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8 Documenting Global Change OVERVIEW Two aspects of the U.S. Global Change Research Program will play a particularly crucial role in the success of all aspects of the program: (1) monitoring of the earth system over years to decades in order to document the global changes and (2) information management to make such docu- mentation feasible and to provide information for the various process stud- ies and modeling efforts described in chapters 2 through 7 of this report. An integral part of developing a monitoring and information manage- ment strategy is the iden~ciD~cabon of how the needed tasks will be accomplished, particularly in the case of satellite observations, where the expense and lead time require extraordinary care in scientific justification and realistic plan- ning. Key missions in this regard include the ongoing NOAA polar orbiting and geostationary satellites, the Deparunent of Defense GEOSAT and ongoing Defense Meteorological Satellite Program (DMSP) series, the Earth Obser- vation Satellite (EOSAT) Landsat series, approved NASA missions, such as the Upper Atmosphere Research Satellite (WARS) and TOPEX/POSEIDON (the U.S.-French ocean topography experiment), and two planned NASA series that are part of Mission to Planet Earth, ache Earth Probes and the Earth Observing System (EOS). In addition, a number of other missions are operated by other nations, including the Soviet Union, Japan, France, and This chapter was prepared for the Committee on Global Change by S. Ichtiaque Rasool, Jet Propulsion Laboratory; D. James Baker, Jr., Joint Oceanographic Institutions; and Ferris Webster, University of Delaware; with input from Francis P. Bretherton, University of Wisconsin. 215

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216 RESEARCH STRATEGIES FOR THE USGCRP the European Space Agency (ESA). Japan and ESA are partners with NASA in EOS, which will begin to operate in the late 1990s. EOS is an integrated observation and information system with the potential to provide a new generation of capability for understanding and monitoring the earth system. For the purposes of this chapter, monitoring is defined as the minimal subset of currently achievable sustained global measurements, including their processing to deliverable products, that will document the baseline state of the planet earth and global changes. Information management, which is an extension of data management, is defined as including a com- prehensive process of compilation, distribution, and preservation of basic data, derived products, and information about them and is approached in terms of the inputs to and outputs from a variety of scientific activities within global change research. MEASUREMENT STRATEGY Monitoring Requirements Public and scientific concern with global change centers on, but is not confined to, significant changes in the earth's climate in the decades to come, due to increases in atmospheric carbon dioxide concentrations prima- rily from the increasing worldwide consumption of fossil fuel and to the emission into the atmosphere of other greenhouse gases such as methane, nitrous oxide, and chlorofluorocarbons. The stratospheric ozone layer is also a focus of attention. Other impacts of human activities, such as acid rain, deforestation, and soil degradation, are affecting the global environment in ways that we are only beginning to comprehend and yet surely include interaction with climate and the stratosphere. A significant element in these concerns is the realization that by the time the serious threats to humanity posed by these changes become obvious the changes may be irreversible, at least for several centuries. Furthermore, the driving forces are so deep- seated in our industrialized society and growing world population that mecha- nisms to control them will be difficult to put in place. Finally, our understanding of the earth system processes is quite inadequate for effective management on the scale that will be required. The focus here is on the initial scientific design of a monitoring system with an emphasis on those aspects that are already under way or could be implemented in the near future, at least in prototype form. Because of the very nature of the long-term commitment required for monitoring, special institutional and funding arrangements are necessary, major resources are involved, and great selectivity is required. Therefore, for each variable, consideration is given to the following questions: Which measurements are both critical to the integrity of the program and feasible for immediate implementation on a long-term basis within the

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DOCUMENTING GLOBAL CHANGE 217 context of existing capabilities and the research programs and process stud- ies currently being planned? What is the current status of the monitoring system and what needs to be done to ensure consistency and continuity? . Two kinds of global-scale long-term monitoring are needed: (1) moni- tonng of the magnitude of the driving forces that may bring long-term changes in the equilibrium state of the earth system and (2) monitoring of the state variables or the "vital signs" of the earth where such changes are liable to manifest. A comprehensive approach leads to a long list of global measurements that need to be made on an ongoing basis (e.g., Earth System Sciences Committee, 1988, Table 9.1A). In the context of the overall program, relative priorities for individual variables must be judged not only in terms of their contribution to the monitoring requirements but also in view of their importance for validating models and advancing our understanding of specific processes, the magnitude of the effort required, and the state of readiness of the observation and analysis techniques involved. Table 8.1 is an attempt to identify priority requirements and comment on the current status of each. In many cases, new approaches are being devel- oped. It is clear that the measurement system will evolve with time. Global Synthesis In chapter 2, a new framework for earth system modeling is proposed. In order to eventually realize fully coupled, dynamical models of the earth system, a step-by-step approach is required to develop several partial mod- els representing the interface between the terrestrial biosphere and the at- mosphere, the coupling of physics and chemistry within the atmosphere, and the interface between the oceans and the atmosphere, including the chemical exchange and the biological dynamics within the upper layers of the oceans. In order to build these models, we will need time-dependent data sets, often global in extent, which will be used as input to these models and also to test the predictions of these models. These data will be derived by indirect or surrogate global-scale measurements, together with regional- and local-scale process studies, to infer global-scale values of the desired vari- able. The need for such data sets, specific for global change studies and the development of realistic earth system models, puts new and stringent re- quirements on the global observing system. These requirements are simul- taneous observation from satellites of several parameters covering large areas over long time periods, subsatellite area coverage and field measurements, global surface observation networks on the land and in the oceans, and subsurface measurements.

