March 1998

IGOS Principles
The Overall Structure of an IGOS
Processes within an IGOS
Levels of Integration
Promotion of IGOS
Figure 1: An outline of the overall conceptual structure of an IGOS
Figure 2: Main activities within an IGOS
Figure 3: Levels of integration in the current form of an IGOS


The background and rationale for an Integrated Global Observing Strategy (IGOS) has been discussed widely within the Committee on Earth Observation Satellites (CEOS) and spelt out in a number of basic documents. These include the Irvine meeting documents, particularly the one on the comparative advantage of IGOS and the subsequent scoping paper.

The potential advantages for an IGOS all basically stem from the benefits that can be realised from improved international cooperation and coordination. These benefits arise from the impossibility of any single nation providing itself with all their needed observations either because of costs in the case of space observations or logistically in the case of many in situ observations. The need for co-operation between data-provider agencies also arises from the fact that contemporary data products often require the integration of multiple observations from multiple sources.

Various attempts have been made to indicate how existing organizations such as CEOS and the Global observing systems can play a role in such an integrated strategy. This paper attempts to bring together four issues on which agreement is needed if progress is to be made in implementing an IGOS.

  1. the principles under which an IGOS should operate
  2. a description of the overall structure of an IGOS
  3. the various essential processes (or activities) that need to operate within an IGOS
  4. the need for concerted promotion of the strategy.
This paper does not attempt to identify with any degree of specificity the roles that various existing organizations should play nor have any new structures been proposed where there are no existing organizational structures. Such deliberations should be secondary to agreement on the principle and the nature of the processes occurring with an IGOS. On the basis of agreement on the principles and processes, a next step will be to use existing and, as necessary, new structures to achieve the implementation of an IGOS.


IGOS is a strategy to involve the major systems for global environmental observation (satellites and ground based) for the atmosphere, the oceans and the land in a framework that delivers maximum benefit and effectiveness in their final use.

A fundamental issue for an IGOS is the identification of what it can contribute, that cannot be achieved through existing national and international mechanisms. In short the added value of an IGOS has to be demonstrated. Ultimately, IGOS will be judged by whether it enables better observations to be derived in both a more cost-effective and more timely fashion. To succeed it has to build upon current successes, thus recognising that there are existing programmes, which already provide integration, and that these could be regarded as the basic existing core of an IGOS. De facto they are the current set of priority activities.

Basic principles of an IGOS are that it should:

  • provide a framework for a coherent set of user requirements so that providers can respond to them
  • be an overarching strategy for global observations allowing those involved in their collection to improve their contributions and make better decisions in the allocation of their resources to meet their own priorities by taking advantage of better international collaboration and coordination. These resources may be used to upgrade existing or establish new systems
  • provide a framework for decisions that have the intent of providing long term continuity and spatial comprehensiveness for key observations
  • provide a framework for decisions that will result in the scientific research needed to allow a better understanding of Earth processes
  • build upon the strategies of existing international Global observation programmes and focus the need for additional efforts in areas where satisfactory international arrangements and structures do not currently exist
  • build on existing international structures that successfully contribute to current global observations rather than create a centralized decision-making organization
  • provide improved understanding for Governments on the need for Global observations through the presentation of an overarching view of current system capabilities and limitations
  • be helpful in efforts to reduce unnecessary duplication of observations
  • provide opportunities for capacity building and assisting countries to obtain maximum benefit from the total set of observations
  • facilitate the creation of improved high level products by facilitating the integration of multiple data sets from different agencies and national and international organisations
  • identify situations where existing international arrangements for the management and distribution of key global observations and products could be improved
  • assist in the transitioning of systems from research to operational status through improved international cooperation
In striving to respond to these principles contributions to an IGOS should:
  • for key variables have the intent of providing long term continuity of measurement
  • provide adequate data archiving and access capability for all data sets
  • provide for consistency of data quality where there are disturbances to the record e.g. due to new technology
  • provide sufficient visibility of ancillary data to enable users to make judgements on the data quality

Figure 1 below indicates an overall conceptual structure of IGOS. External scientific, social, economic and political motivations at international and national levels must drive the strategy. The first stage in the IGOS is to assess the requirements for observations given these priorities. In concert, the capabilities of existing and planned observation systems need to be evaluated. Bringing together the assessment and evaluation allows an analysis to decide what needs to be changed. Commitments then have to be obtained from implementing agencies, both national and international. This is the critical phase in the overall success of IGOS.

