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Atmospheric Modeling Division Publications: 1999

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This page lists publication titles, citations and abstracts produced by NERL's Atmospheric Modeling Division for the year 1999, organized by Publication Type. Your search has returned 32 Matching Entries.

See also Atmospheric Modeling Division citations with abstracts: 1999,  2000,  2001,  2002,  2003,  2004,  2005,  2006,  2007,  2008,  2009

Technical Information Manager: Liz Hope - (919) 541-2785 or hope.elizabeth@epa.gov

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Presented/Published
JOURNAL Simulation of Aerosol Dynamics: A Comparative Review of Algorithms Used in Air Quality Models 12/01/1999
Zhang, Y., C. Seigneur, J. H. Seinfeld, M. Z. Jacobson, AND F S. Binkowski. Simulation of Aerosol Dynamics: A Comparative Review of Algorithms Used in Air Quality Models. AEROSOL SCIENCE AND TECHNOLOGY 31(6):487-514, (1999).
Abstract: A comparative review of algorithms currently used in air quality models to simulate aerosol dynamics is presented. This review addresses coagulation, condensational growth, nucleation, and gas/particle mass transfer. Two major approaches are used in air quality models to represent the particle size distribution: (1) the sectional approach in which the size distribution is discretized into sections and particle properties are assumed to be constant over particle size sections and (2) the model approach in which the size distribution is approximated by several modes and particle properties are assumed to be uniform in each mode. The sectional approach is accurate for coagulation and can reproduce the major characteristics of the evolution of the particle size distribution for condensational growth with the moving-center and hybrid algorithms. For coagulation and condensational growth, the model approach provides more accurate results when the standard deviations of the modes are followed to vary than it does when they are fixed. Predictions of H2SO4 nucleation rates are highly sensitive to environmental variables and simulation of relative rates of condensation on existing particles and nucleation is a preferable approach. Explicit treatment of mass transfer is recommended for cases where volatile species undergo different equilibrium reactions in different particle size ranges (e.g., in the presence of coarse salt particles). The results of this study provide useful information for use in selecting algorithms to simulate aerosol dynamics in air quality models and for improving the accuracy of existing algorithms.

JOURNAL Dynamically Consistent Formulations in Meteorological and Air Quality Models for Multiscale Atmospheric Studies Part I: Governing Equations in a Generalized Coordinate System 11/30/1999
Byun, D W. Dynamically Consistent Formulations in Meteorological and Air Quality Models for Multiscale Atmospheric Studies Part I: Governing Equations in a Generalized Coordinate System. Journal of Atmospheric Sciences 56(21):3789-3807, (1999).
Abstract: There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.

JOURNAL Dynamically Consistent Formulations in Meteorological and Air Quality Models for Multiscale Atmospheric Studies Part II: Mass Conservation Issues 11/30/1999
Byun, D W. Dynamically Consistent Formulations in Meteorological and Air Quality Models for Multiscale Atmospheric Studies Part II: Mass Conservation Issues. Journal of Atmospheric Sciences 56(21):3808-3820, (1999).
Abstract: There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.

JOURNAL Emission of Pesticides Into the Air 10/01/1999
Van den Berg, F., R. Kubiak, W G. Benjey, M. S. Majewski, S. R. Yates, G. L. Reeves, J. H. Smelt, AND A. A. Van der Linden. Emission of Pesticides Into the Air. WATER, AIR, AND SOIL POLLUTION 115(1-A):195-218, (1999).
Abstract: During and after the application of pesticide in agriculture, a substantial fraction of the dosage may enter the atmosphere and be transported over varying distances downwind of the target. The rate and extent of the emission during application depends primarily on the application technique and the formulation, whereas the emission after application depends primarily on the properties of the pesticide, soils and environmental conditions. The fraction of the dosage that misses the target (spray drift) may be high in some cases and more data on this loss term is needed for various application types and weather conditions. Such data are necessary to test spray drift models, and for further model development and verification as well. The emission of soil fumigants and soil incorporated pesticides into the air after application can be measured with reasonable accuracy, but current models are inadequate in predicting the volatilization rate under general conditions, as a result, further model development is needed to improve their reliability. For soil surface applied pesticides reliable measurement methods are available, but there is not yet a reliable model. Further model development is required which must be verified by field experiments. Few data are available on pesticide volatilization from plants and more field experiments are also needed to study the fate processes on the plants. Once this information is available, a model needs to be developed to predict the volatilization of pesticides from plants, which, again, should be verified with field measurements. For regional emission estimates, a link between data on the temporal and spatial pesticide use and a geographical information system for crops and soils with their characteristics is needed.

