Strategic Plan for the
Climate Change
Science Program
Review draft, November 2002

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Chapter 3:
Climate Quality Observations, Monitoring, and Data Management

The US Climate Change Research Initiative (CCRI) provides resources to develop climate observation systems. It encourages partnerships with developed countries and support for developing countries in order to build a global observing system. A climate observing system must go beyond climate observations themselves to include the processing and support system that leads to reliable and useful products. To be most effective it must also provide critical data for decision support and policymakers in areas such as climate and weather forecasting, human health, energy, environmental monitoring, and natural resource management. The specific emphasis on climate observing and information systems within CCRI will be to document the past, observe the current state, and archive a high quality and consistent record that is accessible to everyone. These objectives are considered through representative research questions.

Observations of current and past climates play an important role in improving the characterization of processes in the ocean, atmosphere, land surface, and polar regions, and in validation of climate models. The climate record is a time series of key variables, such as temperature, precipitation, and pressure, at monitoring sites or aggregated at regional and/or local levels. These data are essential input to climate models and therefore key to meeting the complex challenge of predicting future climate. The climate record itself provides valuable information for industrial planning in sectors such as electric utilities, transportation, construction, insurance, and many others. The need for refining, extending (both backwards and forwards), and analyzing the long-term climate record to better discriminate natural variability from human-induced global change is self-evident. Space-based and in situ observations, often associated with weather networks, have provided the most important data so far for the detection and attribution of causes of global change. Documentation of decadal to centennial climate changes requires records of much longer duration than available based on modern instrumentation. Therefore, we need a systematic search for, and recovery of, naturally existing proxies (substitutes) for such instrumentation -- proxies that reveal the past history over hundreds and thousands of years with adequate quality and temporal resolution.

Many individuals in many countries have gathered climate system variables using many different instrument types during the past 150 years to document climate system variability. In order to document and understand change from a historical perspective, we need to develop global, comprehensive, integrated, quality-controlled databases of climate system variables based on historical or modern measurements, and to provide the user community with open and easy access to these databases. We need to integrate these records as far into the past as is practical to reduce uncertainties in the climate trend estimates of individual parameters. In addition, we can now reanalyze the past states of the climate system using the modern tools of data assimilation within the context of a numerical global circulation model. These model-based reanalyses have proven successful for the atmosphere and are now being explored for the oceans. A strategy for routine reanalysis must be established to exploit the iterative nature of improvements in this process.

Understanding the magnitude and impact of past climate variations and change is key to developing confidence about how climate may change in the future. This requires comprehensive documentation about the full spectrum of climate forcings, feedbacks, and responses, especially over the past century when human influences have been most pronounced. Although the recent Intergovernmental Panel on Climate Change (IPCC) assessment (IPCC, 2001) provides information about climate changes and variations for a variety of variables, more can be done in an organized and timely way to support climate-related policy. Much of this information is not routinely updated and integrated into a clear comprehensive assessment, nor is it combined into a convenient format for policymakers.

The state of the climate is determined from the global climate observing network. This network is also used to examine the current state relative to the past, often in the form of anomalies (differences) relative to a mean state, and to examine long-term trends of climate-sensitive variables, such as sea level rise, air and sea temperatures, sea ice concentration and extent, and upper ocean heat content. The future state of the climate is predicted by starting from the present state of the climate. The importance of observations for producing an accurate assessment of the present state of the climate is recognized through a core objective of the CCRI.

Climate research and monitoring require an integrated strategy of land, ocean, and atmospheric observations, including both in situ and remote sensing platforms, modeling, and analysis. An adequate global climate observing system should be made up of instruments on various platforms, including aircraft and satellites, ground stations, ships, buoys, floats, ocean profilers, balloons, flux towers, and samplers. The existing network is in need of repair and maintenance, and many elements must be brought up to modern standards.

One of the more pressing needs from a climate monitoring perspective is the identification and correction of time-dependent data biases in observation systems as early as possible. This is a fundamental aspect of scientific data stewardship. Too often, time-dependent biases have been discovered ten or more years after the fact, often through data archaeology or reprocessing efforts. This degrades the climate record, even if adjustments can be developed to correct the deficiencies, and often requires considerable extra effort. Achieving early detection of time-dependent biases will require new research on the most effective means of finding biases early on. In addition, a system must be put in place so that when biases are found, network operators can be notified and corrective action taken. These biases are sometimes due to sensor degradation, but just as frequently result from changes in algorithms or spatial and temporal sampling methods that at first appear innocuous. All these issues will need to be addressed.

The CCRI will enhance the existing long-term monitoring system with accelerated focused initiatives to provide a more definitive observational foundation for determining the current state of the climate. Many shortcomings of the current climate observing system relate to surface and upper air atmospheric measurements and observations of atmospheric composition, global ocean, land surface, and ice variables. For example, only half of the Global Climate Observing System (GCOS) Upper-Air Network (GUAN), established for climate purposes, has been reporting regularly in its first few years of operation, and the GCOS Surface Network (GSN) for climate has had similarly disappointing results. The ocean is poorly observed below the surface and large parts of the ocean have never been measured in some seasons (such as the Southern Hemisphere oceans in winter). Over land, the great spatial heterogeneity requires extremely detailed measurements and presents a major challenge.