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218 TABLE 8.1 Earth System Monitonng RESEARCH STRATEGIES FOR THE USGCRP Parameter Status and Commentsa Driving Forces for Global Change Solar irradiance Solar ultraviolet spectrum Volcanic aerosols Trace gases Carbon dioxide Methane, nitrous oxide, carbon monoxide Chloro fluoro c arbons Biomass emission rates of trace gases Land use change Global Change Symptoms (Vital SignsJ Global tropospheric temperature Surface temperature Total ozone Stratospheric temperature Ongoing; need intersatellite calibration Ongoing from SBUV/Nimbus, UARS (1992 and beyond); need check on long-term consistency Ongoing (SAGE) for polar stratosphere, ad hoc measurements from surface observatories; need global monitoring program Good coverage in time and space from surface network, NOAA/GMCC Ongoing from BAPMON and ad hoc coverage, field experiments (e.g., ABLE); need reliability, IGAC program should resolve deficiencies Ongoing from industry statistics, polar ozone expedition Very poor, spotty coverage; ad hoc measurements, NOAAIAVHRR and field experiments may provide global estimates Poor; IGBP initiative (See Report No. 8), NOAA/AVHRR with Landsat and SPOT, EOS/MODIS, HIRIS provide potential measurements Ongoing from radiosondes, NOAAJ TOYS; long-term consistency in coverage and sensor stability and intersatellite consistency are the major Issues Ongoing from surface meteorological network, satellites for sea surface temperature; issues related to spotty coverage in the southern hemisphere, land and ocean integrated data analysis need to be resolved Ongoing from Dobson and satellites; need to pay attention to potential gaps in coverage by TOMS Ongoing from radiosondes, Nimbus, NOAA, WARS, EOS TABLE 8.1 continues

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DOCUMENTING GLOBAL CHAlIGE TABLE 8.1 (continued) 219 Parameter Status and Commentsa Upper troposphere water vapor Clouds Interannual air-sea interaction fluctuation (El Nino) Oceanic and atmospheric heat transport and storage Oceanic carbon dioxide uptake Sea ice extent Rainfall Sea level Biospheric parameters/land and oceans Soils Ongoing from WWW, GOES, Meteosat and planned for HIRIS/EOS; long- term trends not yet discernible Ongoing from ISCCP data, earth radiation budget, field experiments (FIRE) Ongoing from TOGA data sets; intensive research activity ongoing Ongoing and planned from WOCE, JGOFS, NOAAtAVHRR, TOPEX/ POSEIDON, ERS 1 FISCAL, EOS; research ongoing Ongoing and planned from JGOFS (1989-1996), Nimbus, SEAWIFS, ADEOS, EOS/MODIS Ongoing and planned from Nimbus, DMSP, SSM/I, ERS 1, EOS, lERS 1, Radarsat Poor; WCRP Global Precipitation Climatology Project, GEWEX, TRMM, EOS, BEST provide potential measurements Ongoing from global network of in situ gauges, satellite altimetry, VLBI Spotty, poor; measurements from JGOFS, Nimbus 7, NOAA/AVHRR, SPOT, Landsat, Radarsat, ADEOS, EOS, JERS; surface measurements from UN/hIAB, NSF/LTER, USES/ CFI Very poor; need coordinated surface observation networks, potential expansion of SOTER data base, EOS/ SAR aAcronyms and abbreviations used in this table are as follows: ABLE ADEOS AVHRR BAPMON BEST CFI Atmosphere Boundary Layer Experiment Advanced Earth Observing Satellite Advanced Very High Resolution Radiometer Background Air Pollution Monitoring Network Bilan Energetique de la Systeme Tropical Continuous Forest Inventory TABLE B.1 continues