JOURNAL A Study of the Relationship Between Photochemical Ozone and Its Precursor Emissions of Nitrogen Oxides and Hydrocarbons in the Tokyo and Surrounding Areas. 08/01/1999
Wakamatsu, S., I. Uno, T. Ohara, AND K L. Schere. A Study of the Relationship Between Photochemical Ozone and Its Precursor Emissions of Nitrogen Oxides and Hydrocarbons in the Tokyo and Surrounding Areas. ATMOSPHERIC ENVIRONMENT 33:3097-3108, (1999).
Abstract: There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.

JOURNAL The Electrical Analogy Does Not Apply to Modeling Dry Deposition of Particles 04/01/1999
The Electrical Analogy Does Not Apply to Modeling Dry Deposition of Particles. ATMOSPHERIC ENVIRONMENT 33(18):3075-3076, (1999).
Abstract: There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.

JOURNAL A Climatology of Total Ozone Mapping Spectrometer Data Using Rotated Principal Component Analysis 02/20/1999
Eder, B K., S K. LeDuc, AND J E. Sickles II. A Climatology of Total Ozone Mapping Spectrometer Data Using Rotated Principal Component Analysis. JOURNAL OF GEOPHYSICAL RESEARCH 104(D3):3691-3709, (1999).
Abstract: There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.

NEWSLETTER Models-3 (Cmaq). Narsto News (Vol. 3, No. 2, Summer/Fall 1999) 11/01/1999
LeDuc, S K. AND J E. Pleim. Models-3 (Cmaq). Narsto News (Vol. 3, No. 2, Summer/Fall 1999). NARSTO News, Pasco, WA, (2), 1999.
Abstract: A revised version of the U.S. EPA's Models-3/CMAQ system was released on June 30, 1999. Models-3 consists of a sophisticated computational framework for environmental models allowing for much flexibility in the communications between component parts of the system, in updating or replacing components, and in the graphical?user interface. The revised Models?3 framework (Version 3.0) is operational on SUN workstations (OS: Solaris 5.6, development version), contains Vis5D and PAVE visualization packages, and utilizes the IBM DX Explorer graph ics/analysis software which is now freely available. Testing of the Models-3 framework on a single Windows NT platform is in progress as well as a version which requires both a Silicon Graphics (SGI) platform and a Windows NT platform. The Models-3 framework will be limited to those platforms presently being tested.
The science code which comprises the Community Multiscale Air Quality (CMAQ) model can be used outside the Models-3 framework and users can adapt code to be compiled and executed on their UNIX computing platform. The capabilities of the CMAQ model are described later.

PRESENTATION Dry Deposition of Pollutants to Forests 12/13/1999
Finkelstein, P L., T G. Ellestad, J F. Clarke, AND T. P. Meyers. Dry Deposition of Pollutants to Forests. Presented at American Geophysical Union Fall Meeting, San Francisco, CA, December 13-17, 1999.
Abstract: We report on the results of an extensive field campaign to measure dry deposition of ozone and sulfur dioxide to a sample of forest types in the United States. Measurements were made for full growing seasons over a deciduous forest in Pennsylvania and a mixed deciduous-coniferous forest in New York, as well as a month long series of measurements over a pine plantation in North Carolina. Seasonal and average diurnal patterns of flux and deposition velocity, as well as the effects of sunlight, plant growth rate, and surface moisture are reported and contrasted for each pollutant. The differences in deposition velocity between ozone and sulfur dioxide deposition velocity are attributed to their different surface resistances, recognizing that ozone is taken up almost exclusively through the stomata while sulfur dioxide may be deposited on the plant cuticle and other surfaces. Observations are compared with the Meyers Multi-Layer Deposition Velocity Model. The strengths of the model are noted, as are the opportunities for improvement.

