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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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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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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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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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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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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.
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Representative terms from entire chapter:
documenting global
