Operational continuity of the global meteorological satellite network

Operational continuity of the global meteorological satellite network

John A. Leese, Peter F. Near and Claude Pastre

The global network of meteorological satellites used different forms of international cooperation during its development, and some of these forms continue. Concern about continued operation of the global network led the WMO to study the issues and to adopt a long-term policy and strategy based on a shared meteorological satellite network. Nations need to consider how to combine their meteorological and space-related organizations in a partnership role, so they can directly contribute to a future global network of meteorological satellites. Some examples are cited to demonstrate that increased direct participation is a valid and feasible objective.

John A. Leese is a Senior Scientific Officer in the World Meteorological Organization, 41 avenue Giuseppe-Motta, CH-1211 Geneva 20, Switzerland. Peter F. Noar is Assistant Director (Services), Australian Bureau of Meteorology, PO Box 1289K, Melbourne, Victoria 3001, Australia. Claude Pastre is Deputy Director, Met6orologie Nationale, 77, rue de Sevres, 92106 Boulogne-Bil lancourt Cedex, France.

The views expressed in this paper are those of the authors and are not necessari- ly the views of their organizations. This paper is a revised version of one presented at the 38th Congress of the Interna- tional Astronautical Federation, 10-17 October, 1987, Brighton, UK.

1Sir Arthur Davies, Meteorology- A Model of International Co-operation, WMO No 667, World Meteorological Organization, Geneva, 1987. 2H. Daniel, One Hundred Years of Interna- tional Co-operation in Meteorology (1873-

Continued on p 13

Meteorology is basically an observational science like the other geophysical sciences. Meteorologists have a need for frequent and accurate measurements of various elements of the atmosphere. Even more than for most other geophysical sciences, such measurements must extend over large areas of the Earth 's surface with a need for the rapid transmission of the data to meteorological centres. For example, to prepare a weather forecast for more than a few days ahead, it is necessary to obtain current data from virtually the whole globe. There is also a need for the exchange of these observations between neighbouring countries. The invention of the telegraph in about 1850 made it possible to exchange observations internationally, on a timely basis, for the first time.

The need for international cooperation between countries was recognized as a necessary condition in order to operate a successful international exchange of meteorological data. Sir Arthur Davies, who was Secretary-General of the World Meteorological Organization (WMO) from 1955 to 1979, described the First International Meteorolo- gical Congress in 1873 as the beginning of modern meteorology. 1 This is primarily because it was the first important recognition that progress in meteorology could only be achieved if the nations of the world worked together in full and friendly cooperation. This led to the formation of the In te rna t iona l Meteorological Organizat ion ( IMO), a non- governmental body, with the directors of national meteorological services conducting its affairs. Following the creation of the United Nations, the IMO was transformed in 1951 into a specialized intergovernmental agency and renamed the World Meteorological Organiza- tion.

The history of this international cooperation in meteorology is described in a number of publications, z The theme selected by the WMO Executive Council for World Meteorological Day in 1987 was 'Meteorology - A Model of International Co-operation' . 3 Professor G.O.P. Obasi presented a chronological summary of international cooperative efforts to show that meteorology serves as a model of international cooperation. 4

The establishment of national weather services combined with the longstanding and well-developed international cooperation led to many

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improvements in the science and applications of meteorology. 5 Building on such cooperation, and advances in science and technology generally, has led to a series of major developments. Improved methods of observing the atmosphere were developed. Networks of meteorological stations on land appeared; the use of merchant ships to obtain regular information from the ocean areas was introduced and, later, in some regions, special ocean weather ships came into operation. The upper atmosphere was explored in a routine manner by balloons, kites and, later, by aeroplanes, radiosondes and rockets; most recently appreared Earth-orbiting satellites for observing the Earth's atmosphere on a global scale.