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220 TABLE 8.1 (continued) RESEARCH STRATEGIES FOR THE USGCRP DMSP Defense Meteorological Satellite Program EOS Earth Observing System ERS 1 European Space Agency's remote sensing satellite FIRE First ISCCP Regional Experiment GEWEX Global Energy and Water Cycle Experiment GMCC Global Monitoring for Climate Change GOES Geostationary Operational Environmental Satellite HIRIS High-Resolution Imaging Spectrometer IGAC International Global Atmospheric Chemistry Program IGBP International Geosphere-Biosphere Program ISCCP International Satellite Cloud Climatology Project JERS 1 Japanese Earth Resources Satellite JGOFS Joint Global Ocean Flux Study LTER Long Term Ecological Research MAB Man and the Biosphere MODIS Moderate Resolution Imaging Spectrometer NOAA National Oceanic and Atmospheric Administration NSCA11 NASA Scatterometer on ASEOS NSF National Science Foundation SAGE Stratospheric Aerosol and Gas Experiment SAR Synthetic aperture radar SBUV Solar Backscatter Ultraviolet SEAWIFS Sea-viewing, Wide Field-of-View Sensor SOTER Soil Terrain Digital Data Base at Scale Elm SPOT Systeme Probatoire de ['Observation de la Terre SSM/T Special Sensor Microwave/Imager TOGA Tropical Oceans and Global Atmosphere Program TOMS Total Ozone Mapping Spectrometer TOPEX/POSEIDON U.S.-French Ocean Topography Experiment TOVS TIROS Operational Vertical Sounder TRMM Tropical Rainfall Measuring Mission UARS Upper Atmosphere Research Satellite UN United Nations USFS U.S. Forest Service VLBI Very Long Baseline ~terferometry WCRP World Climate Research Program WOCE World Ocean Circulation Experiment WWW World Weather Watch

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DOCUMENTING GLOBAL CHANGE TABLE 8.2 Examples of Globally Synthesized Products Derived from Earth System Measurements 221 Product Derived from Latent heat flux Global surface air temperature Vegetation type, plant stress Ocean chlorophyll Oceanic uptake of carbon dioxide Oceanic and atmospheric transport Trace gas emission from biomass burning Radiation balance, temperature, moisture, field studies Surface radiating temperature Land cover change, greenness index Ocean color Ocean temperature, surface wind, ocean color, atmospheric carbon dioxide Wind, temperature (ocean alla heat atmosphere), ocean currents Fire frequency and intensity, regional mace gas concentrations From an observing system consisting of the elements above, we can begin to derive globally synthesized products such as those in Table 8.2. In addition to new data that will need to be collected and synthesized on a global scale, existing data could provide useful information if made acces- sible to the research community. Data sets classified for military intelligence purposes, such as the global data set on digital terrain information impor- tant for many aspects of global change research ranging from surface en- ergy interactions to surface roughness fields for circulation models, could provide valuable information if released. Process Studies Chapters 3 through 7 of this report identify the observation needs that must be given priority to make progress in each field of research. It is clear that the pace of activities in each of these areas is largely limited by the available data. This section summarizes data needs by providing examples for each chapter to provide an understanding of the scope of the observation and monitoring program required to implement a research program. Earth System History and Modeling The geologic record is the only source of information on how the climate system has evolved through time, and in chapter 3 the specific important geoscience contributions to global change research are enumerated, along with the observational needs for sustaining research in this area. A global data base of paleoclimate observations is needed and will draw on a great

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222 RESEARCH STRATEGIES FOR THE USGCRP diversity of paleoenvironmental sensors, including direct observations, his- torical documents, anthropological records, tree rings, ice cores, lake and ocean sediments, and corals. Measurements are also needed to quantify observed environmental changes in terms of temperature and precipitation. For example, because they have great significance for human activities such as food production, additional high-resolution marine records are critically needed to support regional pro- cess studies. Multiple independent monitors of changes in temperature, precipitation, biota on land, dust and sulfate aerosols in the atmosphere, and atmospheric concentrations of carbon dioxide and methane are also needed. More measurements of sea surface temperature, deep and intermediate waters, aeolian fluxes, and components of the carbon cycle are also needed. Fractionation of isotopes in precipitation, plankton, and tree rings; en- trapment of gases within ice; and incorporation of trace metals into corals are the types of process studies of modern environments that would advance our knowledge of global change. Human Sources of Global Change Chapter 4 formulates a research plan for achieving a better understanding of the human sources of global change. The process studies necessary to accomplish this goal will need measurements of the amounts of energy and materials being used per unit value of production, population density, eco- nomic activity, and land tenure pattern. Data collection in this area has both a historical and a current compo- nent. It includes data on human activities that lead to changes in the chemical flow, physical properties, and surface covers of interest as well as data on demographic, technical, and socioeconomic variables. Collection of these types of data is complicated by the fact that many of the coefficients for industrial processes, such as carbon dioxide emission coefficients for various energy technologies, are well documented, whereas coefficients for land use processes, such as methane from various rice culti- vation techniques, are not. Better data collection strategies need to be developed, especially in the area of global land cover change and its impact on global climate. Water-Energy-Vegetation Interactions There have been few successful efforts, either in modeling or in data acquisition, to link the activities addressing the physical climate with those addressing the terrestrial biosphere so as to further understand and improve our capability to predict global change. Chapter 5 focuses on the interactions between the vegetated land surface