PRESENTATION Estimating Gaseous Exchanges Between the Atmosphere and Plants Using a Coupled Biochemical Dry Deposition Model 12/13/1999
Wu, Y., B. Brashers, P L. Finkelstein, AND J E. Pleim. Estimating Gaseous Exchanges Between the Atmosphere and Plants Using a Coupled Biochemical Dry Deposition Model. Presented at American Geophysical Union Fall Meeting, San Francisco, CA, December 13-17, 1999.
Abstract: To study gaseous exchanges between the soil, biosphere and atmosphere, a biochemical model was coupled with the latest version of Meyers Multi-Layer Deposition Model. The biochemical model describes photosynthesis and respiration and their coupling with stomatal resistance for both sunlit and shaded leaves. Various aspects of the photosynthetic process in both C3 and C4 plants are considered in the model, such as the efficiency of the photosynthetic enzyme system, the amount of photosynthetically active radiation and the capacity of the leaf to export or utilize the products of photosynthesis. In addition, a normalized soil water stress factor was applied to the potential photosynthesis to account for plant response to both drought and waterlogging stresses. The model can account for the direct, indirect and tightly coupled effects of environmental factors on stomatal regulation of gaseous exchanges between plants and their environment. The coupled biochemical dry deposition model was tested against eddy correlation data from six field experiments. It is shown that the coupled model is able to estimate water vapor, carbon dioxide and ozone fluxes correctly, and the model results compare well with measurements made in the field. The model is for use in the nationwide dry deposition network?CASTNet, and will assist in detecting total pollutant loadings to major ecosystems.

PRESENTATION Estimating Transport and Deposition of a Semi-Volatile Compound With a Regional Photochemical Model 12/13/1999
Hutzell, W T. Estimating Transport and Deposition of a Semi-Volatile Compound With a Regional Photochemical Model. Presented at 1999 Fall Meeting of the American Geophysical Union, San Francisco, CA, December 13-17, 1999.
Abstract: To simulate the fate of compounds that are considered semi-volatile and toxic, we have modified a model for regional particulate matter. Our changes introduce a semi-volatile compound into the atmosphere as gaseous emissions from an area source. Once emitted, the gas can transform via OH addition or partition onto ambient particulate matter as a trace species. The partitioning assumes equilibrium between the gas and particulate phases. Concentrations in each phase then depend on the total ambient concentration and partitioning ratios. The latter values include adsorption and absorption processes based on empirical and theoretical work. Besides these chemical and physical processes, the compound undergoes advection, diffusion, and deposition. The revised model, the Community Multi-scale Air Quality (CMAQ) model, better assesses the atmospheric fate of semi-volatile and toxic compounds because of the way that it estimates particulate matter in the lower troposphere. The estimate uses a tri-modal distribution and internal mixture of inorganic and organic species to describe particulate matter. Air emissions, thermodynamic relations, and gas phase chemistry control production for each species while equations describing aerosol microphysics govern their concentrations over the particulate modes. Particulate concentrations are also controlled by independent transport and deposition algorithms. The CMAQ model then enables assessing how variations in meteorology and particulate matter combine to transform semi-volatile compounds over regional and local scales.
Using the modified model on a herbicide called Atrazine; the application uses emissions of Atrazine predicted by data on annual usage, and a soil model under energy balance conditions. The model domain covers the Eastern US and the simulation spans several days in early July of 1995. Results include atmospheric concentrations and deposition rates. These results may have limited ability to reproduce actual values because the simulation period does not cover a majority of Atrazine emissions. Results illustrate how partitioning can affect the fate of a semi-volatile compound and what sorption processes control partitioning. Results also demonstrate that the CMAQ model can support further research on how regional particulate matter influence atmospheric chemistry and physics.


PRESENTATION On Aerodynamic and Boundary Layer Resistances Within Dry Deposition Models 12/13/1999
Brashers, B., Y. Wu, J E. Pleim, AND P L. Finkelstein. On Aerodynamic and Boundary Layer Resistances Within Dry Deposition Models. Presented at American Geophysical Union Fall Meeting, San Francisco, CA, December 13-17, 1999.
Abstract: There have been many empirical parameterizations for the aerodynamic and boundary layer resistances proposed in the literature, e.g. those of the Meyers Multi-Layer Deposition Model (MLM) used with the nation-wide dry deposition network. Many include arbitrary constants or parameters that are difficult to determine a priori, such as a typical leaf diameter. These become, in effect, tunable parameters. Although they can be used to minimize the difference between observations and models for specific sites, they can vary from site to site and add to the difficulty in working with large-scale projects. Some of the popular parameterizations of the aerodynamic resistance employ drastic restrictions, or are discontinuous functions of their inputs. Many take into account only shear-driven turbulence, ignoring the effects of buoyancy and stratification. We present a simple closed-form parameterization for the aerodynamic resistance based on theoretical arguments. Monin-Obukhov (MO) similarity theory and the associated Businger-Dyer stratification corrections are used to estimate the aerodynamic resistance. Differences in functional form between the MO and resistance frameworks are discussed. A short review of boundary layer resistance parameterizations is presented, and a theoretically-based form is chosen. Differences between eddy correlation measurements over various crops and forests and the MLM, with both the standard and new resistances, are presented.

