Acta Astronautica Voi.24. pp. 83-88, 1991 0094-5765/91 $3.00 + 0,00 Printed in Great Britain Pergamon Press plc

COORDINATING EARTH OBSERVATIONS FROM SPACE: TOWARD A GLOBAL EARTH OBSERVING SYSTEM

D. Brent Smith,* Linda V. Moodie,**

and Betty A. Howard**

National Oceanic and Atmospheric Administration Washington, D.C.

Lisa R. Shaffer*** and

Peter Backlund**** SM Systems and Research Corporation

Washington, D.C.

Abstract Introduction

The paper develops the rationale for coordination of Earth observation missions among national and regional agencies to overcome resource limita- tions, avoid duplication of effort, and make a significant contribution to global change monitoring and assess- ment. A global Earth observing system must involve all agencies with program- matic and funding responsibility and must be responsive both to scientific inputs and user needs. The paper briefly examines the objectives, current activities, and the linkages among existing Earth observation coordination groups. It advocates the need for a more effective forum for developing consensus across the whole spectrum of Earth and environmental observations satellite missions and proposes the strengthening of the Committee on Earth Observations Satel- lites (CEOS), a coordination group created as a result of the Group of Seven Economic Summit's Panel of Experts on Remote Sensing from Space. CEOS should be restructured to include representation of international scien- tific and intergovernmental user or- ganizations and should develop formal linkages to other existing satellite coordination groups. A revitalized CEOS should focus on collaboration in the development and operation of research and operational missions, the sharing of data to assist in global change decision-making, and the con- struction of international data net- works to facilitate global change data management.

* Chief, International and Interagency Affairs Office, National Environmental Satellite Data and Information Service (NESDIS) ** NESDIS International Affairs Officer *** Senior Policy Analyst **** International Affairs Specialist

This paper is declared a work of the U.S. Government and is not subject to copyright protection in the United States.

Earth observations from space have been conducted on a routine basis since the launch of the TIROS weather satel- lite thirty years ago. Other U.S., as well as Soviet, French, Japanese, Indian and Chinese Earth observation satellites have followed, and the number of nations and agencies develop- ing such satellites and sensors con- tinues to expand. Important additional Earth observation missions will be in orbit in time for the 1992 International Space Year.

The Rationale for Collaboration

While Earth observation missions have been and continue to be developed and operated in response to national and regional requirements, it is increasingly obvious that no one nation has the financial resources to develop the full complement of sensors required to mount a broadscale Earth observation research effort or to maintain full operational environmental coverage. Such realization has fostered bilateral and multilateral cooperation in the development of specific missions: the UK, France and Canada have provided instrument contributions to NOAA's polar-orbiting environmental satel- lites, with additional future contributions expected from the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT); NASA and the French National Space Centre (CNES) are collaborating in the TOPEX/POSEIDON altimetry mission; the Search and Rescue Satellite (SARSAT) program is maintained by U.S., Canadian and French contributions, with these partners cooperating with the Soviet Union in the international COSPAS/SARSAT program; NASA and CNES are contributing sensors to the Japanese ADEOS platform; the Soviet Union will fly a NASA TOMS ozone instrument; and Brazil and China are planning development of the CBERS remote sensing satellite series.

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NASA, NOAA, the European Space Agency (ESA), EUMETSAT, and counterpart Japanese and Canadian agencies have joined together in discussions aimed at achieving cooperation in the develop- ment and operation of complementary polar platform and free-flyer satellite missions. This ongoing effort to fashion a global Earth observing system along the lines proposed in NASA's proposed Mission to Planet Earth also demonstrates the importance of working to avoid duplication of effort and achieve compatibility among sensors, thereby enhancing scientific return and addressing the needs of users for data comparability and common formats.

Global Change Monitoring and Assessment

The issue of global climate change confronts all nations and requires that all join together in monitoring our global environment and using the resulting information to better under- stand and more accurately measure and predict the impacts of such change. Space-based Earth observations are playing a major role in such global change monitoring and assessment. The NOAA polar-orbiters, Landsat, SPOT and other currently operating satellites are providing initial measurements to complement extensive ground-based observations. Additional satellites and polar platforms will be deployed during this decade with an expected exponential increase in the amount of Earth observation data.