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DOCUMENTING GLOBAL CHANGE 223 and the atmosphere, particularly on the exchanges of energy, heat, and carbon dioxide between the two. This goal requires development of com- prehensive biophysically based models of the atmosphere and land bio- sphere that will utilize measurable parameters. Table 5.3 identifies the ongoing field campaigns currently providing the regional data measurements and lists the campaigns being planned to extend the data collection process to meet the research requirements. The param- eters of interest being sought by these campaigns are referenced in the tables. Terrestrial Trace Gas and Nutrient Fluxes Although the importance of photosynthesis and respiration in controlling carbon dioxide and oxygen has long been known, the biospheric processes controlling nitrogenous compounds such as nitrous oxide, nitric oxide, and ammonia, sulfur compounds such as hydrogen sulfide, and various hydro- carbons have only recently been appreciated. Chapter 6 investigates this recent development and places it in the con- text of our current environment, where, for the first time in the history of the earth, these natural and human-caused atmospheric and biospheric pro- cesses may alter the global climate with potential impacts on human welfare. The data needs of this research are associated with process studies that relate methane production, consumption, and flux to environmental param- eters such as burning and livestock farming and to changes in ecosystem structure and function. The dynamics of collecting these data must empha- size the integration of information obtained at different scales from simulta- neous chamber, tower, and aircraft flux measurements. Also, better spatial and temporal coverage of atmospheric methane concentrations and isotopic composition (carbon and hydrogen) in source regions must be obtained. Field tests and models also need to be developed relating fluxes of water, sediment, nutrients, and pollutants to interactive fluxes of trace gases be- tween the biosphere and the atmosphere. Table 6.1 summarizes the environmental variables regulating the fluxes of trace gases from terrestrial ecosystems, giving a flavor of the complexity of the observational requirements of this research. Biogeochemical Dynamics in the Ocean Chapter 7 identifies the efforts, including those currently under way, required to develop the capability to predict the effect of projected climatic change on the ocean's physical, chemical, and biogeochemical processes, especially as they feed back to climate via the release and absorption of radiatively important gases. The chapter gives the status of ongoing and

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224 RESEARCH STRATEGIES FOR THE USGCRP proposed programs that focus on five areas of investigation and their atten- dant data measurement needs: (1) biogeochemical flux with emphasis on carbon; (2) ocean-atmosphere interface; (3) oceanic ecosystem response to climatic change; (4) underlying physical processes in the oceans and atmo- sphere; and (5) processes in the polar regions. The data needs are global and long term and will involve satellites, surface buoys, and subsurface sounding to assess a range of parameters, including sea surface temperature, radiation balance state, winds, chlorophyll, atmospheric carbon dioxide, oceanic carbon dioxide, subsurface dynamics, and ocean topography. Together these data will be used to estimate fluxes of energy and trace gas at the ocean- atmosphere interface. Existing and Planned Observing Systems In order to meet the data requirements for documenting global change, for developing and testing models at the interfaces of land, oceans, and atmosphere, and for undertaking continental-scale process studies, a mea- surement program that has the following elements is needed: a satellite system for measuring a number of parameters, often simul- taneously, with a time scale ranging from seconds to decades and a space scale ranging from pixels to global; large-scale field and process studies involving satellites, aircraft, bal- loon, and surface observing stations; a global observing network on the earth's surface for measuring those variables that cannot be observed from space and for validating and calibrating the remotely sensed measurement; and two modeling activities, one to help decide the optimal design of the monitoring system and the second to derive data products from indirect and surrogate measurements. Space Observing System The science requirements are developed in the preceding chapters in a context of ever-improving techniques for global observations, many of which are dependent on satellites for the global, synoptic, and long-term view. The current international operational satellite system meets some of the science requirements, but it is clear that it could be upgraded and expanded with existing technology to produce many of the long-term data that will be needed for a program to study global change. In order to upgrade the system, it will be necessary to use the technology that has been developed on specialized research missions, to carry out data validation experiments and to establish new comprehensive data archives

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DOCUMENTING GLOBAL CHANGE 225 and data dissemination systems. Such an upgrade is indeed feasible if the proper support is provided. Therefore the current satellite system, aug- mented with technology developed by research missions and supported by validation experiments and a comprehensive data system, could provide the basis for a global change observing system. In order to actually develop the current system into a system for the study of global change, a certain class of actions needs to be taken immedi- ately. These include validation of current data sets, transfer of demonstrated new technology to operations, identification and filling of gaps in the system, and finally developing a "total" system, such as EOS, that will carry out the space observation program for the next several decades. To establish the necessary parts of the global change observing system, we need to look first at existing activities. Current NOAA, ESA, Japanese, and Indian operational satellites produce routine data products on a number of parameters important to global change. These include cloud cover, sea surface temperature, atmospheric temperature profiles, vegetation index, and ice cover. The study of global change requires that these measurements be continued and at the same time adequately validated. The World Climate Research Program (WCRP) has started to produce long-term validated data sets for climate purposes, including cloud climatology, sea surface tempera- ture, radiation budget, precipitation, surface winds, and ocean currents. At the same time, the International Satellite Land Surface Climatology Program (ISLSCP) is planning to produce validated data sets on surface albedo, land surface temperature, vegetation cover, and evaporation and transpiration. It is therefore important that the necessary support be provided to com- plete the validation experiments of existing programs and to provide for the selection of appropriate algorithms to produce routinely the data sets crucial to studies of global change. A number of research missions flown during the past decade have shown that it is feasible to measure these critical parameters on a global scale. The Nimbus series, Seasat, the Geostationary Operational Environmental Satellite (GOES), and Shuttle-based tests of in- struments have provided valuable information on how to measure properties of the earth ranging from the radiation budget to ocean primary productivity. Perhaps the best example of using satellite measurements for constructing large-scale data bases is found in the approval and initial stages of the implementation of ESA's remote sensing satellite, ERS-1. This satellite system is the first of an operational series of satellites aimed at an integrated set of measurements of the ocean, land, and atmosphere. The ERS-1 design includes a full validation program and a data system, making it potentially a good model for larger systems aimed at studying global change. Other examples include NASA's Upper Atmosphere Research Satellite (UARS), which is designed to study the chemistry, radiation, and dynamics of the stratosphere; the joint U.S.-French TOPEX/POSEIDON precision al

