In Situ Observations for the Global Observing Systems

Development of an integrated strategy and identification of priorities for implementation
10-13 September 1996, Geneva, Switzerland

The full version of this document is available from or in hard copy form as GCOS-28 (WMO/TD-No.793)(UNEP/DEIA/MR.97-3) In Situ Observations for the Global Observing Systems (Geneva, Switzerland, September 10-13, 1996)


Integrated Recommendations and Summary of Conclusions
Data collection and assembly
Calibration and validation
Data management
Interactions between the global observing systems
Common issues for the global observing systems


In situ observations are crucial to the success of the three global observing systems, specifically the Global Climate Observing System, the Global Ocean Observing System and the Global Terrestrial Observing System. This report summarizes the results of an international meeting co-organized by the three global observing systems held in Geneva, Switzerland, that considered strategic issues relating to the collection of these observations and specifically to the identification of priorities relating to climate requirements.

In addition to recommendations on specific technical issues concerning the collection and management of in situ observations, the meeting also considered many aspects of the inter-relationships between the observing systems and other international organizations. It was recommended that the Committee on Earth Observation Satellites enhance the activities of its Calibration and Validation Working Group so that it can be more responsive to the needs of the three global observing systems.

Since this was the first joint meeting of all three observing systems on any topic, several recommendations were made concerning joint approaches to their activities including common approaches in ensuring the collection of long-term consistent observations and in defining priorities.


Development of overall strategies for observations of the Earth system has received considerable attention over the last two years. Most attention has been paid to space-based observations, but of comparable importance is the wide variety of in situ observations made at the surface of the Earth and in its atmosphere and oceans. By in situ observations we refer to those observations made as a result of direct measurement at a site: some observations will be made directly, possibly by automated means, whereas many others may be made in the laboratory on samples taken from a site. A joint meeting co-sponsored by the Global Climate, Ocean and Terrestrial Observing Systems (GCOS, GOOS and GTOS) was convened to examine the extent to which observational capabilities match needs and to determine what are the key actions needed to remedy deficiencies in current systems.

In some fields, the last ten years have seen considerable improvements in the acquisition of in situ observations, but other in situ observational systems have suffered serious decline. Some global in situ observational systems are well organized and function very successfully. But there are important in situ observational systems, such as those relating to terrestrial ecology, lacking comprehensive international coordination of global observations.

The meeting concentrated on strategic issues and identification of priorities relating to climate requirements for global in situ observations and products, including those for climate prediction services, climate research and assessment of climate change. It was based on requirements as outlined in the existing plans (e.g., GCOS 1995a, Ocean Observing System Development Panel 1995, ICSU/UNEP/FAO/UNESCO/ WMO 1996) of the three observing systems (GCOS, GOOS and GTOS).

The three global observing systems already have a number of mechanisms for ensuring coordination of their strategies. There are the two joint design panels, namely the Ocean Observation Panel for Climate (OOPC) and the Terrestrial Observation Panel for Climate (TOPC), the first of which is developing the ocean component of GCOS and the climate component of GOOS and similarly the TOPC is developing the terrestrial component of GCOS and the climate component of GTOS.

Recently it has been decided to expand the scope of the Space-based Observation Panel of GCOS to include the interests of GCOS, GOOS and GTOS and there are proposals in hand similarly to expand the scope of the GCOS Data and Information Management Panel.

The meeting's objectives were to carry out the following:

- Provide an overview of the principal internationally coordinated in situ observing systems, mainly by identifying and reviewing critical deficiencies in current in situ observations using the plans of the three global observing systems to identify requirements;

- Assess future in situ requirements on the basis of these plans;

- Review the status of in situ observations vital for the support of space observations;

- Develop a strategy to remedy deficiencies, based on existing mechanisms and networks;

- Review the status of data management systems;

- Identify deficiencies in the organizational arrangements for the collection assembly and distribution of observational data sets;

- Consider the position of in situ observations in relation to other strategies such as those for space in the "integrated global observation strategy".

In situ observations at a global scale are often inadequate for several reasons including the following:

- Lack of precision and accuracy, arising through factors such as inadequate instrumentation, lack of skilled personnel and inadequate maintenance;

- Inadequate sampling in space and/or time;

- Incompatibility of observations, for example by the use of different instruments, different timing of observations and different methods for recording the data;

- Inadequate assembly of observations globally often due to a lack of data management but also for some observations, because of national sensitivities about the use of observations relating to national resources.