Continued from p 12 1973), A Historical Review, WMO No 345, World Meteorological Organization, Gene- va, 1973. 3Executive Council, Abridged Report with Resolutions of the Thirty-seventh Session, WMO No 648, World Meteorological Orga- nization, Geneva, 1985. 4G.O.P. Obasi, 'Meteorology - a model of international co-operation. Message from the WMO Secretary-General', WMO Bulle- tin, Vol 36, No 1, 1987, pp 17-20. SWor/d Weather Watch, WMO No 183, World Meteorological Organization, Gene- va, 1966. 6J.A. Leese, 'Co-operation to achieve a global satellite system, Earth-oriented applications', Space Technology, Vol 4, No 3, 1984, pp 179-187. 7Third World Meteorological Congress: Abridged Report with Resolutions, WMO No 88, World Meteorological Organization, Geneva, 1959. SResolution 1721 (XVI), Annex I, Section C, and Resolution 1802 (XVII), Annex II, Section III on International Co-operation in the Peaceful Uses of Outer Space.

International cooperation International cooperation played a key role in the development of the present global network of meteorological satellites. This story has been described in some detail elsewhere. 6 In this paper we shall highlight some of the major elements of the different types of international cooperation.

In 1959 the WMO established a framework, through its Executive Council, to keep members informed about the uses of satellites for meteorological purposes; 7 this framework continues to the present.

The concept of a global network of meteorological satellites evolved during the early 1960s. Resolutions were adopted at the sixteenth (1961) and seventeenth (1962) sessions of the General Assembly of the United Nations on international cooperation in the peaceful uses of outer space, s In particular, the General Assembly recommended that the WMO study how developments in outer space could be used to advance the state of atmospheric science and technology. The WMO responsed by establishing the World Weather Watch, and also set out the necessary conditions for the optimum use of meteorological satellite systems and addressed various proposals for atmospheric research to which satellite data were expected to make a contribution.

The Co-ordination on Geostationary Meteorological Satellites (CGMS) is an informal international body made up of countries and agencies which are operating, or have firm plans to operate, geostationary meteorological satellites. This presently consists of the European Space Agency (ESA), India, Japan, the USA and the USSR. The WMO has participated in the activities of CGMS from the first meeting in 1972. The result has been a network of geostationary satellites which operate in a well-coordinated manner.

Meteosat was developed, built, launched and operated by the European Space Agency. This consortium has contributed the Meteosat-1 and Meteosat-2 satellites with the latter now operating in a vicinity of 0 ° longitude. Eumetsat, the European organization for the exploitation of meteorological satellites, was formally established in June 1986. This intergovernmental organization, founded by 16 European states and their national meteorological services, has taken over the responsibility for the Meteosat Operational Programme from the ESA. Construction of satellites and operation of the ground facilities will continue to be managed by the ESA.

The USA, in operating the NOAA polar-orbiting satellites, cooper- ates with France and the UK. The Argos satellite data collection and platform location system is provided by the French National Centre for

S P A C E P O L I C Y February 1989 13

Olwrational continuity ¢~/" the global meteorological satellite network

Space Studies. Data from the platforms are transmitted to the Argos centre in Toulouse for processing and platform location. The processed data are then sent to the user and, if appropriate, are transmitted on the WMO Global Telecommunication System (GTS) as part of the voluntary data exchange. The UK provides the Stratospheric Sounding Unit (SSU) which is one of the three sensors that make up the Tiros Operational Vertical Sounder (TOVS) system used to produce atmospheric vertical temperature profile observations over the globe. These observations are also transmitted over the WMO Global Telecom- munication System and form a significant part of the initial data set used in numerical weather prediction.

This brief summary illustrates that there are a number of different components to the international cooperation which contributed to the development of the present global network of meteorological satellites. These include:

• global coordination of the overall network including the definition and coordination of worldwide practices, exemplified by the WMO's role;

• informal coordination of scientific and technical elements of the meteorological satellite systems as exemplified by the CGMS;

• contributors of satellites to the global network as exemplified by the nations operating satellites or Eumetsat.