Important international global change coordination efforts are being undertaken on a scientific level through the International Geosphere Biosphere Program (IGBP) of the Inter- national Council of Scientific Unions (ICSU) and the World Climate Research Program (WCRP) of the World Meteorolog- ical Organization (WMO). Among inter- governmental user organizations, the WMO convenes a satellite experts panel and stresses the importance of the space segment to its "Global Observing System." The Intergovernmental Oceano- graphic Commission (IOC) proposes establishment of a "Global Ocean Observing System." The Global Environ- ment Monitoring System (GEMS) of the United Nations Environment Programme (UNEP) is placing increased emphasis on space-based observations in developing the Global Resources Information Database (GRID). Both UNEP and WMO support the activities of the Inter- governmental Panel on Climate Change (IPCC), an important intergovernmental body that has actively focused on issues of human-induced global climate change and is preparing to report its findings to the Second World Climate

Conference convening in Geneva in late October 1990.

While international scientific groups and intergovernmental user organizations play a valuable role in setting requirements and in establish- ing the rationale for collective international action, it is evident that a global system of space-based Earth observations must necessarily comprise national and regional government entities with authority to readily implement decisions that are reached. Coordination on a truly global scale must therefore involve all national and regional agencies that have programmatic and funding responsibility for Earth observations programs.

Earth Observation Coordination Groups

It should not be necessary to create a new coordination mechanism among space-based Earth observations agencies as several such coordination groups already exist. Rather, it should be possible to restructure existing groups and the linkages among them to more effectively develop the infrastructure for a global system. Existing inter- national satellite coordination groups already provide an important forum for policy and technical discussions on development and operations efforts as well as international data sharing and data management. Strong working relationships are already in place among the counterpart agencies involved in such groups.

The following section briefly examines the objectives, current activities and linkages among four existing Earth observation coordination groups involving national and regional agencies: the Committee on Earth Observations Satellites (CEOS), the Earth Observation International Coordination working Group (EO-ICWG), the International Polar-Orbiting Meteorological Satellite Group (IPOMS), and the Coordination on Geostationary Meteorological Satellites (CGMS) group.

CEOS was established in September 1984 by the Panel of Experts on Remote Sensing from Space, one of several panels constituting the Group of Seven Economic Summit's Working Group on Technology, Growth and Employment. CEOS also subsumed the activities of two coordination groups created as a result of a May 1980 multilateral meeting in Ottawa of representatives of nations developing remote sensing satellites. These two groups were the Coordination of Land Observing Satellites (CLOS) group consisting of

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the United States, France, India and Japan, and the Coordination of Ocean Remote Sensing Satellites (CORSS) group, consisting of ESA and Japan.

Charter membership in CEOS was granted to national and regional governmental agencies responsible for a spaceborne Earth observations program currently operating or at least in Phase-B or equivalent of system devel- opment. Initial membership consisted of the Canada Centre for Remote Sensing, CNES, ESA, the Indian Space Research Organization, the Brazilian Space Institute (INPE), Japan, NASA and NOAA. The British National Space Centre, Italy and the Federal Republic of Germany were admitted as members in 1986 on the basis of their development of space Earth observation sensors. Australia and EUMETSAT were admitted as members in 1989.

CEOS encourages complementarity and compatibility among space-borne Earth observation systems through cooperation in mission planning and through devel- opment of compatible data products, services, and applications. The CEOS Plenary has met at least every two years and has received progress reports from and provided direction to its two working groups. Technical coordination is carried out through these two groups which meet up to three times a year -- the Working Group on Data, and the Sensor Calibration and Performance Validation Working Group. The CEOS working Group on Data, chaired by NOAA, has played an active role in standard- izing data formats worldwide, achieving an international interoperable catalog system, and identifying data sets to test a proposed international network for electronic data transmission. The Sensor Calibration and Performance Validation Working Group, chaired by ESA, has focused to date on calibration and validation activities associated with the European ERS-I mission.

The EO-ICWG was formed in 1986 and includes the Earth observation offices of the four International Space Station partners and operational meteorological agencies from their respective coun- tries. It coordinates a wide range of programmatic issues relating to polar- orbiting platforms and associated free- flyers including payload planning, mission operations, data policy, and ground system coordination.

The EO-ICWG meets three to four times per year, rotating venue and chairmanship among members. It serves to coordinate and harmonize plans of members to provide instrumentation and to use polar-orbiting systems with the

aim of maximizing the scientific, operational, and applications benefits to the global user community. With respect to the NASA and ESA polar platforms that are covered by the Space Station agreement framework, the EO- ICWG includes in its Terms of Reference the mandate to develop plans to enable each member to submit an internationally pre-coordinated recom- mended plan to the relevant decision- making bodies of the International Space Station program. The ICWG has on occasion held its meetings back-to- back with either CEOS or IPOMS and has requested that the CEOS Working Group on Data address certain data management issues.