PRESENTATION Simulating Atmospheric Exposure in a National Risk Assessment Using An Innovative Meteorological Sampling Scheme 11/14/1999
Schwede, D B., W B. Petersen, R. W. Brode, AND M. Jindal. Simulating Atmospheric Exposure in a National Risk Assessment Using An Innovative Meteorological Sampling Scheme. Presented at Society of Environmental Toxicology and Chemistry Annual Meeting, Philadelphia, PA, November 14-18, 1999.
Abstract: Multimedia risk assessments require the temporal integration of atmospheric concentration and deposition with other media modules. However, providing an extended time series of estimates is computationally expensive. An alternative approach is to substitute long-term average atmospheric estimates, but traditional methods for calculating long-term averages are not amendable to estimating wet deposition. In an effort to produce the required estimates without the computational burden, we developed an extension to the Sampled Chronological Imputed Model (SCIM) for use in ISCST3. SCIM samples the long term meteorological record at regular, user-specified intervals. Since hourly meteorology is being used, the serial correlation between wet deposition and concentration is maintained. Our results show that, for a 5 year meteorological-database, sampling every 193rd hour produced concentration and dry deposition estimates essentially the same as those obtained when using the full meteorological record. However, this simple sampling scheme significantly underestimated wet deposition, particularly at sites with infrequent precipitation. For wet deposition, the key to the success of SCIM is the addition of an additional sampling interval (every 8th hour)for hours with precipitation . this approach resulted in wet deposition estimates that were not significantly different than those obtained from the full record. The development of this innovative sampling approach has resulted in an efficient methodology for use in multimedia risk assessments.

PRESENTATION Development of a Microscale Emission Factor Model for CO (Microfacco) for Predicting Real-Time Vehicle Emissions 10/26/1999
Singh, R. B. AND A H. Huber. Development of a Microscale Emission Factor Model for CO (Microfacco) for Predicting Real-Time Vehicle Emissions. Presented at Emission Inventory: Regional Strategies for the Future, Raleigh, NC, October 26-28, 1999.
Abstract: The United States Environmental Protection Agency's National Exposure Research Laboratory has initiated a project to improve the methodology for modeling human exposure to motor vehicle emissions. The overall project goal is to develop improved methods for modeling the source through the air pathway to human exposure in significant microenvironments of exposure. The PART models (used in the United States, except California) and EMFAC models (used in California only) used to estimate emissions are suitable only for regional (county) scale modeling and emission inventories because of their dependence on aggregated vehicle-miles-traveled data. These emission models are not designed to estimate real-time emissions needed for human exposure studies near roadways. Therefore, there is a need to develop site-specific real-time emission factor models for PM emissions.
A microscale emission factor model for predicting site-specific real-time motor vehicle particulate matter (MicroFacPM) emissions for TSP, PM10 and PM2.5 has been developed. It uses site-specific available information on the vehicle fleet composition. The algorithm used to calculate emission factors in MicroFacPM is disaggregated based on the site-specific vehicle fleet. The emission factors are calculated from a real-time fleet, rather than from a fleet-wide average estimated by a vehicle-miles-traveled weighting of the emission factors for different vehicle classes. MicroFacPM requires input information necessary to characterize the site-specific real-time fleet being modeled. Other variables required are average vehicle speed, time and day of the year, ambient temperature and relative humidity.

PRESENTATION Examining the Temporal Variability of Ammonia and Nitric Oxide Emissions from Agricultural Processes 10/26/1999
Pierce Jr., T E. AND L. W. Bender. Examining the Temporal Variability of Ammonia and Nitric Oxide Emissions from Agricultural Processes. Presented at AWMA/EPA Emission Inventory Conference, Raleigh, NC, October 26-28, 1999.
Abstract: This paper examines the temporal variability of airborne emissions of ammonia from livestock operations and fertilizer application and nitric oxide from soils. In the United States, the livestock operations and fertilizer categories comprise the majority of the ammonia emissions inventory. Air quality modeling efforts for the most part have assumed annual-average ammonia emission factors. Based on a literature review, we have generated crude seasonal adjustments of ammonia emissions taking into account climatic factors, manure spreading, and fertilizer application schedules. Nitric oxide (NO) emissions from soils estimated with the Biogenic Emissions Inventory System (BEIS2) comprise about 10% of total annual nitric oxide emissions across the United States. BEIS2 distributes emissions by land use and modulates emissions based on hourly soil temperature, with the highest emissions arising from fertilized soils during warm conditions. A new algorithm has been developed that incorporates daily rainfall patterns, fertilizer application schedules, and plant canopy growth. Simulations with this new algorithm show more short-term variability and an over reduction in soil NO emissions compared to the BEIS2 algorithm, particularly in the Midwestern United States. The techniques introduced for estimating the temporal variability of ammonia and nitric oxide emissions from agricultural operations may help improve the accuracy of fine particulate and ozone models.
This paper has been reviewed in accordance with the U.S. Environmental Protection Agency's peer and administrative review policies and approved for presentation and publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.