Changing the observational systems then follows. This may result in the deployment of different observational assets or more frequently may result in alterations in the way data are collected and processed to create enhanced products better able to satisfy requirements. Products are then put to use. Accompanying the use should be a further stage of product monitoring and analyses to ensure that the observations are being acquired as planned and meet requirements as expected. This then forms a feedback loop for further evaluation of the capabilities of observational systems.

In summary an IGOS must provide the framework that will enable suppliers to be able to respond to requirements that have been set by users. It must involve processes that will determine deficiencies, enable resources to be garnered to remedy such deficiencies and be capable of improving not only the observational assets but also the various stages by which observations are turned into useful products. Finally there must be a process by which the products and observations are monitored and analyzed to ensure they are fulfilling their goals.

Figure 1 An outline of the overall conceptual structure of an IGOS


Within the overall structure of an IGOS each of these individual stages can be examined and the activities needed in each stage that are necessary for the implementation of an IGOS can be elaborated. The activities of each stage are illustrated in figure 2 and described below.

  • Assess Requirements: This necessitates establishing a consensus on what are the requirements for observations meeting specific information needs. Products need have to be defined which will respond to these needs and then the observations needed to generate these products.
  • Evaluate the current capabilities of observational systems. This needs first to involve a consideration of product capabilities and then to evaluate the capabilities of current systems against the requirement assessment.
  • Deciding what needs to be changed. This involves an analysis of the requirements and the capabilities in order to isolate deficiencies in observational systems. Implicitly or explicitly there needs to be a process of prioritization amongst the many deficiencies that such an analysis will reveal. The net result is a set of priorities for enhancements to the existing capabilities.
  • Obtaining commitments for changes. Having determined what are the priorities for change it is necessary then to establish the commitments to obtain such changes. These commitments will be made independently by the relevant national or international organizations.
  • Change the observational systems.
    • Deploying new observational assets. This would involve individual agencies agreeing to develop, deploy and maintain new assets, either in terms of satellite based or in situ systems.
    • Enhancing the product processing chain. Many improvements can be made through better exploitation of existing assets. This may involve changing the acquisition strategy or making other changes in the product processing chain. These may be in the areas of Calibration and Validation, data access and networking, the assembly of data sets, improving data archiving and product generation.
  • Monitoring and Analysis of Products and Information services. To determine whether or not the resultant observational systems are operating satisfactorily and meeting their objectives a continuous monitoring and analysis procedure is needed, which conceptually feeds back into the evaluation of current capabilities.

Figure 2 Main activities within an IGOS


Implementation of an IGOS necessarily means that many activities must be carried out in an integrated manner. However, certain activities involve very discrete and agency specific decisions that do not involve integration. For example changes in observing capabilities are an agency decision.

Figure 3 shows a view of the current status of certain elements of IGOS in terms of the level of integration. It is most likely that some of these should be more closely integrated than at present. It is however inevitable that many of these can conceivably only be quite modestly integrated. A remaining question is therefore what is the desirable level of integration and whether this is sufficient to ensure an effective implementation of an IGOS

Figure 3 Levels of integration in the current form of an IGOS


The above section has focussed on the description of the activities that are necessary to implement a global strategy. Throughout the process there is a real need to promote awareness on two fronts namely:

  • The value of implementing IGOS and hence the need for resources being made available at a relevant level
  • The benefits arising from the infrastructure that follows an IGOS in terms of its contribution to meeting the political objectives that have been set to improve the way we understand and manage the Earth.
No one agency can take responsibility for this promotion and it is incumbent on all to promote the value and need in a coherent way. This will hopefully result in resources being made available and additional countries and agencies seeing the benefit of the strategy.


This paper has set out the principles and processes of an IGOS. If these can be agreed then the specific roles and responsibilities of the partners can be discussed and set out.

IGOS Homepage  Earthwatch Homepage

Maintained for IGOS by UN System-wide Earthwatch Coordination, UNEP Geneva