IPOMS, another coordination group created in connection with the Economic Summit's Panel of Experts on Remote Sensing, was established in November 1984 to explore mechanisms for in- creased international cooperation in support of polar-orbiting meteorologi- cal satellites and to ensure the continuation of morning and afternoon polar-orbiting satellite systems. Current members are Canada, France, the Federal Republic of Germany, Italy, Japan, the UK, ESA, EUMETSAT, the European Community, NASA and NOAA, with NOAA providing the secretariat. Topics discussed by IPOMS include instrument, space, and ground segment contribu- tions, data policy, and system con- figuration and design. Ad hoc techni- cal and administrative groups have met as needed.

IPOMS has recommended use of the polar platforms of the International Space Station as carriers for meteorological instruments, with gap- fillers and/or free-flyer satellites if the Space Station polar platforms are not able to assure continuity to operational users. In this connection, NOAA plans to provide afternoon polar continuity through a series of free- flyers, while EUMETSAT and ESA are working together to provide morning polar service beginning with the European First Polar Orbit Earth Observation Mission (POEM-I). NOAA, EUMETSAT, France and Canada plan to contribute operational instrumentation for the European spacecraft. Once European assumption of morning polar service is fully confirmed, IPOMS will have successfully completed its major task.

CGMS, formed in 1972, serves as an informal technical forumthrough which program managers of agencies pursuing plans for geostationary meteorological missions have been able to discuss common interests relating to the design, operation and use of their

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spacecraft. Current participants include EUMETSAT, India, Japan, the U.S., the USSR, the WMO and the PRC. The work of CGMS has been concerned with (i) the operational aspects of the geostationary programs, especially data processing and dissemination matters such as compatible data formats, standard transmission frequencies, compatible data collection platform standards, and complementary orbits; and (2) the technical feasibility of implementing common operational approaches from the vantage points of cost and scheduling. While the geosta- tionary meteorological satellites remain independently designed and developed, as a result of CGMS coor- dination these satellites meet certain common meteorological mission objec- tives and have produced certain com- patible meteorological data products for global users.

At the last CGMS meeting, EUMETSAT proposed the permanent expansion of CGMS activities to include discussions on the operation and planning of polar- orbiting meteorological satellites. According to the EUMETSAT proposal, this addition to the current CGMS activities would not conflict with the work of groups such as IPOMS or CEOS. The proposal would include changing the group's name to the Coordination Group on Meteorological Satellites (CGMS). The U.S. responded formally to the proposal in March 1990, suggesting that Earth observation programmatic and policy-level issues are dealt with in CEOS and noting that CGMS had previous- ly focused on technical matters. The U.S. further observed that CGMS has functioned without specific terms of reference and suggested that a charter be drafted in advance of a full discus- sion of the EUMETSAT proposal. This discussion is expected to take place at the next CGMS meeting, set for December 1990.

The Need for Scientific and Intergovernmental User Involvement

All of these international coordina- tion groups have proven useful in achieving greater complementarity and compatibility among national systems, and in some cases, in providing the impetus for specific bilateral or multilateral collaboration. No one of these groups, however, includes all of the international players with significant roles in the development of Earth observation missions. Also, while the design of most national satellite programs takes into account requirements of their own respective scientific communities and important user groups, the satellite coordination

groups have had little direct input from international scientific organizations (such as IGBP and WCRP) or intergovernmental user agencies (such as WMO, UNEP and IOC). Given the direct involvement of such scientific and intergovernmental organizations in the current international focus on global environmental issues, it is of considerable importance that their inputs be taken into account in a forum involving national and regional Earth observation agencies. Inputs from commercial remote sensing organizations are also of importance; such inputs should continue to be made through the the representation of their respective national government agencies.

A Proposal to Strengthen CEOS

Increasingly aware of the need to make existing Earth observation coordination groups more effective in addressing global change research- mandated sensor and data management requirements, NOAA and NASA have over the past year consulted with their international partners on how best to restructure these groups and the linkages among them to more capably develop the infrastructure for a coordinated global, space-based, Earth observing system. These discussions focused on CEOS as the logical forum to include representation from the scientific and intergovernmental user communities and thereby to develop the necessary consensus across the whole spectrum of Earth observation satellite missions and related data management activities. Of all existing satellite coordination groups, CEOS has the broadest scope and involves the level of management required to address necessary budget and policy issues. The notion that representatives of scientific organizations and intergovernmental user agencies should join together in a coordination forum with senior Earth observation agency officials was clearly validated in the excellent Seminar on Space and Global Environment hosted by the Government of France, June 22-23, 1990, in Paris.

