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Atmospheric Modeling Division Publications: 2004
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This page lists publication titles, citations and abstracts produced by NERL's Atmospheric Modeling Division for the year 2004, organized by Publication Type. Your search has returned
112 Matching Entries.
See also Atmospheric Modeling Division citations with abstracts:
1999,
2000,
2001,
2002,
2003,
2004,
2005,
2006,
2007,
2008
Technical Information Manager: Liz Hope - (919) 541-2785 or hope.elizabeth@epa.gov
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Presented/Published |
| BOOK CHAPTER |
Modeling Wind Erosion and Dust Emission on Vegetated Surfaces |
05/01/2004
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OKIN, G. S. AND D. GILLETTE. Modeling Wind Erosion and Dust Emission on Vegetated Surfaces. Chapter 7, Spatial Modellling of the Terrestrial Environment. John Wiley and Sons, LTD, , Uk, 137-156, (2004).
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Understanding and predicting the behaviour of natural and human environmental systems is crucial for the effective management of the Earth's limited resources.
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| EPA PUBLISHED PROCEEDINGS |
An Approach to a Unified Process-Based Regional Emission Flux Modeling Platform |
06/07/2004
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Benjey, W. G. AND T. E. Pierce Jr. An Approach to a Unified Process-Based Regional Emission Flux Modeling Platform. 13th Annual Emission Inventory Conference. EPA/600/R-06/020 (NTIS PB2006-106647), 2004.
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The trend towards episodic modeling of environmentally-dependent emissions is increasing, with models available or under development for dust, ammonia, biogenic volatile organic compounds, soil nitrous oxide, pesticides, sea salt, and chloride, mercury, and wildfire emissions. These emissions are estimated as hourly values using numerical modeling from physical principles, resulting in more realistic values than the historic al approach of using national annual air quality inventories with temporal and spatial disaggregation factors. The basis of many of these new modeling tools is a surface flux model, either one-way or bi-directional, underpinned by similar surface boundary physics, with modifications or parameters to treat the flux of a specific emission compound or class of emissions. These developments will result in closely-related emission modeling tools with overlapping input data requirements. The emission flux models will need to be installed in or coupled to an emission modeling system, such as the Sparse Matrix Operator Kernel emission (SMOKE) system. To maintain a unified one-atmosphere approach to air quality modeling, and to ensure a consistent scientific basis and computational efficiency, a unified emission flux modeling approach capable of estimating all or most of the environmentally-dependent emissions is recommended. This can be accomplished by establishing a model platform containing representations of the basic chemical and physical mechanisms for mass fluxes of gaseous and particulate emissions. The modeled emissions will be merged by SMOKE with reported emission data from an inventory and supplied to the Community Multiscale Air Quality (CMAQ) model, a regional Eulerian grid model. In some instances, modeling of bi-directional fluxes will be necessary, which may require a closer coupling with CMAQ to accommodate reinitialization of the concentration field at each time step.
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.
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| JOURNAL |
Innovative Methods for Emission Inventory Development and Evaluation: Workshop Synthesis |
11/01/2004
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Hidy, G. M., J. D. Mobley, AND S. Cadle. Innovative Methods for Emission Inventory Development and Evaluation: Workshop Synthesis. , 11/01/2004. EM: AIR AND WASTE MANAGEMENT ASSOCIATIONS MAGAZINE FOR ENVIRONMENTAL MANAGERS. Air & Waste Management Association, Pittsburgh, PA, 31-34, (2004).
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Emission inventories are key databases for evaluating, managing, and regulating air pollutants. Refinements and innovations in instruments that measure air pollutants, models that calculate emissions, and techniques for data management and uncertainty assessment are critical to enhancing the emission inventory. To facilitate improvement in emissions inventories, communication and increased cooperation between developers and users are essential. The 2003 NARSTO/CEC Workshop, Innovative Methods for Emission Inventory Development and Evaluation, provided recommendations for improving emission factors, improving emission models, and reducing inventory uncertainty along with improving communication among emission inventory developers and users along with policy makers and data analysts. Emission inventories that incorporate these recommendations will have an increased probability of meeting the challenges of the future.
Any views expressed by the authors do not necessarily reflect the views of the US Environmental Protection Agency, General Motors, NARSTO, CEC or those of the governments of Canada, Mexico, and the United States. It has been subjected to Agency review and approved for publication.
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| JOURNAL |
Primary and Secondary Organic Aerosols Over the United States: Estimates on the Basis of Observed Organic Carbon (Oc) and Elemental Carbon (Ec), and Air Quality Modeled Primary (Oc/Ec) Ratios |
10/01/2004
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Yu, S., R. L. Dennis, P. BHAVE, AND B. K. Eder. Primary and Secondary Organic Aerosols Over the United States: Estimates on the Basis of Observed Organic Carbon (Oc) and Elemental Carbon (Ec), and Air Quality Modeled Primary (Oc/Ec) Ratios. ATMOSPHERIC ENVIRONMENT 38(31):5257-5268, (2004).