~ J ~ . l ~ ~ Sub-satellite ~ : ( ~ ~ point

Polar orbit

Present meteorological satellite network

Meteorological satellites have become a critical source of data used in the preparation of weather forecasts and warnings of severe weather over land and sea. The existing network of meteorological satellites, forming part of the Global Observing System of the World Weather Watch, regularly produces real-time weather information and is shown in Figure 1. The information is acquired several times a day through direct broadcast from the meteorological satellites received by more than 1000 stations located in 125 countries.

There are two major components in the current meteorological satellite network. One element is the various geostationary meteorological satellites, which operate in an equatorial belt and provide a

Figure 1. Present global network of polar-orbiting and geostationary meteorological satellites.

14 SPACE POLICY February 1989


continuous view of the weather from roughly 70°N to 70°S. At present there is a satellite at 0 ° longitude (operated by the ESA), a satellite at 74°E (operated by India), a satellite at 140°E (operated by Japan) and satellites at 135°W and 75°W (operated by the USA). A satellite is planned to be added by the USSR at 76°E. All the present geostationary satellites collect data in the visible portion of the spectrum and in the infrared 'window' from 10.5 to 12.5 ~tm. Several also collect data in other spectral intervals, especially in the water-vapour interval from 5.7 to 7.1 ~tm. Spatial resolution varies among the different spacecraft, ranging from 1 km to 5 km in the visible and from 5 km to 11 km in the infrared.

The second major element comprises the polar-orbiting satellites operated by the USSR and the USA. The 'Meteor-2' series has been operated by the USSR since 1977.

The polar satellite operated by the USA is an evolutionary development of the Tiros satellite, first launched in April 1960. The NOAA series, based on the Tiros-N system, has been operated by the USA since 1978. These spacecraft provide coverage of the polar regions beyond the view of the geostationary satellites and fly at altitudes of 850 to 900 km. Data acquired by the various sensors are handled in two ways by the on-board processors of the polar-orbiting satellites. Since the spacecraft are in view of their ground stations no more than once per orbit (and sometimes not at all for several orbits), it is necessary to record the data on tape for later playback when the spacecraft comes into view of a ground station. At the same time that the data are being recorded, the spacecraft is broadcasting them for the use of any properly equipped receiving station within range.

Together, the polar-orbiting and geostationary satellites constitute a truly global meteorological satellite network. Further details about the meteorological satellites are available in a WMO publication. 9

91nformation on Meteorological Satellite Programmes Operated by Members and Organizations, WMO No 411, World Meteorological Organization, Geneva, 1975, with Supplemental updates. mExecutive Council, Abridged Report with Resolutions of the Thirty-second Session, WMO No 556, World Meteorological Orga- nization, Geneva, 1980. 11 Executive Council, Abridged Report with Resolutions of the Thirty-fourth Session, WMO 599, World Meteorological Orga- nization, Geneva, 1982. ~2Report of the Second United Nations Conference on the Exploration and Peace- ful Uses of Outer Space (Unispace-82), Vienna, 9-21 August 1982, A/CONF. 101/ 10, United Nations, 1982. ~3Ninth World Meteorological Congress: Abridged Report with Resolutions, WMO No 615, World Meteorological Organiza- tion, Geneva, 1983. ~4Tenth World Meteorological Congress: Abridged Report with Resolutions, WMO No 681, World Meteorological Organiza- tion, Geneva, 1987. ~SSecond WMO Long-term Plan, Part 1: Overall Policy and Strategy (1988-1997), WMO No 690, World Meteorological Orga- nization, Geneva, 1988.

Need for assured satellite continuity

During the 1980s there has been great concern about the reliability and continued operation of the global network of meteorological satellites. The WMO Executive Council session in 1980 urged members to explore possibilities for future international or multilateral collaboration as an appropriate method for financing operational systems, to help assure continuity of satellite data.l° In 1982 the Executive Council stated that the overall value of the global satellite network to operational meteorological, hydrological and oceanic services had increased to such an extent that extraordinary steps may have to be taken to assure continued operation. 11

