Focus Area

Since 1997, CDIAC has been funded by DOE to provide data management support for the AmeriFlux network. AmeriFlux investigators measure the net flux of CO₂, using the eddy-covariance method, to and from major terrestrial ecosystems. The aim of this long-term, continuous monitoring network is to better understand the factors regulating CO₂ exchange, including soil processes, vegetation structure, physiology, and stage of succession, and to determine principal feedbacks that affect the future, such as response to changes in climate, air pollution, and CO₂ concentrations.

The scientific objectives of AmeriFlux are to establish an infrastructure for guiding, collecting, synthesizing, and disseminating long-term measurements of CO₂, water, and energy exchange from a variety of ecosystems; collect critical new information to help define the current global CO₂ budget; enable improved predictions of future concentrations of atmospheric CO₂; and enhance understanding of carbon fluxes, Net Ecosystem Production (NEP), and carbon sequestration in the terrestrial biosphere.

The present AmeriFlux network now comprises approximately 40 sites in Brazil, Canada, Costa Rica, and the United States. These sites span a large variety of ecosystems, climate regimes, elevations, and stand ages. For more details on AmeriFlux and related data activities, please visit the AmeriFlux Web site at http://cdiac.esd.ornl.gov/programs/ameriflux/.

The primary responsibilities of the CDIAC AmeriFlux data archive are to archive AmeriFlux data forever; check contributed AmeriFlux data to ensure quality and consistency; assemble consistent documentation to ensure long-term use of AmeriFlux data; compile ancillary information for each AmeriFlux site [e.g., leaf area index (LAI), land-use histories] for the purpose of creating network-wide databases; and create and maintain an AmeriFlux Web site.

The AmeriFlux data archive at CDIAC offers two types of AmeriFlux data. Preliminary data are contributed by AmeriFlux principal investigators (PIs). The file formats and contents are unchanged from their original submission state. Any descriptive files provided are those furnished by the site PIs. The values provided in these preliminary files have been scrutinized by the PIs but are subject to change. Preliminary AmeriFlux data are kindly contributed to CDIAC and made available in order to make AmeriFlux measurement data available as quickly as possible.

Preliminary AmeriFlux data sent to CDIAC are checked, processed into a consistent data format, and documented by CDIAC before release as a final data set. All data issues investigated by CDIAC are resolved with the contributing PIs, and no values are changed without the approval of the contributing AmeriFlux PIs.

Noteworthy developments during FY 1999

• Tom Boden replaced Antoinnete Brenkert as the AmeriFlux data manager. Antoinette was the first AmeriFlux data manager and laid much of the existing foundation for the AmeriFlux data archive. Susan Holladay continues to assist with AmeriFlux data activities and Web development.
• Tom Boden attended the AmeriFlux Science Team Meeting at Harvard Forest (October 1998).
• The CDIAC AmeriFlux archive was designated as the hub for an FY 2000 validation exercise. Micrometeorological flux measurements from AmeriFlux sites will be used, along with Gross Primary Production (GPP) estimates obtained from the moderate-resolution imaging spectroradiometer (MODIS) sensor launched December 1999 on the National Aeronautics and Space Administration (NASA) Terra satellite, in the global biome model-biogeochemical cycle (BIOME-BGC) model, and other models, to calculate GPP, NEP, and Net Primary Production (NPP). The model-calculated GPP, NEP, and NPP estimates will then be compared with the same estimates derived from measurements at the individual AmeriFlux sites.

Databases

• The first final database to be posted came from the oldest of the AmeriFlux sites, Harvard Forest, and was contributed by Bill Munger and Steve Wofsy, Harvard University; Dave Fitzjarrald and Kathy Moore, State University of New York (SUNY)-Albany; Mike Goulden, University of California (UC)-Irvine; and Allen Goldstein, UC-Berkeley. The flux, hydrocarbon, and trace-gas profiles provided from the Harvard Forest mixed, deciduous forest site cover the period 1990-1996.
• The second final database to be posted on the AmeriFlux area offers flux measurements for 1995-1996 from an old-growth ponderosa pine site in Metolius Natural Research Area, Oregon. Final The data were contributed by Bev Law, Peter Anthoni, and Michael Unsworth, Oregon State University.
• Preliminary data were posted for the following sites and periods.