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The temporal and spatial distributions of primary and secondary organic carbon aerosols (OC) over the continental US during June 15 to August 31, 1999, were estimated by using observational OC and elemental carbon (EC) data from Interagency Monitoring of Protected Visual Environments (IMPROVE) and Southeastern Aerosol Research and Characterization project (SEARCH) networks, coupled with the primary OC/EC ratios, (OC/EC)pri, obtained from an emission/transport-model (i.e., US EPA Models-3/Community Multiscale Air Quality (CMAQ) model). It was found that the mean primary OC concentrations over the Northeast, Southeast, Central, West and West Pacific regions were 0.39 +/-0.09 (mean standard deviation), 1.02 +/-0.55, 0.47+/- 0.34, 0.51+/-0.24, and 0.96 +/-0.68 ug C m-3, respectively, while the mean secondary OC concentrations were 1.27 +/-0.15, 1.52+/-0.59, 0.90+/- 0.51, 0.51+/- 0.29, and 0.94+/-0.52 ug C m-3, respectively. The contribution of secondary OC to the measured OC ranged from 48 +/-16% over the West to 77 +/-3% over the Northeast. The mean values of modeled (OC/EC)pri ratios ranged from 1.16 +/-0.13 over the Northeast to 3.49 +/-1.22 over the West Pacific. The results at the SEARCH sites indicate that the daily mean values of modeled (OC/EC)pri ratios ranged from 0.84 to 2.99 at Yorkville and the contributions of secondary OC to OC ranged from 0% to 66% at North Birmingham. Our results indicate significant temporal and geographic variability in the relative contributions of primary and secondary OC and that the use of a constant value to represent the (OC/EC)pri ratio at a location is not appropriate over the time scales studied here.
The United States Environmental Protection Agency through its Office of Research and Development funded and managed the research described here. It has been subjected to Agency's administrative review and approved for publication.
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| JOURNAL |
Mechanisms of Convection-Induced Modulation of Passive Tracer Interhemispheric Transport Interannual Variability |
07/01/2004
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Lintner, B. R., A. B. Gilliland, AND I. Y. Fung. Mechanisms of Convection-Induced Modulation of Passive Tracer Interhemispheric Transport Interannual Variability. JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 109(7):1-13, (2004).
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Interannual variations of tropical convection impact atmospheric circulation and influence year-to-year variations of the transport of trace constituents in the troposphere. This study examines how two modes of convective variability-anomalous intensification and meridional displacement of centers of tropical convection-impact interhemispheric transport (IHT) interannual variability. Two modeling frameworks are employed-an atmospheric general circulation model (AGCM) and a chemical transport model (CTM) forced with a realistic, interannually-varying circulation field-to investigate the zonally-averaged and regional-scale influences of the modes of convective variability on passive tracer IHT. Both convective modes are found to modulate IHT interannual variability. While convective displacement appears to be the more quantitatively significant mode within the AGCM framework, anomalous convective intensity and displacement are of equal importance in the CTM framework. The results suggest that the modeling of atmospheric tracer transport interannual variability requires accurate representation of multiple aspects of convective variability.
The United States Environmental Protection Agency through its Office of Research and Development collaborated in the research described here. It has been subjected to Agency review and approved for publication.
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| JOURNAL |
Innovative Methods for Emission-Inventory Development and Evaluation: Workshop Summary |
11/01/2004
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Mobley, J. D. AND S. Cadle. Innovative Methods for Emission-Inventory Development and Evaluation: Workshop Summary. JOURNAL OF THE AIR AND WASTE MANAGEMENT ASSOCIATION. Air & Waste Management Association, Pittsburgh, PA, 1422-1439, (2004).
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Emission inventories are an essential tool for evaluating, managing, and regulating air pollution. Refinements and innovations in instruments that measure air pollutants, models that calculate emissions as well as techniques for data management and uncertainty assessment are needed to enhance emission inventories. This Workshop provided recommendations for improving emission factors, improving emission models, and reducing inventory uncertainty. Communication to increase cooperation between developers and users of inventories is essential. Emission inventories that incorporate these improvements will meet the challenges of the future.
Any views expressed by authors do not necessarily reflect the views of the US Environmental Protection Agency, General Motors, NARSTO, CEC or those of the governments of Canada, Mexico, and the United States.