The reasons for such deficiencies apart from the more obvious technical ones are not difficult to identify. They include inadequate data management locally, nationally and internationally, deficiencies of international coordination mechanisms to ensure that collected observations are assembled into global data sets and of course insufficient financial resources.

Given the heterogeneity of in situ observational systems it is appropriate to question why a strategic oversight for in situ observations is needed. Firstly there is the fact that many in situ observations are irreplaceable in that they are not substitutable by remote sensing observations and have to be maintained for an understanding of climate. However some of these in situ systems are deteriorating. Also many new techniques for in situ observations are becoming available, which may compete with existing systems to the possible detriment of consistent long-term observations. In many areas resources are becoming increasingly constrained, so that choices may have to be made between different observational systems. The latter is one of the main drivers behind the increasing desire of some governments to establish observational priorities with the framework of an overall integrated observational strategy. Finally it is clear, that for globally relevant in situ observations to be collected, many different nations and organizations have to be involved in planning and implementation and a coordinated approach has to be developed.

Strategies are needed to establish requirements in a consistent fashion, to assess priorities and to achieve implementation. This poses considerable challenges. For example prioritization is difficult within observing systems and setting priorities between observing systems may be very difficult indeed. But if the global observing systems do not establish priorities others, outside or peripheral to the global observing systems or charged with implementing systems, certainly will do so.

In some ways it is becoming more difficult to demonstrate the benefits of improving or maintaining observations because of the complex way in which observations are processed to generate the products required by users. For example products are often derived by integration of in situ and remote sensing observations. Four dimensional assimilation techniques are increasingly used to create more consistent data sets, but this may make it difficult to track the contribution of any individual observational component. Also there is the fundamental problem that data quality is highly dependent on the specific application of the data: new applications may often reveal new deficiencies and hence quality and data deficiencies are dynamic attributes of data sets.

Achieving implementation of the plans of the global observing systems whether for in situ or for space observations will prove a difficult task. For this to be possible it is important to ensure that national governments, who provide funding, have a better understanding of the importance of in situ observations through a comprehensive understanding of requirements and capabilities. Of equal importance is that they understand the benefits of these observations and the advantages of international cooperative efforts in their assembly and use. Simply asking for improvements, which demand additional resources, will usually be unsuccessful. There is a need to demonstrate the vital need for improvements, their impacts in terms of use, and their feasibility especially in terms of cost-effectiveness. The latter will be assisted by the strengthening of existing organizational structures and mechanisms, for example through closer collaboration between the global observing systems.

Some mechanisms for implementation already exist. For example, through the World Meteorological Organization (WMO), there exists a process whereby the permanent representatives of member countries can be formally approached seeking their cooperation in collecting new or improved observations following a systematic process of developing, evaluating and vetting proposals from organizations such as GCOS. But for some in situ observations there is no existing international agency responsible for such coordination, for example for the global network of ecological test sites proposed by the TOPC. In such cases it will be important that an appropriate international agency takes on an international coordinating responsibility. Sometimes networks with operational responsibilities emerge from prototype research observational systems, such as the Tropical Atmosphere Ocean (TAO) array, but the transfer from research programme to operational programme may be very lengthy.

Improving the quality of in situ observations will be a complex and difficult set of tasks. The report of this meeting is intended to provide an initial overview of requirements, capabilities and the steps needed to improve the most important elements.

Integrated Recommendations and Summary Of Conclusions

The following sections outline the presentations, conclusions and discussions of the meeting as prepared by writing teams during and immediately after the meeting. Inevitably several of the recommendations from the different sessions overlap. Consequently this integrating section is included to draw out the main conclusions of the meeting and to form an executive summary. The source of the recommendations is indicated as follows:

- Atmospheric session's recommendations have the prefix A.
- Oceanic session's recommendations have the prefix O.
- Terrestrial session's recommendations have the prefix T;
- Calibration and validation session's recommendations have the prefix C;
- Cross-cutting session's recommendations have the prefix X .

