a series of actionable actions and demonstrated results that will support corresponding GEO Societal Benefit Area (SBA) Tasks. For each of the GEO Tasks that CEOS contributes to, key CEOS actions have been identified with a direct traceability established. The SIT places strong emphasis on progressing GEO Tasks and has achieved commitments from CEOS agencies to conduct the assigned Tasks.
This group provides most of the coordination between plenary sessions and is maintained jointly by the European Space Agency (ESA), the European Organization for the Exploitation of Meteorological Satellites (EUMETSAT), the National Aeronautics and Space Administration (NASA), the National Oceanic and Atmospheric Administration (NOAA) of the United States, the Ministry of Education, Culture, Sports, Science and Technology (MEXT) and the Japan Aerospace Exploration Agency (JAXA).
CEOS Working Groups
Working Group on Calibration and Validation (WGCV)
The goals of the WGCV are to enhance coordination and complementarity, to promote international cooperation, and to focus activities in the calibration and validation of Earth observations for the benefit of CEOS Members and the international user community. WGCV addresses issues relating to sensor system calibration/validation as well as validation of geophysical parameter/derived products. A major emphasis of these activities is to enable reliable comparison and synergistic use of information across the global gamut of Earth observing systems in support of GEO and GEOSS goals and objectives. The subgroups of WGCV are as follows: Terrain Mapping; Microwave Sensors; Synthetic Aperture Radar; Infrared/Visible Optical Sensors; Land Product Validation; and Atmospheric Composition.
Working Group on Information Systems and Services (WGISS)
The major CEOS goal is to coordinate the development of satellite Earth Observation missions. The CEOS WGISS provides the means of achieving the CEOS primary coordination objectives by providing a range of data and information services better attuned to the needs of users than could be delivered by provider members and associates acting independently. Through WGISS, the policies of coordination and cooperation between the programs of the Members and Associates can be realized.
Working Group on Education, Training, and Capacity Building (WGEdu)
The key task of the CEOS Working Group on Education, Training, and Capacity Building (WGEdu) is to coordinate existing and planned education and training activities of its Members in Earth observation techniques, data analysis and interpretation, use of derived standard products and services, and Earth observation applications. Emphasis also is placed upon the development and provision of education and training resources that maximize the societal benefits of Earth observation data, products, and services, particularly for developing countries.
CEOS Virtual Constellations
In support of GEO objectives and as a space component of GEOSS, CEOS has developed the concept of virtual, space-based Constellations. A CEOS Virtual Constellation is a set of space and ground segment capabilities operating together in a coordinated manner, in effect a virtual system that overlaps in coverage in order to meet a combined and common set of Earth Observation requirements. The individual satellites and ground segments can belong to a single or to multiple owners.
The Constellation concept builds upon or serves to refocus already existing projects and activities. The Constellations effort provides a unique forum to achieve political visibility and increase mutual benefit among space and other environmental agencies in support of cross-cutting GEO Tasks and Targets. In particular, they offer opportunities to share experience in the development of algorithms; standardize data products and formats; exchange information regarding the calibration and validation of measurements; facilitate timely exchange of and access to data products from existing and planned missions; and facilitate planning of new missions ranging from coordinating orbits to optimizing observational coverage to sharing implementation of mission components. The interim goal of a Constellation is to demonstrate the value of a collaborative partnership in addressing a key observational gap; the end goal is to sustain the routine collection of critical observations. Implementation of Constellation activities is ultimately dependent on the coordination of formal agreements among participating agencies.
Four initial, or pilot, Constellations currently exist: Land Surface Imaging; Ocean Surface Topography; Atmospheric Composition; and Precipitation. Two new Constellations were proposed in 2008 and are currently under development for full implementation: Ocean Colour Radiometry and Ocean Surface Vector Wind. Each Constellation study has a lead or leads from space agencies with a heritage of operations in the relevant EO domain, and a team of participants from other space agencies willing to contribute to implementation coordination through CEOS.
The Constellations might be considered to be a cross-cutting activity within CEOS. Some studies do map directly onto specific GEOSS space segment requirements (e.g., the Precipitation Constellation directly serves the GEOSS targets of 3-hourly global precipitation measurements and for implementation of the Global Precipitation Model [GPM] and other supporting missions). The outputs of the other studies span the targets of several Societal Benefit Areas (SBAs) including Climate in all cases and the provision of observations for Essential Climate Variables (ECVs) and are equally important in providing resources and attention to the issue of continuity of space-based observations for key measurements of ocean, atmosphere, and land.
Major Recent CEOS Achievements
In 2008, CEOS Agencies allocated a large number of resources to secure the successful completion of a number of significant activities. As a result of these collective efforts, more than 30 new datasets have been generated, most of these publicly accessible. The following representative examples illustrate some of the 2008 CEOS accomplishments, specifically in support of the GEO:
Development and distribution of the CEOS 2008 Earth Observation Handbook, a special issue which provides a comprehensive overview of efforts to address Climate Change and a major update on space-based Earth Observation missions.
A large share of 2008 CEOS priority actions addressed all aspects of climate-related observation of the atmosphere, ocean, and land. These have included improvement of data calibration and validation, reprocessing of past datasets, and improving availability of data and products to all countries. For example, Essential Climate Variables (ECVs) for the Arctic and Antarctic have been generated in real-time from NOAAs Advanced Very High Resolution Radiometer (AVHRR) sensor data to support the International Polar Year and to provide a long-term historical dataset of polar climate change ranging from 1981 to the present. Products include surface temperature, snow and ice extent, and clouds and winds.
In support of GEO objectives, CEOS has also successfully completed a number of key activities in connection with the Virtual Constellations concept described earlier. Good progress has been achieved in the initial four constellations focused on Atmospheric Composition, Land Surface Imaging, Ocean Surface Topography, and Precipitation. Two new additional Virtual Constellations are proceeding with implementation: Ocean Colour Radiometry and Ocean Surface Vector Winds. The Ocean Colour Radiometry Constellation will provide scientific data products related to marine ecosystems and ocean biogeochemistry for near-surface global ocean and coastal waters. The Ocean Surface Vector Wind Constellation will collect observations of ocean surface vector winds over the global ice-free ocean that will be used for operational analyses and forecasts, as well as retrospective research.
Major On-Going CEOS Activities
Among its priorities for 2009 and following the declarations from the last G8 in Toyako (Japan), in July 2008, CEOS Agencies will conduct focused activities in two main areas: (1) deforestation and forest degradation, relating to Reducing Emissions from Deforestation and Degradation (REDD) and monitoring of other carbon trading and financial instruments; and (2) closely associated measurements relevant to the reduction of greenhouse gas emission and to better understand climate change processes and modeling.
CEOS and Future Earth Observation
CEOS agencies are operating or planning around 240 satellites with an Earth observation mission over the next 15 years. These satellites will carry more than 385 different instruments. The sustained investment by space agencies will ensure the provision of information of unique value in both public and commercial spheres, derived from the measurements of a diverse range of geophysical parameters and phenomena. For more information, please visit the CEOS website www.ceos.org.
The 2009 CEOS Chair is Dr. Darasri Dowreang and the article has been provided to SatMagazine, courtesy of the CEOS Secretariat. Additionally, Dr. Dowreang is the Deputy Director, Geo-Informatics and Space Technology Development Agency of Thailand.