The question of the operational meteorological satellite system was discussed in several sections of the Unispace-82 conference. ~2 The conference recommended that the WMO undertake a study of how better to assure the continuous availability of and access to meteorological satellite data. The Ninth World Meteorological Congress endorsed this recommendation, 13 and the WMO completed a two-year study of this problem in 1986 which was considered by the Tenth WMO Congress in May 1987 from the viewpoint of long-term policy and strategy. TM The Second WMO Long-term Plan, which includes the period 1988 to 1997, takes up the issue of satellite continuity and includes the adopted policy statement. 15

S P A C E P O L I C Y February 1989 15

Operatiomd conlinuity of the global meteorological .~ale/li/~' Hctw~)rk

The fundamental problem is how to assure the continued and reliable availability of meteorological data and services from satellites to the worldwide user community. Achieving reliability and continuity ol global satellite coverage is particularly pertinent for the large number of countries who are neither satellite operators nor members of a consortium operating meteorological satellites. It is also very pertinent for the large parts of the globe that fall outside national jurisdiction, especially the large open ocean areas.

Problems, principles and considerations for a solution

Space technology has brought a technically viable solution to the problem of global observations in a manner that could not have been otherwise achieved. The cost of this technology, and the fact that it is not available in all nations, has brought new and difficult problems to the foreground. These problems are briefly:

Q Strategies need to be developed to ensure the continued and reliable operation of a network of satellites which will provide a common set of data and services to the worldwide user community.

• Acceptable and practical means need to be identified for nations to participate in a cooperative network on a global scale.

• Participation must include both the definition of a global network and the maintenance of its operation over a long time period.

The WMO study considered the overall problem of operational satellite continuity from the viewpoint of the technical, economic and organizational issues. Several basic principles were used to provide guidance in analysing these issues:

• continued free exchange between WMO members in accordance with approved procedures and within the limits of the agreed World Weather Watch system;

• availability of adequate redundancy and back-up to take into account the recognized fact that operational meteorology is now strongly dependent on observations from space;

• close and collaborative ties between meteorological services and space agencies to facilitate the development of new technologies and of new observing capabilities.

Economic considerations

On the basis of the minimum requirements of five geostationary and two polar-orbiting satellites for the space-based subsystem in the World Weather Watch, the total annual operating cost is several hundred million dollars per year. The largest percentage costs are the spacecraft and launch elements of the satellite system. These two elements constitute about 60-70% of the average annual costs for the meteorological satellites. These elements are crucial if future meteorological satellite costs are to be kept within reasonable limits. This may be done by sharing the spacecraft and launch with other missions such as communications or compatible remote sensing activities, or by the development of a capability to repair or replace instruments on board the spacecraft.

Three different economic approaches are being used to build and operate the current network of meteorological satellite systems. For the purposes of this paper, these approaches are labelled as:



• 'national system', where all costs are borne by the country operating the satellite system; such systems include the GOES (USA), GMS (Japan), Insat (India) and Meteor (USSR);

• 'national with bilateral contributions' - the Tiros-N/NOAA satellite system is an example of this economic approach with France, the UK and Canada providing contributions in kind to the spacecraft payloads;

• 'multinational system' - Meteosat (ESA/Eumetsat) is a multinational system where costs are distributed by formal agreement among members of an international organization.

The three economic approaches summarized above were very successful in developing the global network of meteorological satellites which operated during the Global Weather Experiment in 1979. Indeed, members of the WMO continue to reap benefits from these efforts. It is the economic problem of sustaining this network as a continuous and reliable operation which is the fundamental issue to be solved. The continuing operation of meteorological satellites poses a considerable financial burden on satellite operators. The concentration of costs among the few WMI members is a major deficiency in the current network of meteorological satellites.

It is true that the national systems with voluntary contributions to achieve a global capability are entirely consistent with the principle of voluntary contributions, which is the basis for the present World Weather Watch. However, the cost to operate and maintain a meteorological satellite system is so large, relative to costs for other portions of the World Weather Watch, that it places a disproportionate financial burden on those few WMO members who are also satellite operators. The international system, with formal agreements on how the meteorological satellite system is to be financed, could alleviate the economic problem. However, the current satellite operators have significant national considerations and needs which must be met by the satellites they now operate. They are probably not willing fully to integrate an internationally funded system with their national system. Furthermore, it is too expensive to continue a separate system for national needs while contributing to a separate international system.