Data collection and assembly

Because of the strategic nature of much of the meeting there was less emphasis on recommendations concerning the creation of specific data sets than would be the case in thematic meetings on particular observations. The latter are described in varying degrees of specificity in the reports of the observing systems and their panels. Nevertheless a number of key requirements relating to the improved collection and assembly of data sets were made:

The WMO should consider ways of expanding and improving the aircraft observing scheme to include additional aircraft as well as new parameters such as atmosphere moisture and carbon dioxide (Recommendation A4).

The WMO should make available updates of baseline data sets such as the Comprehensive Ocean Atmosphere Data Set (COADS) on a regular basis (Recommendation A3).

The GCOS Joint Scientific and Technical Committee (JSTC) should facilitate the enhancement and development of a global database on aerosol characteristics appropriate to quantify regional and global climate forcing (Recommendation A10).

Sensors and systems (e.g., acoustics and optics) which can provide key Living Marine Resources (LMR) data should be included on other platforms (e.g., moorings and Volunteer Observing Ships) to provide concurrent, complementary and economical information about LMR (Recommendation O7).

The effective implementation of the LMR module depends on the development of a more timely and effective system for gathering and collating fish stock data. It is recommended that opportunities within the global observing system process be sought in order that such a system can be put into place (Recommendation O8).

WMO through the Hydrology and Water Resources Programme (HWRP) should periodically contribute to an assessment of the state of the hydrological networks (Recommendation T1).

Given the lack of availability of many types of hydrological data GCOS and GTOS should immediately contact the FRIEND (Flow Regimes from International Experiments and Network Data) office to take advantage of the offer of this programme office to help make their data available to a wider community. Making such data available on the Internet should encourage others to make their data available as well. In addition GCOS and GTOS should establish Internet links to the vast amount of US Geological Survey data that is already available (Recommendation T2).

In the context of sampling devices for hydrological measurements WMO should continue to support inter-comparison studies and work towards standardization to the maximum extent possible (Recommendation T3).

The TOPC should develop a global demonstration project to test the ability of GTOS to deliver a needed terrestrial product rapidly and cost effectively. Soil carbon and its associated variables might be an appropriate test case (Recommendation T5).

Calibration and validation

The importance of calibration and validation of both in situ and remote sensing observations was a recurrent theme of the meeting. Specifically the importance of in situ observations in calibrating and validating remote sensing observations was recognized.

A cross-sectoral approach to calibration and validation of remote sensors with in situ data is recommended, because for several sensors, applications cross the boundaries of the global observing systems and their components. Merged satellite-in situ products are proving more useful than either of the individual (remote or in situ) products (Recommendation O5).

The meeting endorsed the recommendation from Working Group on Calibration and Validation (WGCV) to the Committee on Earth Observation Satellites (CEOS) plenary concerning cross-calibration activities and establishment of test sites (Recommendation C6).

Interactions of the global observing systems with the CEOS Working Group for Calibration and Validation were identified as being of particular importance. Two recommendations are of particular relevance to the new Space Panel serving the needs of all three global observing systems.

Recognizing that all the global observing systems will soon be affiliates of CEOS, the global observing systems should coordinate their participation in CEOS though the Global Observing Systems Space Panel (GOSSP) to optimize input to the Members for their planning of validation (Recommendation C1).

The GOSSP should develop a scheme for identifying priorities for validation issues (Recommendation C2).

The following three recommendations are made to CEOS with respect to the development of the activities of its WGCV.

CEOS should consider enhancing the activities of the WGCV to address international co-ordination and collaboration of satellite product calibration and validation. For validation this should take into account priorities identified by the global observing systems (Recommendation C3).

On the basis of the priorities established above the WGCV should develop a pilot project to address issues such as measurement protocols, test regimes and data management in relation to calibration and validation (Recommendation C4).

CEOS members should maintain electronic bulletin boards providing access to up-to-date consensus calibration information for their sensors and CEOS members should provide access to them (Recommendation C5).

Data management

Effective data management is central to the success of the global observing systems. Recently the scope of the GCOS Data and Information Management Panel was broadened to include the interests of GOOS and GTOS. The need for a more integrated approach to this topic was recognized in a number of recommendations.

The Sponsors should continue to support inter-programme data management (Recommendation A7).