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230 NOM-9 it: c, ~ - ''em ~ - I ~ ~l I ~_ \\ I ~ ~ ~- I ~'! /) I - :~ RESEARCH STRATEGIES FOR THE USGCRP FIFE 15:17 June 4th, 1987 NASA C-130 _ ~ LEGEND Wind Vector Road Et Automatic Meteorological Station Bowen Radio Flux Measurement X Eddy Correlation Flux Measurement NASA H-1 N ~ (if) I ~ -_J 1 NCAR King Air :7 - 15 km T FIGURE 8.2 Situation at the FIFE site at 1517, June 4, 1987; ume of the NOAA-9. (1) Surface flux stations arid automatic meteorological stations monitor surface fluxes and near-surface meteorological conditions. (2) NOAA-9 satellite scans Me site at 1-lan resolution. (3) NASA C-130 traverses the site at 5000-m above ground level, taking scarmer and sun photometer data. (4) NASA helicopter hovers above preselected site at 250-m above ground level and acquires radiometric data. (5) NCAR King Air collects eddy correlation data at 160-m above ground level. (Source: NASA, 1988.) Surface Observation Networks Several surface observation networks have been established around the globe to monitor the baseline characteristics of the surface and the atmo- sphere. In this regard, the networks organized by the World Meteorological Organization (WMO) and the U.N. Environment Programme CHEEP) are noteworthy. At the same time, the WCRP has initiated studies to validate and assess the accuracy of the data base, and the Global Monitoring for Climate Change (GMCC) of NOAA produces occasional updates of the global climate trends based on data from these networks. Noteworthy for the USGCRP studies is the Background Air Pollution Monitoring Network (BAPMON), which was established in 1970 as one of the WMO's early activities in the field of air pollution. It has since become an important component of the Global Environment Monitoring System (GEMS).

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DOCUMENTING GLOBAL CHANGE 231 The function of BAPMON as outlined by the WMO Executive Council Panel of Experts in 1982 is "to obtain measurements on a global and re- gional basis of background concentrations of atmospheric constituents which may affect environmental pollution or climate." From the variability in time and space and the possible long-term changes reflected in these data, it will be possible to assess the influence of human and natural occurrences on the composition of the atmosphere. Such information is required to study the effects of atmospheric composition on climate, and to predict future climatic change due to future human activities; to aid in the study of the mechanisms of long-range atmospheric transport and deposition of potentially harmful substances; and . to aid in the study of the biogeochemical cycles of important constitu- ents in order to establish a sound basis for assessing human impacts on these cycles and for making predictions of possible impacts on the environ- ment. At the end of 1990, some 94 countries were participating in the BAPMON program, with 216 stations either providing data (166), in preparation (12), or in planning (38~. Stations are categorized as global (16), continental (10), or regional (190~. Global background air pollution stations document long-term changes in atmospheric composition likely to affect the weather and the climate. These stations are located in areas where no changes in land use are anticipated for at least 50 years within 100 km in all directions from each station. Although the concept of BAPMON is basically sound, measurements made by different groups within the network need to be intercompared and standardized on an ongoing basis. All relevant data and information on procedures should be deposited and maintained in a permanent archive that is accessible. Careful attention needs to be paid to the validation of the atmospheric transport model, particularly in relation to vertical mixing and interhemispheric exchange. Inert Racers of known source strength such as chlorofluorocarbons, and existing satellite measurements of atmospheric water vapor and tropical winds may be useful here. Isotopes should be measured throughout the network as soon as competent staff can be trained and ad- equate facilities made available. The vertical profile of the seasonal cycle and year-to-year variations of carbon dioxide should be measured at more latitudes. Networks also exist to monitor and conduct process studies on ecological characteristics of sites around the world, e.g., the biosphere reserves under I3NESCO's Man and the Biosphere program. These and other sites, for example, sites within the United States such as the Long-Term Ecological Research (LTER) sites funded by the National Science Foundation and other ecological monitoring and research sites funded by other agencies, could provide ecological information relevant to global change (LTER Network