The WMO could set forth some broad policy for an economic approach which would provide a basis for its members to participate and contribute to the development and operation of a global meteorological satellite network. Some form of a 'Shared Metsat Systems' approach needs to be adopted as the economic theme for the WMO to achieve a global meteorological satellite network. Such an economic theme, as a basis for a WMO policy, can encourage many different forms of cooperation. The use of the word 'shared' rather than 'cooperative' in a WMO policy for economic development of a global meteorological satellite network should convey the idea of providing a means for more equitable cost distribution among members. It also refers to the possibility of sharing a platform with non-meteorological missions. The 'Shared Metsat Systems' approach can encompass all three of the present economic approaches under a single umbrella. Defining the policy to include two critical goals of more equitable cost distribution and increased direct participation among WMO members should stimulate all interested nations to investigate how they can best carry out such a policy.

SPACE POLICY February 1989 17

Operatiom~l con/inuity of the global meteorological ~'atcllite m'tw~)rk

Organizational considerations

From the viewpoint of a global meteorological satellite network, o11~ can state the following set of requirements to serve as a bt~sis 1o~ evaluating alternative organizational systems:

• Facilitate the achieving of worldwide international agreement oll the functional characteristics of the global network.

Q Facilitate obtaining agreement on technical characteristics between the national or international entities participating in the procurement of hardware and operation of a system or systems.

• Provide for coordination of the work of those entities and adequate means to receive and use contributions, if any, from entities not participating in the procurement of hardware or operation of systems.

• Ensure the preservation of motivation and capability for continuing progress in space instruments for meteorology; ie, ties between a research community and a space organization.

• Preserve the national interests of partcipants by limiting access to sensitive technology (where required) and by providing adequate control over national investments to maximize the knowledge base and industrial return.

Four organizational models were chosen for analysis which had sufficiently distinct characteristics from each other:

• CGMS: an informal organization set up to coordinate and rationalize programmes in geostationary meteorological satellites;

• WMO: an intergovernmental organization established through government ratification of a formal convention;

• Eumetsat: an intergovernmental organization established through government ratification of a formal convention with membership available to those willing to contribute technical capabilities and financial resources towards a meteorological satellite system;

• lntelsat: an intergovernmental organization established to provide global communications satellite services to the world community.

It was found that all of the organizational models excluded one or more of the global or national criteria along with some of the specific requirements that such an organization must meet. It was concluded that international management of meteorological satellites on a global scale is premature at this time. Instead, one needs to consider an organizational system which consists of both the formal intergovernmental components and the informal cooperative components. Such a multicomponent organizational system recognizes existing arrangements and organizations, but places them within a coherent conceptual framework.

Technical considerations

Many countries now have the technical capability to develop, launch and operate a meteorological satellite, and industrial groups exist in other nations which could benefit from participation in such an activity. Ways need to be found for these countries to participate directly in both the development and operation of the global network of meteorological satellites. Nations need to consider where and how they can combine the meteorological services and the space-related organizations of their countries in a partnership so they can directly participate and contribute



to a future global network of meteorological satellites. In addition, benefits to industry as well as to meteorological services will need to be stressed when seeking funding from national budgetary authorities.

Major technological developments are expected to take place over the next 10 years and create opportunities for operating the polar- orbiting and geostationary meteorological satellites which are discussed in later sections.

A shared Metsat network

The current network of meteorological satellites offers several working examples of the activities needed for a shared meteorological satellite network. The USA provides a NOAA satellite and associated ground- based subsystem for sensor payloads provided by France and the UK. The exact arrangements for each of these activities are specified in the bilateral agreement between the USA and the contributing country. Eumetsat is another operating example wherein the sharing is done through a formal arrangement among all the members of the international organization. The two examples cited are each providing the means for more equitable cost distribution and increased direct participation for a coordinated global network. Several other possibilities for participation will be found in both the geostationary and polar-orbiting systems.