PRESENTATION Atmospheric Science Librarians International Mission Statement, Members, and Member Organizations 10/16/1999
PooleKober, E M. Atmospheric Science Librarians International Mission Statement, Members, and Member Organizations. Presented at 25th Annual IAMSLIC Conference, Woods Hole, MA, October 16-22, 1999.
Abstract: There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.

PRESENTATION Mercury Modeling and Measurements and Their Source Control Implications 10/10/1999
Bullock, O R. Mercury Modeling and Measurements and Their Source Control Implications. Presented at 1999 POP and Heavy Metals Workshop, Durham, NC, October 10-11, 1999.
Abstract: There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.

PRESENTATION U.S. EPA Models-3/Cmaq Status and Applications 10/04/1999
Schere, K L. U.S. EPA Models-3/Cmaq Status and Applications. Presented at US/German Ozone/Fine Particle Science and Environmental Chamber Workshop, Riverside, CA, October 4-6, 1999.
Abstract: An advanced third-generation air quality modeling system has been developed by the Atmospheric Modeling Division of the U.S. EPA. The air quality simulation model at the heart of the system is known as the Community Multiscale Air Quality (CMAQ) Model. It is comprehensive in scope and allows for the simulation of ozone and photochemical oxidants, acid deposition, and fine and coarse particles at spatial scales ranging from urban to regional. The model is contained within a computational framework, Models-3 (for 3rd generation), that enables users to interact with the modeling system through a high-level graphical user interface and also facilitates data transmission among the components of the system and provides for analysis, graphics, and visualization capabilities for model simulation results. The modeling system is available from the U.S. EPA (see web site: www.epa.gov/asmdnerl/models3/), and is currently being evaluated for photochemical oxidants and fine particles using field study databases from the eastern United States from 1990 and 1995. The CMAQ is also being extended to include the modeling of selected air toxics, including atmospheric mercury and atrazine (a pesticide).
Models-3 is a sophisticated computational framework for air quality modeling systems. It has been designed and programmed using object-oriented principles (in C++ language). At the highest level, Models-3 presents a graphical user interface (GUI) to the model user. Components presented include the Program and Dataset Managers, for registering programs and datasets; Science Manager and Model Builder for defining science process components and building an executable model, Study Planner for defining and running the required preprocessors and models, Strategy manager for defining emission control strategies and processing emissions, and Tools Manager which is the gateway to the analysis and visualization tools. Models-3 assists the user in setting up new model domains and applications, accessing and tracking data files, and controlling the flow of data and model runs. Component models may be run on the same computer platform as Models-3, or on remote computers where communications links are maintained to the Models-3 server. A configuration currently used at the U.S. EPA has the Models-3 server maintained on a SUN workstation with CMAQ model runs initiated on remote CRAY supercomputers linked to the workstation through fast telecommunication lines.

The most recent release of the Models-3 framework is compatible with SUN workstations

PRESENTATION One-Atmosphere Dynamics Description in the Models-3 Community Multi-Scale Quality (Cmaq) Modeling System 07/27/1999
Byun, D W. One-Atmosphere Dynamics Description in the Models-3 Community Multi-Scale Quality (Cmaq) Modeling System. Presented at Air Pollution 99, Seventh International Conference, San Francisco, CA, July 27-29, 1999.
Abstract: This paper proposes a general procedure to link meteorological data with air quality models, such as U.S. EPA's Models-3 Community Multi-scale Air Quality (CMAQ) modeling system. CMAQ is intended to be used for studying multi-scale (urban and regional) and multi-pollutant (ozone, aerosol, and acid/nutrient depositions) air quality problems. The Models-3 CMAQ system is expected to be a common vehicle to advance environmental modeling techniques for scientist and the regulatory community. To provide multi-scale capability for meteorological and air quality modeling, a set of governing equations for the fully compressible atmosphere is introduced. By recasting input meteorological data with the variables that satisfy the governing equations in a generalized coordinate system, CMAQ can follow the dynamics and thermodynamics of the meteorological model closely. A robust mass conservation scheme is introduced and discussed.