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232 RESEARCH STRATEGIES FOR THE USGCRP Office, 1989~. In addition, the IGBP Global Change Regional Research Centers will coordinate existing networks and develop new ones in less developed countries (IGBP, 1990~. The committee recommends that the plans for the establishment of IGBP Regional Research Centers be imple- mented as soon as possible. International Coordination The international community is focusing increased attention on climate and global change research, potential impacts, and response strategies. Co- operation among agencies engaged in space-based, global earth observation programs is already extensive and is pursued not only through bilateral collaboration but also multilaterally by international satellite coordination groups. Such groups coordinate multilateral missions (including the pay- loads of the U.S., European, and Japanese polar platforms), promote compatibility among observation systems, facilitate data exchange, and set data product standards-all of which benefit the global change user community. One such group, the Committee on Earth Observations Satellites (CEOS), created as a result of the 1982 Group of Seven Economic Summit, is the appropriate focal point for international coordination of the space segment of global change earth observations. Its members are those government agencies with funding and program responsibilities for satellite observa- tions and data management. Current members are NASA, NOAA, ESA, the European Meteorological Satellite Organization (EUMETSAT), and coun- terpart space and earth observation agencies in Japan, Canada, France, the U.K., Germany, Italy, India, Brazil, and Australia. NASA and NOAA are proposing changes intended to strengthen CEOS interaction with both international scientific programs (ICSU's IGBP and the WCRP) and intergovernmental user organizations (the Intergovernmental Panel on Climate Change (IPCC), WMO, UNEP, and the Intergovernmental Oceanographic Commission (IOC)) with the specific goal of focusing the earth observation mission planning in space agencies on global change re- quirements. Scientific and intergovernmental agency representatives would be invited to participate in CEOS policy deliberations and technical coordi- nation activities. The U.S. agencies are further proposing revitalization of the CEOS Sensor Calibration and Performance Validation Working Group to undertake important global change calibration activities, as well as the possible chartering of a Working Group on Space Networks. The CEOS Working Group on Data, chaired by NOAA, already plays an active role in standardizing data formats worldwide, achieving an international interoperable catalog system, and identifying data sets to test a proposed international network for electronic data transmission.

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DOCUMENTING GLOBAL CHANGE INFORMATION AND DATA MANAGEMENT 233 A data and information system for global change research must foster the process to identify global change and to evaluate its impact on human ac- tivities in order to set a course of action to mitigate harmful effects. Conse- quently, the USGCRP will make unprecedented demands for the assembly and dissemination of large volumes of diverse and interdisciplinary data and information. Data System Requirements Data system requirements for global change fall into five categories of activity: 1. Collection, processing, and analysis of past and existing global mea- surements to establish the relative mean state of the earth system, obtain measures of system variability, detect change, and understand large-scale interactive processes. 2. Sustained (future) global measurements to monitor and document change and to supply essential state variables for earth system models. 3. Process studies to understand particular phenomena and relate smaller- scale processes with the large-scale variables of the global system. 4. Analysis of past records, both instrumental and proxy, to obtain long-term reference states of the global system, document and understand secular fluctuations in the earth system and their relationship to shorter-time-scale processes, and provide a basis for testing models. 5. Production of data fields (with known or uniform requirements) from assimilation and/or simulation models. Measurements acquired on regional and worldwide scales must be merged with other, often dissimilar, data to produce analyses and products. Subsets of these data must be quality assured, documented, distributed, and archived. Contemporary and future researchers must be able to acquire and use these data in their analyses of global change phenomena. The efficient acquisition, quality assurance, documentation, distribution, and preservation of relevant data sets of all types is crucial to the success of the USGCRP. The section "Information and Data Management" was prepared following the out- line of recommendations made by the NRC Committee on Geophysical Research (1990~.

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234 RESEARCH STRATEGIES FOR THE USGCRP Kinds of Data Needed Data needed for broad global change research run the gamut from site- specific to truly global data sets, as described earlier in this chapter. Disci- plines involved include the geosciences, ecology, biology, and socioeconomics. Many data sets will cross disciplines, and people of diverse talents and skills will be required to assemble them. Time series data of all types are prominent in global change research to detect past and present trends. Proxy data are necessary when direct measurements are impossible. The need for accuracy is important, as some of the predicted changes will be small and take place over long periods of time. Often data sets will be enormous, owing to the resolution and spatial scale needed to address global issues. Functions of a Data and Information System The prime function of a data and information management system is the stewardship of the data and information, with all its ramifications. Such information is costly to acquire. Its safekeeping must not be left to chance. Other functions may vary depending on programmatic goals, attributes of the thematic data or programmatic issues, and researcher needs. These func- tions include, but may not be limited to, the following: Data preservation to ensure the long-term stewardship of research data. Data distribution. Data must be easily accessible by the world research community with as few restrictions (including cost) as possible. Data integration and product production. The system must be able to integrate data within and across disciplines to create data products for use by the research community and policymakers. Data quality assurance using high standards to maximize the applica- tion of data to answer global change questions. Provision of data documentation. Data sets must be fully documented (documentation is often termed "metadata") to ensure their complete under- standing today and their usability in the future. Data identification and acquisition. The system must take an active role with scientists to identify data sets useful for global change research. Provision of a programmatic focus for data management in order to focus the flow of information necessary to conduct global change research. Selective data retrieval. It must be possible to retrieve selectively data relevant to a user's needs. Standardization of procedures to ensure that standards for quality assurance, documentation, and distribution are similar among system components. Many requests to the data management system will be for derived prod- ucts such as analyses or edited data collections in association with descrip