Opportunities in polar orbit

Until quite recently only the USA and USSR were providing observations of the Earth from polar orbit, most of the pioneering work in this field having been done by the USA since 1960. SPOT, a French satellite dedicated to land observation, along with the Marine Observational Satellite (MOS) launched by Japan for ocean observation, mark a change in this situation and illustrate the growing potential for international involvement.

During the next decade a number of satellites will provide data from experimental missions for the oceanic areas. Among those will be MOS-1, already launched by Japan, ERS-1 (Europe) and Topex- Poseidon (USA/France). Once these satellites have demonstrated their value in meteorological and oceanographic analyses, the same 'user pressure' will appear as existed after the experimental stage of present operational systems. The need will occur for countries or institutions to finance and operate continuously for 10 years or more the kind of instruments flown on these experimental satellites.

The concept of the space station programme that the USA, Japan and the ESA are at present discussing may open opportunities for participation. This programme includes plans for several platforms in polar orbit, potentially seviceable, with large capacity for instruments on each platform. From the outset partners in the system will have the possibility of proposing instrumentation for the system. There is no a priori reason why they could not do that in cooperation with countries outside the initial circle of partnership. In a future phase, one could well imagine that the system might be directly open to international participation if it has sufficient capacity. Even if the polar element of the space station programme were to encounter difficulties for technical or financial reasons, the hopes it will have generated will be sufficient to


Operational continuity of the global meteorological .satHlite network

provide momentum for increased international cooperation for observation in polar orbit. The informal group for coordination of Intcrnational Polar Orbiting Meteorological Satellites (IPOMS) could continue it~ drive for completeness and continuity of meteorological observations from polar orbit.

Ground systems and data processing present another domain ot opportunity. In this area, the situation cannot remain unchanged when one goes from national to international systems. The amount of data to be processed, exchanged and used in applications will increase by several orders of magnitude for several reasons: new measurements, increased resolution, all partners requesting access to the same quality of data and service.

Potential strategies in geostationary orbit

Several strategies can be considered to achieve a high reliability and continuity of coverage for a global network of geostationary meteorological satellites:

• a dynamic network based on redeployment of operational satellites; • moveable spare satellites operated to support neighbouring satel-

lites when failures occur; • a 'fail-soft' network based on overlapping coverage from operating

satellites.

In the first strategy, we hypothesize that the geostationary meteorological satellites all have some capability to make adjustments to their operating position when one of the other satellites fails. In other words, we assume that we can achieve a high degree of reliability and continuity on a global scale by using only a strategy of redeploying operational satellites from their normal operational position. We find, after many years of operations, that there are a number of factors which bring strong pressure to keep the operating position fixed. The users increasingly prefer to keep the satellites operating at fixed positions. In addition, the multidisciplinary combination of geostationary satellites, such as Insat, can have very stringent requirements for keeping the satellite operating at a fixed position for the communications and broadcast missions.

The strategy of a dynamic network, wherein reliability and continuity of coverage from a global network is dependent on redeployment of operational satellites, has limited utility due to the inability to rationalize the needs for geographical coverage by different users and the presence of different types of spacecraft.

The second strategy hypothesizes that all operating satellites will occupy a relatively fixed position in a global network. A cooperative arrangement or set of arrangements will be established among the satellite operators to provide a spare satellite system(s) which could provide some coverage for a failed satellite within a short time period. In this case, it is necessary to consider how the data from one operator's satellite can be provided to the users of another operator's satellite. The choices in this case are either to modify the ground data handling system so that data from another satellite can be used or to modify the data format coming from another satellite to fit the ground data handling system. The relative size of the two approaches, combined with the fact that the communications function normally continues operating longer


SOp cit., Ref 14.


than the remote sensing function, seems to present strong arguments in favour of modifying the data format. Increasing the reliability and continuity of coverage from a global network in the near term of the next 10 years is heavily dependent upon the present set of satellite operators. The strategy of using a moveable spare satellite could significantly enhance the reliability and continuity of data and services from geostationary satellites during the period.