A truly global observing system is only possible through international cooperation and coordination. The United States is an active and leading partner in the development and support of a global observing system that assembles key elements from a number of observing networks under the aegis of appropriate international organizations, in particular the Global Observing Systems (G3OS), which include GCOS, the Global Ocean Observing System (GOOS), and the Global Terrestrial Observing System (GTOS). The full implementation of G3OS will require international coordination and commitment. Components for atmospheric, oceanic, terrestrial, and satellite observations are supported at varying levels depending on scientific priorities, availability of national contributions, and the sophistication of the relevant observing technologies.

Climate prediction systems depend on robust and broad global observations to project the present state of the climate into the future. In addition, observations are used to validate and evaluate model predictions, which leads to model improvement. Key variables, such as sea surface temperature, must be available with sufficient accuracy and resolution for prediction systems to provide maximum benefit.

A key role for the CCRI's accelerated focus on observing systems is to reduce the significant uncertainties in our understanding of climate change. A crucial issue that remains unresolved relates to the rate of warming in the troposphere compared to the surface during the latter part of the 20^th century. Climate model simulations, forced by anthropogenic changes in atmospheric composition, project significant increases in tropospheric temperature that are somewhat larger than the increases near the surface in the tropics. Several analyses of the observational data suggest that the rate of warming at the surface has been at least twice that of the troposphere, especially in the tropics and sub-tropics, since about 1980, and about the same since around 1960. The failure of the troposphere to warm at the same rate as the surface during the last few decades has called into question both our understanding of the causes of any change, in particular the impacts of enhanced greenhouse gas concentrations, and the data used to calculate temperature trends. For these reasons, the IPCC's Third Assessment Report (IPCC, 2001) devoted considerable discussion to assessments of both climate model simulations and observational data in order to resolve the apparent differences in the rate of warming projected inaccurately in climate models with those observed in the troposphere and at the surface. Climate models were used to help understand how the surface and tropospheric temperatures may have responded differently to a variety of natural and anthropogenic forcings. Prior to the IPCC report, a panel of the National Research Council (NRC) attempted to reconcile the differences in the observations from satellites, weather balloons, and the near-surface temperature record derived from surface weather stations and ocean ships and buoys (Reconciling Observations of Global Temperature Change, NRC, 2000). The IPCC (IPCC, 2001) concluded that it was very likely that there are significantly different trends of temperature at the surface, in the troposphere, and in the stratosphere.

Several new analyses have been completed since the IPCC and NRC reports were published. The differential surface and tropospheric warming remains a complex issue from an observational standpoint. Several independent estimates of tropospheric temperature trends since 1958, based on radiosondes, have yielded quite different results ranging from little or no warming to 0.2ºC per decade. New and updated analyses of the satellite record indicate warming in the troposphere of more than 0.1ºC per decade in one data set, but only a statistically insignificant trend in another, both over the period 1979 to 2001.

Model simulations have been run to interpret the observational data. Coupled climate models with combined anthropogenic and natural forcings have been unable to simulate the large differences in trends reported by several of the observational analyses. The inability to reliably simulate the observed differential warming is due to a combination of model error and missing or inaccurately specified external forcings, e.g., the effects of increased greenhouse gases and stratospheric ozone depletion in the upper troposphere. An alternate explanation assumes that observational errors are not trivially small. The truth could lie somewhere in the middle.

To help resolve this issue that is central to detecting and attributing climate change, and ensure that future monitoring systems deliver data free of time-dependent biases, a focused effort will be made to ensure improved retrospective and prospective atmospheric temperature measurements. This includes:

Changes in an environmental variable -- most often warming, but also changes in precipitation and air quality -- have often been related to observed changes in biological and ecological systems. Several examples were mentioned in the Working Group II section of the IPCC's Third Assessment Report (IPCC, 2001), including thawing of permafrost, lengthening of the period of leaf display in mid- and high-latitude ecosystems, poleward shifts of plant and animal species ranges, movement of plant and animal species up elevational gradients, earlier spring flowering of trees, earlier spring emergence of insects, earlier egg-laying in birds, and shifts in a forest-woodland ecotone (the boundary between the forest and the woodland). These changes in ecosystems and organisms are consistent with warming and changes in precipitation, but the possibility remains that the observed biological and ecological changes were caused (in part) by other factors such as biological invasions or human land management. Because of this, the attribution of the causes of biological and ecological changes to climatic change or variability is extremely difficult. Moreover, because many ecosystem-environment interactions play out over long periods -- ultimately involving evolutionary changes and adaptations within ecosystems -- long periods of study are needed in many cases to draw firm conclusions about relationships between environmental change, effects of that change on biological and ecological systems, and the significance of any observed biological or ecological changes for the functioning of ecosystems.