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DOCUMENTING GLOBAL CHANGE 235 live text or graphical material, rather than raw observational data. Thus the system must provide information as well as data. It must keep the raw data as well, to provide the material for future reanalyses. It must play an active role in the generation, acquisition, quality control, dissemination, and reten- tion of value-added products. Creating a New System A new system for data and information management should begin with the establishment of objectives. What data sets are needed to describe global change? What are the highest priorities? Setting those objectives and priorities is an activity that goes beyond data management. The funda- mental scientific design of the USGCRP should include setting objectives for the data and information that will be needed. These objectives must be set with a data management input into the scientific process. A network of discipline-oriented data centers is an important and neces- sary component of the system to support global change research. Data cen- ters should be created for those disciplines important to global change re- search that are not included in the network of national data centers. The network can be augmented by establishing new centers or by expanding the purview and resources of existing centers. The extraordinary information requirements that the global change pro- gram will make on existing data management elements will necessitate aug- menting the existing system with a new mechanism to handle these data. This mechanism is a data management infrastructure. One does exist today, but it is incomplete, inadequate, and poorly supported. It must be strengthened. If the USGCRP is to be a success, a strong data management system must exist to support it. The new system should build upon itself. As a first step, we must make sure that the existing components work. Making them work is not a techni- cal challenge but one of will and resources. Existing U.S. environmental data management units must be improved, restructured, or replaced. Then we can move on to create the more complex system. New components must be created. Some existing institutions can serve as models. Above all, data and information management must be adequately supported. Agencies must shoulder the responsibility of providing for the steward- ship of the data they generate. Data management should be considered at the outset of every project, explicitly defined, and adequately budgeted for the life of the project. Arrangements should be made for the long-term archiving of the data. A new system should demonstrate success through practical prototypes. Confidence will be built by proving accuracy, by showing that things can be

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236 RESEARCH STRATEGIES FOR THE USGCRP done right, and by producing some early products of value. This can be done by beginning feasible pilot projects of great importance. The Master Directory project sponsored by the Interagency Working Group on Data Management for Global Change is an excellent example. This project is creating a high-level directory of data sets related to global change held by many agencies and institutions. Its success depends on common infor- mation standards among centers and on operational computer network links. Scientific Involvement If we look at existing data and information management activities, we find that successful data systems and centers often combine data manage- ment with scientific use. Successful data centers not only work with scientists but also have their active support. Users support the development of the data system and provide feedback. A successful system must involve the scientific user community at all stages of development and operation. Without that support and involvement, the data system is unlikely to meet the needs of the program (Data Management and Computation Committee, 1982~. Achieving effective scientific involvement will not be easy. Unfortu- nately, much of the scientific community is not aware of the need to be involved in any unified global change data and information management approach. This attitude is part of a pattern: data management has long been considered a secondary aspect of research. Since data will be such a critical element in global change research, a change of attitude is essential. Fortunately, there are many signs that this change is taking place, both in research scientists and in sponsoring agencies. For example, an elaborate system is being devised to handle the data that will be generated by NASA's EOS program. The EOS Data and Information System (EOSDIS) is being planned in parallel with the EOS program in an attempt to ensure that the scientists will be involved in the storage and archiving of data as well as the analysis. Active researchers must be participants in the process. They should define needs and create the framework for a data and information system to meet those needs. They should help establish procedures and data centers. It will not be enough for them simply to assent to what a group of data technologists are creating. There must be incentives for researchers to be involved. The system must respond to scientists' needs. It must be perceived as the optimal way to do research with data. A simple feedback process will have a beneficial effect. When advice is sought and listened to, there is an incentive for involvement. Not only should incentives be created, but existing disincentives should be removed. User fees above a minimal cost for reproduction for scientific