Happy Valley, Alaska (moist, acidic tundra) 1994-1995
U-Pad, Alaska (moist, wet sedge tundra) 1994-1995
Bondville, Illinois (agricultural crops, alternating corn and soybeans) 1996-1998
Howland Forest, Maine (boreal, northern hardwood forest) 1996-1997
Little Washita Watershed, Oklahoma (rangeland) 1996-1998
Ponca City, Oklahoma (agricultural crops, wheat) 1996-1997 Final
Shidler, Oklahoma (tallgrass prairie) 1996-1997 Final
Walker Branch Watershed, Oak Ridge, Tennessee (deciduous forest) 1995-1998 Final
BOREAS Northern Study Area, Thompson, Manitoba (old black spruce forest) 1994-1998

Web Developments

• provided all presentations from the October 1998 AmeriFlux Science Team Meeting at Harvard Forest,
• added a new section entitled "Equipment Sources, Tips, and Techniques" to help new and existing AmeriFluxers,
• added a new section entitled "Model Validation" describing the upcoming FY 2000 model validation effort,
• added a paper written by Eva Falge on gap-filling strategies, and
• updated the list of AmeriFlux measurement parameters, standard definitions, and preferred reporting formats and maintained the lists of AmeriFlux sites and participants.

Free-Air CO₂ Enrichment (FACE)

Studies of the effects of CO₂ enrichment on vegetation and ecosystems have always been constrained by the experimental equipment (e.g., open-top chambers), which limited the size and temporal duration of the studies. But in the past few years, the FACE design, pioneered at Brookhaven National Laboratory and now in use or in development at approximately thirty sites around the world, overcomes some of those obstacles and permits more ecologically realistic studies. In FY 1999, CDIAC began a web site for FACE (http://cdiac.esd.ornl.gov/programs/FACE/face.html).

This site provides a network for the many FACE experiments under way or planned. CDIAC's FACE site provides background information about the FACE research approach and shows the sites and summary information about each experiment, with links to contacts for each study. It also provides a listing of FACE-related publications. The initial design and construction of the site was handled by CDIAC summer student Stephen Henderson from Allegheny College; following Stephen's return to school in the fall, Bob Cushman and Sonja Jones continued to develop the site. We hope to move more actively into the management of data from FACE research.

FACE Sites Around the World

NARSTO is a nonbinding, tri-national public/private alliance, open to science agencies, regulatory agencies, regulated industries, academic institutions, environmentalists, and public interests groups in Canada, Mexico, and the United States. Its primary mission is to coordinate and enhance policy-relevant scientific research, assessment, and modeling of tropospheric pollution behavior, with the central programmatic goal of determining workable, efficient, and effective strategies for local and regional air-pollution management.

In January 1997, DOE's Environmental Sciences Division began their sponsorship of the NARSTO Quality Systems Science Center (QSSC) within CDIAC. The QSSC reports to the NARSTO Executive Steering Committee through the NARSTO Management Coordinator and collaborates with the Science Teams.

The QSSC works to ensure that relevant quality management systems are planned and implemented by NARSTO technical programs. The NARSTO Quality Systems Management Plan (QSMP) and the Quality Planning Handbook (QPHB), developed and maintained by the QSSC, form the umbrella under which all quality-related activities are conducted.

The QSSC reviews project management and fieldwork planning documents and provides information to NARSTO partners seeking assistance with quality assurance, quality control, data management, and data archival. The QSSC plans and coordinates NARSTO data management, data archival, and data dissemination activities. Timely sharing of and access to quality assured NARSTO data and research products (e.g., computer models, methods, procedures, and reports) by the scientific community is essential to the success of the NARSTO program. The QSSC developed and maintains the NARSTO Data Management Handbook (DMHB) that contains data format conventions, data validation guidance, and data archive transfer format specifications. The QSSC performs a final quality assurance check of data sets submitted for archival, prepares archive documentation, and coordinates their transfer to the publicly available NARSTO Permanent Data Archive at the NASA Langley Distributed Active Archive Center (DAAC). Data are online at http://eosweb.larc.nasa.gov/.

NARSTO quality systems and data management documents are available online at http://cdiac.esd.ornl.gov/programs/NARSTO/.

In addition to these quality and data management activities, the QSSC designed and continues to develop the NARSTO Measurement Methods Compendium Web site for ozone and particulate matter sampling and analysis technologies and methodologies. Method descriptions are available online at http://narsto.esd.ornl.gov/Compendium/.

QSSC staff expertise includes atmospheric chemistry, quality systems management, environmental data quality management, and data management coordination.

The FY 1999 QSSC's activities fall into three general areas: quality management support, data quality assurance and archiving, and external interactions.

Quality Management Support

The QSSC updated two of the quality management documents, the QSMP and the DMHB, to reflect NARSTO's changing scope and several refinements in data archive format guidance.