New research is needed to provide a significantly more complete picture of how biological and ecological systems may have responded to recent climatic change and variability, including possible biological or ecological responses to extreme events. New observational systems will also be needed to appropriately monitor potential future changes in the environment and accompanying biological or ecological changes (if any). A key challenge will be to provide organization, guidance, and synthesis for the emerging field of observed effects of climate change on biological and ecological systems.

The CCRI will initiate studies of early effects and indicator systems across diverse ecosystems and geographic regions. A substantial amount of existing climate and effects data, a variety of monitoring efforts, and comparisons to scenario-based effects studies can be marshaled in this effort. The CCRI will facilitate linked analyses of climatic trends and observed biological and ecological effects by supporting identification of appropriate past and ongoing monitoring efforts, design of new needed monitoring systems, and synthesis of results across ecosystems and regions. Research efforts will target those ecosystems that are subjected to (or may be subject to in the future) the most rapid or extensive environmental changes and/or are most sensitive to possible environmental changes.

Long-term, spatially explicit, and quantitative observations of ecosystem state variables and concomitant environmental variables are needed. Initial activities will focus on:

The payoff from the initial products will be information needed to establish effective networks of observing systems directed at identifying, quantifying, and explaining resilience as well as changes in ecosystems resulting from global changes. The information will be used to design appropriate observing systems, which will in turn be needed to implement effective observational systems that may be able to provide key information to decisionmakers and scientists about effects of global change on ecosystems. It will begin to lay the foundation for future analyses of how ecosystem responses in turn cause feedbacks to the climate system.

The key priority for scientists and decisionmakers is access to the climate record. Scientists studying Earth system variability and change must have an accurate, uninterrupted series of key geophysical climate data records. These data records stretch from paleoclimatic proxy data to measurements from today's observation systems. To provide maximum accessibility, scientific quality assurance, and ease of utility of these key products spanning multiple decades, multiple projects, and multiple government agencies now and in the future is key to the success of understanding and providing the science-based information that is the mandate of the Climate Change Science Program (CCSP).

The provision of data and information in forms needed for cross-disciplinary analysis and projection remains a challenge. Some science questions by their very nature pose needs for the concerted gathering of "bundles" of data, information, and services. Throughout this document, which discusses key and emerging science questions, are specific needs for data sets related to large regional problems, large-impact processes, field campaigns, and analyses that combine in situ data, remotely sensed data, process studies, and model output. Integrated data set needs are most effectively answered by community-aggregated data, information, tools, and services dedicated to removing usage barriers, such as temporal and spatial differences.

It is now well known that for climate change research, life-cycle data management -- including long-term stewardship -- must be considered and planned throughout the entire design, implementation, and life cycle of any observing system. Long-term stewardship includes the long-term preservation of the scientific integrity of the data, monitoring and improving data quality, significantly enhancing access to the data, and extracting further knowledge from the data.

A continuous and complete data record for the observational instrument series or network of stations, including history and metadata (information about the data set), provides the details necessary to support a high degree of confidence in the data employed by the scientific research community in forecast and prediction modeling. In turn, this provides decisionmakers with a high degree of confidence when making environmental and economic policy decisions. In addition, data collected as part of process studies is of great value for improving the fidelity of climate models. Consequently, data providers must assemble, document, and subject these data to high quality standards. Such data should be assembled, processed, integrated, and made openly accessible to the research community. Adequate support for safeguarding by federal depository centers will ensure long-term access.

As we move to implement the CCRI, achieving integrated (land, atmosphere, and ocean) data access will require multidisciplinary analysis of data and information to an extent never before attempted. This includes the analysis of interlinked environmental changes that occur on multiple temporal and spatial scales, which is very challenging both technically and intellectually. For example, many types of satellite and in situ observations at multiple scales need to be integrated with models, and the results presented in understandable ways to all levels of the research community, decisionmakers, and the public. In addition, very large volumes of data from a wide variety of sources, and results from many different investigations, need to be readily accessible to scientists and other stakeholders in usable forms.

The success of every element in this plan requires accessible, high-quality, interoperable, and thus easily usable, data in order to reduce the uncertainties in our models, and to be able to understand and characterize the processes and feedbacks when addressing the key questions about atmospheric composition, the carbon and water cycles, land use and land cover, ecosystems, and climate variability and change. The data and information must be presented in a way that facilitates its use in scenario development, studies of human contributions and responses to environmental change, and decision support tools. The accessibility of quality data will be a focus of CCRI, and its success will rely on partnerships with existing national and international efforts currently focusing on these issues (i.e., G3OS, Ocean.US, the International Geosphere-Biosphere Programme (IGBP), and the World Climate Research Programme (WCRP)).

NRC, 2000. Commission on Geosciences, Environment and Resources, National Research Council, Reconciling Observations of Global Temperature Change (Washington, DC: National Academy Press, 2000).