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Air Quality Forecasting


Research Projects at ARL

Weather and Air Quality

The origins of NOAA ARL lie in the early need to predict the transport and dispersion of radionuclides generated by tests of nuclear weapons in the 1950s. Since those early days, the relevance of this particular mainstream element of ARL research has extended to a number of topical areas, ranging from acid rain to emergency response; however, the dominant research thrust of ARL remains the study and the prediction of atmospheric transport and dispersion.

ARL conducts research into the processes that influence atmospheric motions on virtually all scales, from local (where topography often dominates) to global. ARL focusses on those aspects of the overall transport and dispersion problem that contribute the greatest uncertainty to predictions and assessments.

The end product of ARL research is an improved
												capability to predict air qualityMeteorological models have classically concentrated attention on those regions of the atmosphere in which weather systems generate and move. NOAA experience in using these models has demonstrated the need for a more comprehensive and physically correct way of expressing boundary layer processes. This is especially important for predicting air quality; the atmospheric features that affect air quality tend to be strongly moderated by the planetary boundary layer. (The PBL is defined as the lower part of the atmosphere from the surface up to the level of the geostrophic wind; it is that part of the atmosphere in contact with the surface within which surface-generated convection and mixing is enveloped.)

Characteristics of the PBL are controlled by the surface energy budget, terrain, and vegetation; in turn, the characteristics of the PBL control wind fields and dispersion of trace gases and particles carried by air near the surface. Thus, it is a major thrust of ARL research to improve understanding (and depictions) of all factors that influence the PBL, especially the three central considerations of heat energy, topography, and vegetation. It is for this fundamental reason that ARL maintains and operates several research networks, each designed to provide data with which to test the new models as they are developed and to provide data for future assimilation by these models. These surface networks address various meteorological and air quality properties, as well as surface radiation, which is the driving force for mixing in the PBL. It is anticipated that the next generation of meteorological models will be driven by data derived from advanced networks such as these, and will be adjusted according to observations of key diagnostic variables such as air quality and atmospheric deposition rates. It is recognized that modern models are invariably data assimilative, and that modern monitoring programs require coupled modeling activities for data interpretation.

Air quality simulation Increased awareness of national air quality issues on the part of the media and the general public have recently led to more demand for short-term (1-2 day) air quality forecasts for use in assessing potential health impacts (e.g., on children, the elderly, and asthmatics) and potential mitigation actions in local communities (e.g., increased use of carpools and mass transit, decreased industrial operations). An emerging collaborative partnership between U.S. EPA and NOAA will bring the strengths of these two Agencies' capabilities in atmospheric measurements and modeling in developing an operational capability for producing national modeling guidance for short-term air quality forecasts for ozone and particulate matter in 2004.

Coastal and Ocean Resources

Text summaryPopulation growth and associated increases in demand for energy, consumer goods, and transportation are causing a slow deterioration of almost all east coast aquatic ecosystems. The cause is mainly eutrophication, due to excessive nitrogen and resulting in nuisance algal blooms and loss of habitat. In some areas, however, the problem is not nutrients so much as toxic chemicals (e.g. mercury, in parts of Florida, and persistent organic pollutants for the Great Lakes). The nitrogen compounds of relevance in the East Coast case come from a variety of sources, including sewage, waste water run-off, and agricultural fertilizers, but it is now known that a substantial part is derived from the atmosphere. Regulatory strategies that fail to recognize that part of the problem arises from atmospheric deposition will not work as expected. There is urgent need for integrated assessments that reveal the relative importance of atmospheric deposition as a mechanism for loading to estuaries and other coastal waters. NOAA is serving as a provider of scientific guidance to the rapidly evolving community that is coupling air and water issues in regulatory contexts.

BoaterMeasurement and modeling of atmospheric deposition are long-standing ARL specialties. ARL personnel from three divisions (Research Triangle Park, Oak Ridge, and Silver Spring) have joined forces to study the problem, concentrating primarily on the Chesapeake Bay and its watershed but also reaching out to the entire east coast, from Maine to Florida. ARL is leading a large part of the integrated research effort focusing on this issue. The research that is being conducted stretches from exploratory studies of ammonia and ammonium to the effects of plumes generated from urban areas. ARL activities are coupled with those of all other agencies active in the region, especially EPA, USDA, and DoI.