In a joint communication to CEOS member agencies, NOAA and NASA in July 1990 proposed structural changes to CEOS for consideration at the upcoming CEOS plenary to be held in November 1990 in Brazil. The communication stated that the changes proposed were to strengthen CEOS interaction with both the international scientific and intergovernmental user communities. As a result, CEOS would clearly serve as the focal point for coordination of the space segment of the international

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global change effort. To this end, the U.S. agencies proposed that CEOS

o establish formal links to other satellite coordination groups (spe- cifically the EO-ICWG, IPOMS, and CGMS), inviting their participation in the CEOS Plenary;

o expand observer status to invite the active participation of international scientific, policy, and intergovern- mental user organizations with major programmatic activities that support CEOS objectives (including ICSU/IGBP, WCRP, IPCC, WMO, UNEP, IOC, and possibly other agencies with major satellite data use activities);

o consider applications for CEOS membership or observer status from those national and regional govern- mental agencies that (1) request such affiliation, (2) qualify under exist- ing criteria, (3) seek international collaboration in Earth observations, and (4) are prepared to make data from their satellites/instruments fully available to the international community;

o provide focused direction to the activities of its two working groups --the Working Group on Data and the Sensor Calibration and Performance Validation Working Group--and con- sider the chartering of additional technical working groups, in par- ticular a Working Group on Space Networks;

o increase the frequency of meetings to once a year with designated points of contact for each CEOS member and observer for ongoing coordination between meetings; and

o consider changing the name of CEOS to the Committee on Earth and Environ- mental Observations Satellites (CEEOS).

In the view of NOAA and NASA, such changes will strengthen CEOS to more ably address policy and technical coor- dination issues as they relate to satellites and data exchange. It is not intended that CEOS usurp the authority of participating agency or organization programs, or of linked satellite coordination groups. The autonomy of all such organizations would remain intact, but CEOS could greatly assist their efforts by providing a more effective consensus- building forum.

An Agenda for the Future

Given the need for a restructuring of CEOS along the lines discussed, what agenda must CEOS and other international coordination groups consider in moving toward a truly global Earth observing system? Such an agenda might include the following objectives:

Encouragement of necessary bilateral and multilateral consultations to achieve cooperation in the develop- ment and deployment of sensors that will avoid duplication and fill gaps to thereby address the full range of global change-related observational requirements. An example is the need to provide Earth radiation budget measurements in the time period between the planned French/Soviet SCARAB mission and the CERES instrument on the NASA Earth Observing System late in this decade.

o Collaboration in calibration and validation activities should also be encouraged such as long-term maintenance of test sites, both instrumented and non-instrumented, and establishment of easily accessible calibration data bases.

Earth observation and user agencies should embrace and abide by a set of data policy principles that will result in the full and open sharing of the entire suite of global data sets for research and operational "public utility" purposes with such data provided at the lowest possible cost to global change researchers and government decision-makers worldwide.

Ground-based, in-situ data must be made available for correlation with space-based Earth observation data. Examples here include the field campaigns of the International Satellite Land Surface Climatology program, the World Ocean Circulation Experiment, the Tropical Ocean and Global Atmosphere program, the Global Energy and Water Cycle Experiment, and correlations undertaken with ship measurements and drifting buoys.

The space-based data elements of Japanese, U.S. and French/Italian proposals for construction of inter- national data networks should be examined and harmonized through collaboration in which all CEOS partners have a role with access arranged for developing countries.

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o Finally, efforts must be undertaken by those countries with space assets to assure that developing country decision-makers and users benefit from operation of a global Earth observing system. In addition to availability of data at the lowest possible cost, such efforts might involve training and applications- oriented activities.

Conclusion

There already is a high degree of collaboration among space-based Earth observation agencies. Such collaboration is undoubtedly fostered by the heightened sense of urgency in dealing with global change phenomena for which space-based observations offer the advantage of both broader and closer views of our planet. International Earth observation coor- dination groups have contributed to this collaboration. It is clear, however, that the work of such coordination mechanisms can be greatly enhanced through direct participation of scientific and intergovernmental user organizations. The vision of a truly global Earth observing system-- with coordinated space-based observations complementing the acquisition of land and ocean surface data--is clearly within our reach.