PRESENTATION Aermod: Model Formulation and Evaluation Results 06/20/1999
Paine, R. J., R. F. Lee, R. W. Brode, R. Wilson, A. J. Cimorelli, S G. Perry, J. C. Weil, A. Venkatram, AND W. P. Peters. Aermod: Model Formulation and Evaluation Results. Presented at Proceedings of the 92nd Annual Meeting of the Air & Waste Management Association, St. Louis, MO, June 20-24, 1999.
Abstract: AERMOD is an advanced plume model that incorporates updated treatments of the boundary layer theory, understanding of turbulence and dispersion, and includes handling of terrain interactions. This paper presents an overview of AERMOD's features relative to ISCST3.
AERMOD has been evaluated on 10 databases, which include flat and hilly terrain areas, urban and rural sites, and a mixture of tracer experiments as well as routing monitoring networks with a limited number of fixed monitoring sites. This paper presents a summary of the evaluation results of AERMOD with these diverse databases.

PRESENTATION Overview of the Ozark Isoprene Experiment (Ozie) 06/20/1999
Pierce Jr., T E., M. Koerber, A. Guenther, S. King, S. Lingerich, AND J. Turner. Overview of the Ozark Isoprene Experiment (Ozie). Presented at 92nd Annual Meeting of the Air and Waste Management Association, St. Louis, MO, June 20-24, 1999.
Abstract: Ozone modeling studies, such as those performed for the Ozone Transport Advisory Group (OTAG), have raised concerns about extremely high isoprene concentrations (. 50ppbv) that have been predicted over the Ozark Plateau in southern Missouri. In response to these concerns, a collaborative study was undertaken involving participants from AMEREN, U.S. Department of Army at Fort Leonard Wood, Lake Michigan Air Directors Consortium, National Center for Atmospheric Research, Perdue University, U.S. Environmental Protection Agency, Washington State University, Washington University (St. Louis), and the states of Illinois, Indiana, and Missouri. The Ozark Isoprene Experiment (OZIE) took place during July 1998 and included measurements of isoprene from the surface and aloft at several locations stretching from northeastern Oklahoma to southern Indiana. Measurements were made along a balloon tethered to nearly 1000 m, surface footprint sites at five locations upwind of the balloon, surface sites in Illinois and Indiana, and from an aircraft flying at heights ranging from 300 to 1000 m over southern Illinois, southern Indiana, and souther Missouri. Preliminary analysis of the data indicates that daytime surface isoprene concentrations ranged from 0.4 to 6 ppbv. Conditions were favorable for the emission of isoprene, with daytime maximum temperatures exceeding 32 C on at least four days during the two-week study period. This paper provides an overview of the study design and describes measurements taken during the experiment.

PRESENTATION Modeling Assessment of Transport and Deposition Patterns of Mercury Air Emissions from the U.S. and Canada 05/23/1999
Bullock, O R. Modeling Assessment of Transport and Deposition Patterns of Mercury Air Emissions from the U.S. and Canada. Presented at 5th International Conference on Mercury as a Global Pollutant, Rio de Janeiro, Brazil, May 23-28, 1999.
Abstract: In December 1997, the U.S. EPA submitted the Mercury Study Report to Congress which included a regional-scale modeling assessment of the transport and deposition of U.S. air emissions of mercury. This modeling was performed with a modified version of the Regional Lagrangian Model of Air Pollution (RELMAP). Canadian mercury emissions data were not obtained in time to be included in the simulations described in the report to the U.S. Congress. Thus, reported comparisons of deposition modeling results to observed values in the northern portions of the continental U.S. were of limited scientific value. An inventory of Canadian air emissions of mercury was obtained in late 1997 from Environment Canada which has now been included in a new RELMAP simulation of annual mercury deposition patterns.
These new Canadian emissions data have been simulated using the same version of the RELMAP and the same estimates of source-dependent emission speciation as were used for U.S. emissions in the previous study. New mercury wet deposition modeling results obtained using both U.S. and Canadian emission inventories have been compared with observed values in various locations within the continental U.S. These new modeling results have also been compared to the previously reported results from U.S. emissions only to obtain a rough bi-national apportionment of mercury deposition across the continental U.S. and southern Canada.

Preliminary modeling results show that the addition of the Canadian emissions inventory data increases RELMAP simulated wet deposition by 20% or more in only a few areas of the U.S. immediately adjacent to the Canadian border. The locations for which observed wet deposition data were compared to modeling results in the Mercury Study Report to Congress were not significantly affected by the Canadian emissions to the simulation. Conversely, a rather large area of Canada north of the Great Lakes and in the Maritime Provinces does appear to have a significant portion of simulated mercury wet deposition attributable to U.S. sources.