The QSSC initiated the NARSTO Measurement Methods Compendium Web site for ozone and particulate matter sampling and analysis technologies and methodologies. Added first were method descriptions for Federal Reference Methods (FRM) and Federal Equivalent Methods (FEM) for ozone, nitrogen dioxide (NO₂), and carbon monoxide (CO). The FRM/FEM sampling method descriptions were added for particulate matter (PM10 and PM2.5). For organics, two tables of sampling and analysis summary information for Photochemical Assessment Monitoring Stations (PAMS) volatile organic compound (VOC) target species and non-methane organic compound (NMOC) method descriptions were added.

Interactions with NARSTO technical partners included assisting the with reviews of work wlans, requests for proposals (RFPs), proposals, and data management system design. We also provided quality management documentation to several academic institutions.

Data Quality Assurance and Archiving

The QSSC evaluated data sets submitted for archival, prepared archive documentation, and coordinated their transfer to the NARSTO Permanent Data Archive at the NASA Langley DAAC. The NARSTO 1998 Model-Intercomparison Study Verification Data: NARSTO-Northeast 1995 Surface Ozone, NO, and NO_x and the NARSTO-NE 1995 NEXRAD image data were submitted.

The QSSC also provided NARSTO-Northeast and NARSTO-Canada East with data quality assurance feedback and continue to work with them to resolve data quality issues.

External Interactions

QSSC promotes coordination of NARSTO Data Exchange standards and automated processing programs with Bill Sukloff of the Atmospheric Environment Service (AES) of Canada. We leverage existing resources (people and software) to the benefit of both programs. The QSSC cosponsored a 10-day visit by Bill Sukloff for this purpose.

The QSSC sponsored the 12-month appointment of a student from the Oak Ridge Institute for Science and Education (ORISE) Technical Intern Program. Robert Lowery, gathered methods information for the Methods Compendium. The QSSC also sponsored a DOE Energy Research Undergraduate Laboratory Fellowship (ERULF) summer student, Craig Harvey, to evaluate ozone forming potential at several northeastern U.S. sites.

QSSC Staff gave presentations on the Data Exchange Standard at the World Meteorological Organization (WMO) meeting last year in Norway and for a recent visitor from Japan.

QSSC staff participated in NARSTO-sponsored meetings and workshops including the NARSTO Fine Particle Workshop, January 26-29, 1999, and the "Expert Workshop on Monitoring and Assessment in Support of the Sound Management of Chemicals Initiative" sponsored by the North American Free Trade Agreement (NAFTA) Commission on Environmental Cooperation, May 3-4, 1999.

Ocean Data

The World Ocean Circulation Experiment (WOCE) Hydrographic Program (WHP) is a major component of the World Climate Research Program with the overall goal to better understand the ocean's role in climate and climatic changes resulting from both natural and anthropogenic causes. The levels of CO₂ in the oceans are unevenly distributed because of complex circulation patterns and biogeochemical cycles. Although total CO₂ (TCO₂) is not an official WOCE measurement, a coordinated effort, supported in the United States by DOE, was made on WOCE cruises through 1998 to measure the global spatial and temporal distributions of TCO₂ and other related parameters. Goals of the survey were to estimate the meridional transport of inorganic carbon in a manner analogous to the estimation of the transport of oceanic heat, and to build a database suitable for carbon cycle modeling and the estimation of anthropogenic CO₂ increase in the oceans. The CO₂ survey took advantage of the sampling opportunities provided by the WHP cruises during this period. The final data set is expected to cover ~23,000 stations from 42 WOCE cruises.

CDIAC provides data management support for the Joint Global Ocean Flux Study (JGOFS) CO₂ measurements taken aboard research vessels during WHP cruises. The DOE sponsored CO₂ measurement operations and continues to sponsor CDIAC's data support activities, which include data archival, data checking and evaluation, preparation of data documentation, and data dissemination. All CO₂-related data are checked before documentation and distribution. Through the end of FY 1999, DOE-supported investigators had collected CO₂ measurements on 42 WOCE cruises. CDIAC has received data from 38 of these cruises, and 25 of these data sets have undergone quality assurance checks with 10 fully documented as NDPs.

One of the noteworthy developments is the willingness of scientists supported by the National Oceanic and Atmospheric Administration's (NOAA) Ocean-Atmosphere Carbon Exchange Study (OACES) to archive their CO₂-related measurements at CDIAC for comparison, documentation and distribution purposes. Two documents that provide data obtained during NOAA/Pacific Marine Environment Laboratory (PMEL) cruises in the Pacific and Indian oceans have been recently completed at CDIAC.

As new measurements are made and submitted to CDIAC, it will be possible to compare measure-ments obtained at identical locations during different expeditions to assess their agreement. This is particularly important for measurements made in deep and abyssal waters. These checks will assess the geographical consistency of the CO₂-related parameters (TCO₂, pCO₂, alkalinity, and pH), salinity, and the concentrations of dissolved oxygen and macro-nutrients along constant seawater density surfaces.