Understanding of how air pollution affects aquatic ecosystems is necessary to ensure that future (and existing) regulatory efforts to protect and restore estuaries and other habitats along the East Coast will have the consequences that are intended. If the atmosphere is not taken into account, then there is fear that regulations to improve aquatic habitats will be inadequate. We are striving for the understanding required to have a "no surprises" regulatory environment, and for the knowledge that will permit new environmental policy to be appropriately targeted on the "pressure points" where optimal results can be promised, with minimal cost.



Climate research has a long history in ARL. Since 1962, when ARL assumed responsibility for the monitoring programs at Mauna Loa Observatory, ARL has been collecting and analyzing climate data. Ozone monitoring began in the early 1960s. The program at Mauna Loa became the nucleus of ARL's Geophysical Monitoring for Climate Change program formed in the early 1970s. (GMCC became the principal component of the Climate Monitoring and Diagnostic Laboratory when it was formed in 1990.) ARL also established a solar radiation monitoring network in 1975. Analyses of U.S. sunshine and cloudiness records (from 1950 onward) and global temperatures (since 1958) were begun in the mid-1970s and analysis of global tropospheric water vapor changes was added in the mid-1980s.

Current climate research has been stimulated by the potential of human activities to bring about substantial changes in the environment. However, an understanding of natural variability, the "noise" from which any anthropogenic signal must be extracted, is necessary before any change can be unequivocally ascribed to human activities.

The ARL Climate Variability and Trends Group studies diurnal to multi-decadal variations in the global climate system, with a focus on analysis of observational data. This involves extracting climate signals from the noise inherent in standard surface and upper-air meteorological observations, with particular attention to data quality. We also investigate aspects of climate variability that impact human health and environmental quality, including stratospheric ozone, air quality, and climate extremes.

The research program at the Surface Radiation Research Branch of ARL is centered on the interpretation of surface radiation measurements, instrument characterization, and calibration. Currently, the areas of emphasis are: 1) analyses of the surface radiation for trends and regional characteristics, 2) modeling the radiative transfer process as a means of inferring the effects of clouds, aerosols and ozone on the transmission of visible radiation and UV, 3) evaluating the field performance characteristics of UV, visible and IR radiometers to improve our understanding of their behavior, 4) developing rigorous laboratory methods for characterizing and calibrating UV instruments (because of the difficulty in making reliable measurements in the UV-B region of the solar spectrum), 5) comparing surface measurements with those made or inferred from other observing systems such as satellites, and 6) the development of new instruments to provide ancillary information that will aid in the interpretation of the SURFRAD and other surface radiation measurements.

Emergency Assistance

Nuclear power plant

ARL serves as a center of activity for the provision of specialized meteorological assistance in the event of releases of hazardous materials into the atmosphere, such as from volcanoes, nuclear accidents, terrorist incidents, and industrial disasters. NOAA provides basic meteorological support in all such cases, but is also expected to provide transport and dispersion guidance to other Federal agencies.

Much of ARL's work in this area is in conjunction with the NOAA National Weather Service (NWS) and other Federal agencies. ARL provides vital meteorological support to various agencies, (a) to help predict the dispersion of material from an hazardous release into the air, (b) to develop appropriate response strategies,and (c) to provide meteorological assistance in the event of an incdident requiring NOAA support. Work concentrates on dispersion from releases of nuclear materials, industrial accidents (e.g. Bhopal), and volcanic eruptions (Mt. St. Helens, Mt. Redoubt). In this context, NOAA is viewed by other agencies as a source of high-quality and independent scientific and technical expertise.

For this purpose, ARL (as a joint activity with the NOAA National Centers for Environmental Prediction - NCEP ) operates a Regional Specialized Meteorological Center for the WMO, to provide emergency response assistance to the nations of North and Central America in the event of a disastrous accident that releases hazardous material into the atmosphere.

For the case of volcanoes, ARL is joined with NOAA NCEP in a Volcanic Ash Advisory Center activity, to disseminate warnings to air traffic about the presence of volcanic ash clouds. The global array of VAACs is organized under the sponsorship of the International Civil Aviation Organization (ICAO).

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