Eulerian modeling frameworks are now being developed at the U.S. EPA and other research organizations to more accurately treat global-scale and upper atmospheric transportable mercury. However, comparison of these new modeling results with long-term observations of wet deposition shows that the simpler Lagrangian framework of the RELMAP is capable of simulating regional-scale cross-boundary transport of mercury to very useful scientific accuracies of about 40% over most of the U.S. and Canada.

PRESENTATION Impact of Secular Precipitation Changes on the Deposition of Benzo[a]pyrene to the Neuse River Basin of North Carolina 01/19/1999
Cooter, E J., J B. Hill, AND Y. Cohen. Impact of Secular Precipitation Changes on the Deposition of Benzo[a]pyrene to the Neuse River Basin of North Carolina. 11th Conference on Applied Climatology, Dallas, TX, January 10-15, 1999.
Abstract: There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.

PRESENTATION Sharing Resources Through Collaboration Using Technology 01/13/1999
PooleKober, E M. Sharing Resources Through Collaboration Using Technology. Presented at Second Annual Meeting of the Atmospheric Sciences Librarians International, Dallas, TX, January 13-15, 1999.
Abstract: In response to changing social and economic conditions, instant communication, emerging technology, and decreasing resources for libraries, there is a need for librarians to use collaborative methods, strategies, and technologies to solve common problems or produce common products. For effective collaboration, librarians must identify goals and expected outcomes and express an interest in collaborating with those who share them. With the emergence of new collaborative tools, together with older technology, librarians have an opportunity to put together teams to foster productive relationships and reach goals and expected outcomes in a most satisfactory manner. This paper will focus on some of the available collaborative technologies, and advantages of collaboration.

PRESENTATION Modeling Stomatal Response to Atmospheric Humidity 01/10/1999
Pleim, J E. Modeling Stomatal Response to Atmospheric Humidity. Presented at 13th Conference on Boundary Layers and Turbulence, 79th AMS Annual Meeting, Dallas, TX, January 10-15, 1999.
Abstract: There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.

PUBLISHED REPORT System Installation and Operation Manual for the EPA Third-Generation Air Quality Modeling System (Models-3) Version 3.0 11/09/1999
Atmospheric Modeling Division, AND EPA Systems Development Center. System Installation and Operation Manual for the EPA Third-Generation Air Quality Modeling System (Models-3) Version 3.0. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-99/057 (NTIS PB2000-101617), 1999.
Abstract: Models-3 is a flexible software system designed to simplify the development and use of environmental assessment and other decision support tools. It is designed for applications ranging from regulatory and policy analysis to understanding the complex interactions of atmospheric chemistry and physics. The June 1999 release of Models-3 contains a Community Multiscale Air Quality (CMAQ) modeling system for urban to regional scale air quality simulation of tropospheric ozone, acid deposition, visibility, and fine particles. Principal improvements since the initial release in June 1998 include the availability of a full port of Models-3 to Windows-NT based computers. This Installation and Operations Manual includes an overview of the system architecture, installation requirements, procedures for installation of the Models-3 server and clients, establishing users, Models-3 system start-up and shut-down, loading of data sets, description of system administration functions, and installation examples.

PUBLISHED REPORT Documentation for the Gridded Hourly Atrazine Emissions Data Set for the Lake Michigan Mass Balance Study: A Final Contract Report 10/12/1999
Scholtz, M. T., B. J. VanHeyst, AND A. Ivanoff. Documentation for the Gridded Hourly Atrazine Emissions Data Set for the Lake Michigan Mass Balance Study: A Final Contract Report. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-99/067 (NTIS PB99-175416), 1999.
Abstract: In order to develop effective strategies for toxics management, the Great Lakes National Program Office (GLNPO) of the United States Environmental Protection Agency (U.S. EPA), in 1994, launched an ambitious five year program to conduct a mass balance study of selected toxics pollutants in Lake Michigan for the target year of 1995 (U.S. EPA, 1998). Three persistent organic pollutants (POPs) and one heavy metal have been selected for the focus of the Lake Michigan Mass Balance (LMMB) study: polychlorinated biphenyls (PCBs), trans-nonachlor, atrazine and mercury.
Atrazine is a broadleaf herbicide typically applied to corn, sorghum, sugarcane, pastures, sweet corn, seed crops and sod (Gianessi and Puffer, 1991). In 1991, applications to corn and sorghum accounted for approximately 95% of the total atrazine usage in the United States (Gianessi and Puffer, 1991). Atrazine is typically applied as a pre-emergent spray and/or a post-emergent spray although it an also be incorporated into the soil prior to planting (USDA, 1995a). Peer reviewed literature suggests that atmospheric sources of atrazine may be an important input of herbicide to the Lake Michigan system (Schottler and Eisenreich, 1997). The National Oceanic and Atmospheric Administration (NOAA) is collaborating with the LMMB study in its estimation of the atmospheric deposition of atrazine to Lake Michigan.