It is recommended that the global observing systems should seek a set of generic principles and/or guidelines governing the management of data, information and products of the global observing systems. These guidelines should not be restrictive but provide clarification and direction, based on the experiences of existing operational and experimental systems, that will facilitate the development, planning and integrated implementation of global observing system elements (Recommendation O3).

The Sponsor's policies should ensure full and open access of all data required for the global observing systems (Recommendation A8).

The importance of evolving new management concepts to expand the capability of the global observing systems was recognized.

In implementing their plans the global observing systems should take advantage of observations and products being derived through new regional and platform observing management activities such as the North American Atmospheric Observing System (NAOS) and Composite Observing System for the North Atlantic (COSNA) as ways of expanding global observing capabilities (Recommendation A5).

Particular problems were identified in the arena of terrestrial observations where for many observations data management systems are not well developed. Three specific recommendations concerning these types of observations were made.

For cryospheric observations it is recommended that coordinating mechanisms should be improved by focusing initially on two areas namely permafrost and glacier monitoring, that are already relatively well organized (Recommendation T4).

The Data and Information Management Panel (DIMP) and TOPC should develop an on-line meta-database providing details concerning the existing terrestrial networks currently collecting in situ terrestrial data of direct relevance to the prioritized requirements provided by the global observing systems (Recommendation T11).

DIMP in conjunction with TOPC should give high priority to developing an effective data policy and management plan appropriate to the specific problems of terrestrial data exchange that should then be actively tested through pilot projects. As part of this activity DIMP and TOPC should generate an assessment of the development of previous models of data systems for guidance in how terrestrial data could be shared, managed and distributed (Recommendation T10).

In developing improved capability for terrestrial systems especially for biospheric aspects it was regarded as essential to build on existing capabilities rather than create new systems.

In terms of an overall framework for providing international linkages it is recommended that the data and information management system for terrestrial observations work closely with the International Council of Scientific Unions (ICSU) World Data Centre System, International Geosphere-Biosphere Programme Data and Information System (IGBP-DIS) and with United Nations Environment ProgrammeÌs (UNEP) Global Resource Information Database (GRID) programme. After the initial data centres are established, it is expected that others will be added to the system (Recommendation T7).

Interactions between the global observing systems

The bringing together of representatives from the three global observing systems led to several recommendations concerning their responsibilities and how they should be interacting.

The Sponsors are urged to encourage a more rapid development of GTOS as an organization in terms of its secretariat and constituent panels, to bring it to a comparable stage of development to the other observing systems (Recommendation X7, see also recommendation T12).

The GCOS JSTC should consider taking the lead responsibility for the cryospheric and hydrologic component of climate but that the subject of climate impacts on terrestrial systems should be carried out jointly with GTOS (Recommendation A9).

It is recommended that an analysis be carried out by GTOS and GCOS working with the World Weather Watch (WWW ) to evaluate the extent of the overlap and possible linkages between the in situ ecological sites identified by GTOS and the base-line observation system defined by GCOS (Recommendation A11).

The philosophy, design and implementation of coastal zone measurements within GOOS should be coordinated with similar activities within the other global observing systems, particularly GTOS (Recommendation O6).

The global observing systems should work towards the implementation of a proposed regional pilot project aimed at demonstrating the utility of the global observing systems to developing countries (Recommendation T6).

The possibility of further joint scientific meetings between the global observing systems was discussed. The importance of 4-dimensional data assimilation methods and their impact on in situ and remote sensing observations was identified as a high priority.

It was recommended that an international meeting should be convened with the focus on data assimilation jointly sponsored by the three global observing systems (Recommendation X6).

Considerable discussion revolved around the role of the global observing systems in providing timely information for the assessment process of the Intergovernmental Panel on Climate Change (IPCC).

The Sponsors should consider a mechanism for the scientific advisory bodies to consult with the IPCC regarding data requirements for future assessments. The global observing systems should seek a multi-disciplinary response to the demands for observations and analysis from the IPCC assessment process, and to state-of-the-environment reporting processes (Recommendations X1, A2 and O4).

It was recommended to the global observing systems that they institute a short case study to examine the improvements in precipitation analyses to use as input for IPCC assessment (Recommendation X2).

Another area where it was recommended that the global observing systems should play a stronger role was in the area of indicators.

