June 19, 2003 — Situated in the shadow of the dramatic Flatirons rock outcropping of the Rocky Mountains in Boulder, Colo., is the David Skaggs Research Center, home of the main offices and laboratories of the NOAA Climate Monitoring and Diagnostics Laboratory. CMDL is one of the twelve environmental research laboratories within NOAA Research, six of which are housed in the DSRC. CMDL’s mission is “to acquire, evaluate and make available long-term records of atmospheric gases, aerosol particles and solar radiation in a manner that allows the causes of change to be understood.” As a result, CMDL scientists conduct research along three main themes Global Climate Forcing, Stratospheric Ozone Depletion and Baseline Air Quality. By asking critical scientific questions and conducting detailed and carefully designed research, CMDL scientists provide a basis for assessing the prospects of change in the global climate or in the health of the atmosphere, both of which can significantly affect human health and well-being across the globe.

CMDL provides high-quality measurements of carbon dioxide, methane, nitrous oxide, ozone, chlorofluorocarbons and other ozone depleting gases, solar radiation and aerosols from sites around the world to the scientific community, policy makers and the public. At the DSRC offices, flask air samples — collected worldwide — are analyzed, instruments are developed and improved, data are processed and published and calibration scales are maintained. Most of the staff of 90 work out of the Boulder site. Other CMDL personnel are housed at one of the five staffed CMDL Baseline Observatories: Barrow, Alaska; Mauna Loa, Hawaii; American Samoa; South Pole, Antarctica; or the newest addition; Trinidad Head, Calif. The observatories form the backbone of the global CMDL measurement programs. Some of the measurements at Mauna Loa and South Pole, date back to 1957. Much of the CMDL research is conducted from ground-based stations, but in efforts to understand the origin, fate, and history of atmospheric constituents, measurements are also made from ships, a variety of aircraft and on samples of air collected from polar snow pack.\

Major findings published by CMDL scientists have:

• Documented the global distribution and trends of carbon dioxide and methane,
• Identified the northern hemisphere terrestrial biosphere as a large sink for carbon dioxide,
• Reported the turnaround of ozone-depleting chlorine in the atmosphere,
• Found that the ocean is a sink for a number of ozone depleting gases,
• Provided a 20th century history of climatically important gases in the atmosphere from analysis of air trapped in polar snowpack,
• Determined the non-volcanic, background level of stratospheric aerosols,
• Reported dramatic changes in the global growth rates of atmospheric methane and carbon dioxide
• Documented the 15-yerar history of the ozone hole with balloon measurements at the South Pole, and
• Established a clear correlation between total column ozone and ultraviolet radiation.

CMDL scientists are divided into the following five research groups:

• Aerosols and Radiation: Aerosols are suspensions of solid and liquid particles or droplets in the air and affect the Earth's radiation budget by scattering and absorbing solar radiation. Clouds, pollution haze, desert dust, sea spray, volcanic haze and fog are all examples of aerosols and all have a profound affect on the radiation the surface of the Earth receives. Thus, the study of climate forcing by aerosols is intimately related to studies of solar radiation and the Earth's infrared atmospheric radiation. The Aerosols and Radiation Research Group or AERA is comprised of two sub-units "Aerosols" and "Solar & Thermal Atmospheric Radiation:"
  
  • Aerosols Group: Aerosol measurements began at the CMDL baseline observatories in the mid-1970s as part of the Geophysical Monitoring for Climate Change program. Since the inception of the program, scientific understanding of the behavior of atmospheric aerosols has improved considerably. One lesson learned is that human activities primarily influence aerosols on regional/continental scales rather than global scales. The goals of this regional-scale monitoring program are to characterize means, variability and trends of climate-forcing properties of different types of aerosols, and to understand the factors that control these properties. CMDL's measurements also provide ground-truth for satellite measurements and global models, as well as key aerosol parameters for global-scale models.
    
  • Solar & Thermal Atmospheric Radiation: The STAR group's activities involve empirical and theoretical research of the Earth's surface radiation budget. The group specializes in the investigation of climatically significant variations in long-term radiation and meteorological measurements made primarily at a globally diverse network of surface sites. STAR research interests focus on the extent and cause of observed variations, and in collaborating with other research groups making satellite observations and climate model calculations. STAR also makes some relative observations of spectral solar radiation to assist in remote sensing of certain atmospheric constituents. A relatively new program in the group is the absolute measurement of spectral solar UV for the investigation of the interaction of ozone and solar radiation.
    