PUBLISHED REPORT Using Mm5 Version 2 With Cmaq and Models-3, a User's Guide and Tutorial 08/20/1999
Otte, T L. Using Mm5 Version 2 With Cmaq and Models-3, a User's Guide and Tutorial. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-99/065 (NTIS PB99-175424), 1999.
Abstract: Meteorological data are important in many of the processes simulated in the Community Multi-Scale Air Quality (CMAQ) model and the Models-3 framework. The first meteorology model that has been selected and evaluated with CMAQ is the Fifth-Generation Pennsylvania State University/National Center for Atmospheric Research (NCAR) Mesoscale Model (MM5). All software in the Penn State/NCAR mesoscale modeling system has been dedicated to the public domain and is presently used for both research and operational purposes at many organizations worldwide. Other meteorological models are being considered for compatibility with CMAQ but are not available at this time.
This document is a basic overview of MM5 and its relationship with CMAQ and Models-3. Some general information is provided to help the user get started with MM5 in preparation for Models-3 and CMAQ,, and it is meant to supplement NCAR's official documentation on MM5.

PUBLISHED REPORT User Manual for the EPA Third-Generation Air Quality Modeling System (Models-3 Version 3.0) 07/20/1999
Atmospheric Modeling Division, AND EPA Systems Development Center. User Manual for the EPA Third-Generation Air Quality Modeling System (Models-3 Version 3.0). U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-99/055 (NTIS PB2000-100247), 1999.
Abstract: Models-3 is a flexible software system designed to simplify the development and use of environmental assessment and other decision support tools. It is designed for applications ranging from regulatory and policy analysis to understanding the complex interactions of atmospheric chemistry and physics. The June 1999 release of Models-3 contains a Community Multiscale Air Quality (CMAQ) modeling system for urban to regional scale air quality simulation of tropospheric ozone, acid deposition, visibility, and fine particles. Principal improvements since the initial release in June 1998 include improve particulate modeling capability in CMAQ, modeling of particulate emissions from vehicles as part of emission data processing, improved flexibility in assigning parameters from meteorological models to vertical layers, and the availability of a full port of Models-3 to Windows-NT based computers. Models-3 and CMAQ in combination form a powerful third generation air quality modeling and assessment system that enables a user to execute air quality simulation models and visualize their results. Models-3/CMAQ also assists the model developer to assemble, test, and evaluate science process components and their impact on chemistry-transport model predictions by facilitating the interchange of science codes, transparent use of multiple computing platforms, and access of data across the network. The Models-3/CMAQ provides flexibility to change key model specifications such as grid resolution and chemistry mechanisms without rewriting the code. Models-3/CMAQ is intended to serve as a community framework for continual advancement and use of environmental assessment tools. This User Manual serves as a reference on how to use the software system. Companion documents detail the installation procedures and provide a step-by-step tutorial, and describe the scientific algorithms.

PUBLISHED REPORT Local and Regional Contributions of Fine Particulate Mass to Urban Areas in the Mid-Atlantic and Southwestern US 05/10/1999
Schichtel, B. D. Local and Regional Contributions of Fine Particulate Mass to Urban Areas in the Mid-Atlantic and Southwestern US. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-99/036 (NTIS PB99-147209), 1999.
Abstract: There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.

PUBLISHED REPORT EPA Third-Generation Air Quality Modeling System, Models-3 Volume 9c: User Manual Standard Tutorial 04/09/1999
Novak, J H. AND et al. EPA Third-Generation Air Quality Modeling System, Models-3 Volume 9c: User Manual Standard Tutorial. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-98/069(c) (NTIS PB99-139180), 1999.
Abstract: There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.

PUBLISHED REPORT Science Algorithms of the EPA Models-3 Community Multiscale Air Quality (Cmaq) Modeling System 03/01/1999
Byun, D W. AND J.K S. Ching. Science Algorithms of the EPA Models-3 Community Multiscale Air Quality (Cmaq) Modeling System. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/R-99/030 (NTIS PB2000-100561), 1999.
Abstract: There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.

 

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