The third strategy hypothesizes that all areas of the global network are covered by two operating geostationary satellites. In the event that an operating satellite fails, the ground data handling system can be shifted to the neighbouring satellites in a short period to maintain continuity of data coverage and services. Arrangements are completed in advance so that a pre-established set of data and services can begin from the neighbouring satellites very soon after a satellite has failed.

One needs to consider that a larger number of operating satellites provides opportunities to achieve overlapping coverage. This type of coverage can provide back-up for at least a portion of the region covered by each satellite. Thus, one can consider having a 'fail-soft' system for those portions which have overlapping coverage. It should be noted that 10 operating satellites at appropriate locations can provide full overlapping coverage for a global network. However, consideration for national and regional requirements will increase the number of satellites needed for full overlapping coverage.

The strategy of overlapping coverage with a resultant 'fail-soft' global network can provide maximum reliability and continuity. This is a strong reason for promoting increased direct participation in geostationary meteorological satellite operations, especially among countries now considering such possibilities.

Increasing the number of direct participants

Several countries are already planning to launch and operate satellites which can provide data and services for meteorology. In this regard, China and Brazil each announced their plans for satellite launches at the Tenth World Meteorological Congress. 16 China plans to launch an experimental polar-orbiting meteorological satellite prior to 1990. Brazil is planning to launch an experimental satellite with a data collection mission before 1990.

As a long-term strategy the key approach for achieving stability of operational services is to encourage the contribution of participants in the global meteorological satellite network. Continuity of operations is dependent on securing long-term commitments of contributors to the global network. There exists a number of examples which demonstrate the ability of meteorological services and space-related organizations to form a partnership in applying space technology to meteorology. We shall summarize the two examples of India and Australia to illustrate two approaches which are being used successfully.

The Insat satellite

With respect to geostationary satellites, the Insat satellite, operated by India provides an example of direct participation in the meteorological satellite programme. In this case the meteorological mission has been combined with telecommunications and television missions on the same satellite through the type of cooperation between meteorological, space


Operalional ~'oltliHttily o[" lhe glohal meleorolo~i¢'al sate'/hie tte/w~rk

and other agencies referred to above, and fostered through the ',|cti\rc encouragement of the Indian government. The meteorological components of the satellite, which is three-axis stabilized, comprise:

• a two-channel very high resolution radiometer for imaging thc Earth's cloud cover; and

• a transponder for receiving data from data collection platforms and relaying them back to the central data processing facility.

As part of the Insat meteorological applications programme, the India Meteorological Department has implemented a disaster warning system for the efficient and reliable dissemination of warnings against approaching cyclones. Only a limited subset of Insat data is presently being disseminated internationally, since the satellite does not have a global direct broadcast facility like the other geostationary meteorological satellites. However, this issue is being actively pursued and improvements should be forthcoming from the meteorological portion of the Insat system as the resources become available.

It is expected that other countries will evaluate the approach adopted by India for possible application on a wider scale.

A ustralia: moves towards greater direct participation

In Australia there has been increased collaboration, particularly during the past two years, between meteorological, space, communications and general research authorities. Australia now owns and operates a series of geostationary communications satellites, (Aussat 1 and 2) located at 160°E. An investigation was undertaken of the possibility of mounting a meteorological sensor on the de-spun portion of the communications satellite; the next in the series is due to be launched in 1991. On the basis of cost, weight and timescale, such a configuration is not feasible until perhaps the late 1990s.

The Australian Bureau of Meteorology has taken a number of preliminary initiatives towards greater direct participation, and has taken the position that although it would be a major operational user, the data from such a shared satellite would form an integral part of the global network. Potential operational users would include not only countries in the satellite's field of view, but all interested countries. It is considered important that any proposal be developed to complement and support the policy of free exchange of meteorological data. Tangible support from other countries would be requested in the form of joint development and funding.