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DOCUMENTING GLOBAL CHANGE 237 use of data constitute an existing disincentive. The nature of global prob- lems requires access to large data sets. If their costs make this prohibitive, then exploratory research will be obstructed. For example, Landsat data are currently so expensive that the data are generally beyond the reach of the research community. The global change data system should have the lowest possible user fee structure. Data should be free wherever possible. Data Directories Many scientists face major obstacles in finding out what pertinent data are available; in some situations, obtaining the data may be a practical impossibility. In other cases, inadequate documentation makes personal contact with the primary user imperative. There is a need for all centers holding data acquired through federal funding to provide well-documented information about the extent of their holdings and the accessibility of the data. Furthermore, data interchange among agencies will become a major issue as global change programs re- quire data from ever-wider sources. The lack of interoperability among data directories is a serious deficiency of the current system. It must be addressed if the USGCRP is to draw upon existing and future data holdings. Locating data, both nationally and internationally, will be helped by the establishment of a centralized data directory. This directory will have in- formation about information. It will be created by a joint effort of the national data centers and, eventually, international data sources. The data directory should be electronically accessible and user friendly. It should provide as much information about data sets as possible, including location, access policies and procedures, and information about the data's complete- ness, accuracy, general usefulness, documentation, and limitations. It should be free to use. Data Submission There are valuable data sets that remain in the custody of individual research groups or even individual investigators, with the consequent ac- ceptance by them of the data-handling task. Some of these data sets are widely known and accessible; others are not. There are many reasons for the failure of individual scientists to provide data to the data centers. Among these are a desire for exclusive access to data, the reluctance to divert time and effort away from research in order to clean up a messy research data set, and lack of awareness of the existence of appropriate repositories or of the importance of depositing data in such centers. In general, the research community is not sufficiently aware of the im- portance of ensuring the availability of environmental data. Until this changes,

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238 RESEARCH STRATEGIES FOR THE USGCRP potentially valuable data sets will continue to be lost as primary users retire, relocate, or move on to other projects. There also remains the question of data ownership: how long should recently collected data remain under the exclusive control of the scientists who collected the data? This issue is being addressed by the federal agencies involved in the global change pro gram. Quality Assurance and Documentation Data are frequently separated from information about the data. This is an unfortunate by-product of the explosion over recent decades of digital data and techniques for handling them. Information about the algorithms used for a derived product, quality control procedures, comparisons with independent measurements, reviews by outside experts, and so on, permit the user to judge the reliability or value of the product for a particular application and therefore should be an inseparable part of the data. The same is true for original data in terms of calibration, quality control flags, station histories, and so on. The quality assurance and documentation standards of data sets impor- tant to global change research must be upgraded. Quality assurance and documentation should be at the heart of a data management system supporting the global change program. Only after extensive testing by independent reviewers should important global research data sets be considered accurate. Depending on the data involved, the effort can be extensive and often can be the single most expensive step in processing a data set for distribution. This process, analogous to the independent peer review of a journal article, maximizes the integrity of the information. It is necessary for USGCRP. Future research and policy decisions will rest in part on these important data sets. Documentation must do more than describe the values represented in each field and the format information to read the data tape. It must fully document the data set from all possible points of view. Data documentation must pass the "20-year test." That is, 20 years from now will someone not familiar with the data or how they were obtained be able to fully understand and use the data solely with the aid of the documentation archived with the data set? This is a tough test, and yet one that must be passed for many of the data collections if long-term global environmental programs are to be successful. Cooperation and Sharing For most global change studies, regional and global data and information will be required. No one nation, agency, or institution will be able to gather

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DOCUMENTING GLOBAL CHANGE 239 the appropriate data without cooperation from other nations, agencies, and institutions. In the United States, the USGCRP will depend on scientists sharing their data with each other. The timely submission of data to national centers requires a policy to ensure it. The policy must recognize the needs of principal investigators to protect their intellectual investment and must en- courage their continued efforts to collect useful global change data. REFERENCES Data Management and Computation Committee, National Research Council. 1982. Data Management and Computation, Vol. 1: Issues and Recommendations, National Academy Press, Washington, D.C. Earth System Sciences Committee. 1988. Earth Systems Science: A Closer View. National Aeronautics and Space Administration, Washington, D.C. Geophysical Data Committee, National Research Council. 1990. A U.S. Strategy for Global Change Data and Information Management. In review. Interagency Working Group on Data Management for Global Change. 1990. Rec- ommendations from an Interdisciplinary Forum on Data Management for Global Change. Office for Interdisciplinary Earth Studies, UCAR, Boulder, Cola. International Geosphere-Biosphere Program (IGBP). 1990. The Initial Core Projects. Report to the Second Advisory Council for the IGBP. In preparation. Long-Term Ecological Research (LTER) Network Office. 1989. 1990's Global Change Action Plan: Utilizing a Network of Ecological Research Sites. LTER Network Office, Seattle, Wash. Morel, P. 1990. Satellite Observations and Global Climate Change Research. Space and Global Environment, Paris. National Aeronautics and Space Administration. 1988. NASA Earth Science and Applications Division: Program Plans for 1988-89-90. NASA, Washington, D.C. 133 pp. Panel to Review NASA's Earth Observing System in the Context of the U.S. Global Change Research Program. 1990. Preliminary Report. NRC, March 30. Potential of Remote Sensing for the Study of Global Change. 1987. S.I. Rasool (ed.), Advances in Space Research, Vol. 7, No. 1, Pergamon Press. Rasool, I., and D. Ojima (eds.~. 1989. Pilot Studies for Remote Sensing and Data Management, IGBP Report No. 8, Stockholm, Sweden.

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