• Carbon Cycle Greenhouse Gases Group: The NOAA CMDL Carbon Cycle Greenhouse Gases group makes ongoing discrete measurements from land and sea surface sites and aircraft, and continuous measurements from baseline observatories and tall towers. These measurements document the spatial and temporal distributions of carbon-cycle gases and provide essential constraints to the understanding of the global carbon cycle.
  
• Halocarbons & Other Atmospheric Trace Species Group: The general mission of the Halocarbons and other Atmospheric Trace Species group is to quantify the distributions and magnitudes of the sources and sinks for atmospheric nitrous oxide (N₂O) and halogen containing compounds. HATS utilizes numerous types of platforms, including ground-based stations, towers, ocean vessels, aircraft and balloons to accomplish its mission.
  
• Observatory Operations Group: CMDL operates staffed atmospheric baseline observatories at Barrow, Alaska; Trinidad Head, Calif.; Mauna Loa, Hawaii; Samoa; and the South Pole from which numerous in situ and remote atmospheric and solar measurements are conducted. The overall scientific programs and administrative functions of the four observatories are handled from Boulder with on-site station chiefs caring for day-to-day station activities. The meteorological data from each observatory is monitored, processed and put on the Internet on a daily basis by this group. In addition to the baseline observatories, CMDL also has operations at numerous cooperative sites around the world.
  
• Ozone & Water Vapor Group: The Ozone and Water Vapor Group conducts research on the nature and causes of the depletion of the stratospheric ozone layer and the role of stratospheric and tropospheric ozone and water vapor in forcing climate change and in modifying the chemical cleansing capacity of the atmosphere. This mission is accomplished through long-term observations and intensive field programs that measure total column ozone, ozone vertical profiles (ozonesondes and umkehrs), ground level ozone and water vapor vertical profiles in the upper troposphere and stratosphere and through transport modeling with isentropic trajectories.

Calibration
An important element of CMDL’s operations is the calibration of atmospheric measurements. Because much of what is measured is low in concentration and because measurements are made globally with many instruments, it is imperative that calibrations be of the highest quality. CMDL maintains calibration scales for a number of gases and atmospheric properties (i.e., carbon cycle trace gases and Dobson total column ozone), frequently intercalibrating with other agencies and organizations to ensure consistent measurements across the globe. In addition, CMDL maintains the GLOBALVIEW greenhouse gas data archive that collects data from around the world and puts it into one easily accessible format for use by scientists around the world.

Instrument Development
CMDL is a leader in the development of instrumentation for environmental chemical measurements. These developments have improved dramatically upon the frequency and precision of measurements necessary for monitoring the atmosphere. This is an ongoing process involving improvements of instrumentation for old measurements, as well as new instruments for new constituents or different applications.

CMDL data are used as integral components of the Intergovernmental Panel on Climate Change reports and the WMO/UNEP Scientific Assessments of Ozone Depletion. CMDL scientists are active contributors to and co-authors of these reports. CMDL data are often used for developing global models and for ground-truthing measurements by satellites.

Benefits from the research conducted by CMDL scientists are global in scope. Determining the nature of the full range of climate forcing agents will allow a more certain projection of future climate. The well-being of mankind depends on it, from economic security to personal safety. The public believes that the cause of depletion of the ozone layer had been determined, the cure administered, and that in time the ozone layer will heal. This is only true if replacements for certain chemicals now used as substitutes for chlorofluorocarbons are found and implemented. It is NOAA’s task, assigned by the Clean Air Act of 1990, to monitor both the ozone layer and the chemicals that monitor it. Additionally, CMDL remains at the forefront of monitoring related to the air quality of the country and measures to improve it. Knowledge of the emissions, and the knowledge of emissions entering the country, is necessary for air quality research. CMDL provides data products critical for determining trends and evaluating the causes and feedbacks of these trends in an atmospheric environmental system that is intricately interwoven.

Today, CMDL has proven itself as a laboratory that serves society by providing the best possible information on atmospheric constituents that drive climate change, stratospheric ozone depletion and baseline air quality.

Relevant Web Sites
NOAA’s Climate Monitoring and Diagnostics Laboratory

CMDL’s Baseline Observatories

NOAA Office of Oceanic and Atmospheric Research

NOAA CMDL Aerosols and Radiation Group

NOAA CMDL Carbon Cycle Greenhouse Gases Group

NOAA CMDL Halocarbons & Other Atmospheric Trace Species Group

NOAA CMDL Observatory Operations Group

NOAA CMDL Ozone & Water Vapor Group

Encyclopedia for the Atmospheric Environment (educational resource)

Media Contact:
Jana Goldman, NOAA Research, (301) 713-2483