Relevance to industry. Moves towards increased direct participation conform well with a report entitled 'A Space Policy for Australia', produced by a Committee of the Australian Academy of Technological Sciences. Relevant to the present discussion are:

• R 5 - Active pursuit of the possibility of international collaboration in space and in particular joint space initiatives with other countries in the East Asian Region.

• R 8 - First phase of an Australian space programme should have the objective of achieving in industry the capability to participate in the development of complex spacecraft either as a sub-contractor or with prime contractor responsibility for a major system.

• R9 - The space segment of the national space programme should be directed towards development of Earth resources spacecraft equip-



ment suitable for inclusion in other nations' spacecraft or at some future time in a spacecraft of Australian origin.

Possible Australian configuration. A concept has been developed involving the Commonweal th Scientific and Industrial Research Orga- nization (CSIRO) and the Australian Bureau of Meteorology for a remote sensing package to be flown on a geostationary satellite over the Australian region. The major elements of the concept, which has involved a combination of optical expertise from CSIRO and meteorological expertise from the Bureau and CSIRO are to fly an instrument to obtain high-resolution imagery at various wavelengths of the infrared, involving an 18 ° x 18 ° scan of a complete Earth disc over three to four hours, together with another scanning mode over perhaps 4.5 ° x 4.5 ° over 15 minutes. The scan rate at both modes would be identical. An important feature of the package would be to mount a mirror of sufficient size and quality which would be capable of driving meteorological and oceanographic detectors for both very high resolution imagery and vertical temperature soundings. Various possibilities exist for deployment, and these would be common to all or most countries contemplating greater direct participation in the operation and/or deployment of meteorological satellites.

Options for deployment. Several options may be set down:

• Add a sensor package on one of the next generation of Aussat telecommunication satellites.

• Incorporate a sensor package to be flown on a specifically dedicated non-telecommunications satellite operated by the Aussat Corpora- tion.

• Launch a sensor package on a fully dedicated meteorological and remote sensing satellite.

• Seek the involvement of other countries in joint development and funding.

The sensor payload would be mounted on the de-spun portion of a spin-stabilized satellite for reasons of stability and pointing accuracy. If the instrument package is to be flown on an Australian satellite, it is likely that could occur before at least the late 1990s. Because of their geographic affinity, joint development with Japan or China is an obvious possibility. Australia enjoys close ties with both countries and a collaborative effort within the framework of free and open exchange of data would be of general benefit. The first possibility of collaborative effort with Japan is with GMS-5, due to be launched during the first half of the next decade. A survey is being conducted by Japan to start to develop a design concept for GMS-5. Such a study would provide an opportunity for countries such as Australia to provide further details of proposals they might have. Clearly there is a developing climate for increased direct participation by such countries and a number of avenues are being explored ranging from multimission national satellites to contributions (early instrumentation or back-up satellite) from other nations. Such efforts will probably reach fruition during the mid to late 1990s.

Concluding remarks The history of international cooperat ion in meteorology, spanning more


Ol~erational cotttinui 0 o[ the global meteorologi~'a[ ,~ate[lil~' network

than a century, has established ~t solid foundation for the continued development of the field. The vision to create and succcssfull~ implement the Global Weather Experiment in 1979 brought a global network of meteorological satellites into being, which now operates on the basis of voluntary exchange of data through international cooperation. Meteorologists are now being challenged to create the infrastruc- ture needed to sustain a reliable and continuous operation of a global network of meteorological satellites. One of the key elements in the near term involves seeking a consensus on an overall global satellite network configuration which combines all the participants' contributions.

In summary, the key economic and organizational elements needed to assure long-term continuity of the global network of meteorological satellites are increased direct participation to achieve more equitable cost distribution, and an organizational system which consists of both formal intergovernmental components and informal components. Opportunities exist to expand the number of direct participants in the global network of meteorological satellites through a partnership between the meteorological services and space-related organizations in an increased number of countries, with several countries now actively pursuing this course of action.


Documents

Operational continuity of the global meteorological satellite network