The scientific and technical bodies of the observing systems should, through their sponsoring agencies, enter into a dialogue with the bodies responsible for the development of the ÏindicatorsÓ strategy to make them aware of the valuable information resource that resides within the developing observing systems, and seek a mechanism for the continuing involvement and support of the observing systems for this strategy (Recommendation X3).

Common issues for the global observing systems

A joint meeting relating to the three observing systems not only led to identification of specific ways in which they should improve their interactions, but also led to recommendations about common approaches that they should adopt in carrying out their work. One set of principles arose from the "Guidelines and Principles for Climate Monitoring" developed as part of the GCOS Meeting on Long- Term Climate Change held at Asheville, North Carolina, USA in 1995 (Karl 1996). These are regarded as being not only critical for climate observations but also for others relating to long-term observations.

It is recommended that the Sponsors and scientific oversight committees of GCOS, GOOS and GTOS support the following principles and activities relating to the collection of long-term consistent observations (Recommendations A1 and X5).

- Studies must be carried out to assess impacts of the new technology as they affect the climate record preferably prior to implementation. The sensitivity of objectives, applications and products to the change should be determined. This information should be widely distributed;

- Periodic information on data quality monitoring and data assessment including random errors and long-term systematic biases from the appropriate monitoring center must be assembled;

- Routine and permanent mechanisms for evaluating and monitoring observing system performance should be put in place;

- There must be wide and regular distribution of periodic information regarding calibration and metadata and processing of data;

- Baseline reference networks should be established similar to those established for surface and upper air within the WWW for GCOS to ensure the collection of long-term consistent records to reliably characterize the state of the Earth system. Emphasis should be initially based on defining the minimal configurations necessary for this task;

- In implementing these principles and activities every effort should be made to build on existing mechanisms, plans and systems as appropriate.

- Associated with the principles and activities outlined in the previous recommendation is the continuing role of the global observing systems in ensuring that observing systems evolve on the basis of carefully conducted scientific analyses involving the broader scientific community.

The scientific and steering advisory groups of the global observing systems should continue to conduct scientific evaluation through impact and sensitivity studies so as to influence the design and evolution of the observing systems in cooperation with existing scientific committees (Recommendation A6).

Associated with the need to ensure long-term systematic collection of observations it was concluded that there should be a clearly understood uniform integrated approach for distinguishing the experimental research systems from systematic operational ones allowing for differences in implementation between different types of observations.

The global observing systems should seek a common methodology for drawing the distinction between experimental and ad hoc observations on the one hand, and systematic, routine global observing system observations on the other (Recommendation O1).

Preparatory materials for the meeting indicated the enormous range of in situ observations currently being collected, whose enhancement is required by various components of the global observing systems. This highlighted the need to develop an accepted procedure for prioritization.

The global observing systems should recognize the fundamental importance of prioritization for the development of operational, long-term observing systems and should encourage the development of common approaches to prioritization (Recommendation O2).

It was agreed the following steps could be included in a common prioritization process (based on Recommendations O2 and X4; also see Recommendations T8 and T9).

- Articulate the objectives or clusters of objectives in relation to the phenomena whose understanding has to be improved as a result of the work of the global observing systems;

- Explicitly identify the products and benefits attached to the component of the observing system under consideration;

- Examine feasibility, difficulty, and practicality of implementing elements;

- Discuss the relevance and impact of the element with respect to the objectives and cost;

- As appropriate, apply a hierarchical sampling framework.

There was discussion about the development of integrated global observation strategies and how in situ observations might relate to these. Presentations were made outlining various proposals that have been made by a number of individual national organizations and by CEOS. As a result of these discussions the following recommendation was made:

It is recommended to the scientific advisory bodies of the global observing systems (GCOS, GOOS, and GTOS) that they continue to explore prospects for involvement in the continuing discussions on the development of integrated strategies for global observations. In particular it is recommended to the scientific advisory bodies (Recommendation X7):

- That representatives of the global observing systems engage with CEOS in better defining their roles as affiliates, especially with respect to calibration and validation, associated with the evolving emphases of CEOS activities;

- That the work of the global observing systems contribute to an improved understanding of the roles of in situ and remote sensing observations through a more explicit emphasis on their requirements based on an end-to-end view of key products, which have been generated;

- That the results of this meeting be reported at the CEOS plenary in Canberra, Australia, by the chair of the JSTC of GCOS.

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