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| JOURNAL |
An Objective Climatology of Carolina Coastal Fronts |
08/01/2004
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APPEL, W., A. J. RIORDAN, AND T. A. HOLLEY. An Objective Climatology of Carolina Coastal Fronts. AMERICAN METEROLOGICAL SOCIETY. Plenum Press, New York, NY, 20(4):439-455, (2004).
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This study describes a simple objective method to identify cases of coastal frontogenesis offshore of the
Carolinas and to characterize the sensible weather associated with frontal passage at measurement sites
near the coast. The identification method, based on surface hourly data from offshore and adjacent land
stations, was applied to an 11-yr dataset (1984–94). A total of 379 coastal fronts was found, 70 of which
eventually made landfall along the North Carolina coast; 112 that remained offshore, and 197 were termed diurnal since they remained offshore but disappeared during daylight hours. Results show that most coastal and offshore sites experience a wind shift of about 40°–70° and a warming of about 2°–3°C during the hour of frontal passage. Exceptions include sites near colder waters where the rates are markedly reduced and frontal passage is often less discernible. Excluding diurnal fronts, just over half the cases were associated with cold-air damming (CAD) during the cold season of 16 October–15 April. Most of these winter cases linked with CAD were onshore fronts. During the warm season, most fronts were diurnal, but the association with CAD was still significant. To explore the synoptic-scale environment, composite maps for the cold season were generated for all three frontal subtypes from NCEP–NCAR reanalysis data. Results show a strong surface anticyclone centered north of the region of frontogenesis for all three composites. However, several features in the
synoptic-scale regimes appear to differentiate the three frontal types. For example, cyclogenesis in the Gulf
of Mexico and onshore southeasterly low-level flow along the southeast Atlantic coast accompanied by warm advection distinguish onshore fronts from the other two types. The offshore fronts are accompanied by more nearly zonal flow aloft and a surface anticyclone that stalls near the New England coastline. Finally, the diurnal type is associated with much weaker pressure and height fields and an east–west elongated surface anticyclone centered much farther south than in the other cases.
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| JOURNAL |
Modeling Air Pollution from the Collapse of the World Trade Center and Assessing the Potential Impacts on Human Exposure |
02/01/2004
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HUBER, A. H., P. GEORGOPOULOS, R. GILLIAM, G. STENCHIKOV, S. WANG, B. KELLY, AND H. FEINGERSH. Modeling Air Pollution from the Collapse of the World Trade Center and Assessing the Potential Impacts on Human Exposure. EM: AIR AND WASTE MANAGEMENT ASSOCIATIONS MAGAZINE FOR ENVIRONMENTAL MANAGERS. Air & Waste Management Association, Pittsburgh, PA, 35-40, (2004).
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The US EPA National Exposure Research Laboratory (NERL) and the Environmental and Occupational Health Sciences Institute (EOHSI) have been working together under a University Partnership Agreement to develop improved methods for human exposure modeling. This partnership was ongoing prior to September 11, 2001 but has since directed part of its efforts to support EPA assessment studies of potential human exposures following the collapses of the twin towers and the fires that burned at the site of the World Trade Center. The scope of the modeling reported in this paper has three principal modeling topics: a) meteorology and pollutant plume in the Metropolitan NY area and impact on downwind locations, b) fine-scale pollution impact in the local area of lower Manhattan South of Canal Street, and c) human exposure assessment to ambient pollution. Also, a wind tunnel model study of was conducted to support understanding of fine-scale pollution in the urban street canyons of lower Manhattan is reported in a separate paper. Additional research and application development will continue as part of the total effort, and will be reported as it is developed and projects completed. The collapse of the World Trade Center (WTC) towers increased the awareness that there are scientific shortcomings when it is necessary to do exposure modeling of air pollution events in urban environments and in being able to provide timely modeling support. The scientific shortcoming is most serious when the air pollution events occur in an urban center where the understanding of airflow around large buildings is poor. The larger purpose of ongoing modeling developments and applications is to work to provide demonstrated the tools for future application in support of the Program and Regional Offices at EPA.
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| JOURNAL |
Sub-Canopy Deposition of Ozone in a Stand of Cutleaf Cornflower |
09/01/2004
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FINKELSTEIN, P. L., A. W. DAVIDSON, H. S. NEUFELD, T. MEYERS, AND A. H. CHAPPELKA. Sub-Canopy Deposition of Ozone in a Stand of Cutleaf Cornflower. ENVIRONMENTAL POLLUTION. Elsevier Science Ltd, New York, NY, 131(2):295-303, (2004).
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Although there has been a great deal of research on ozone, interest in exposure of native, herbaceous species is relatively recent and it is still not clear what role the pollutant has in their ecological fitness. The ozone exposure of a plant is usually expressed in terms of the concentration above the canopy or as a time-weighted index. However, to understand the physiological effects of ozone it is necessary to quantify the ozone flux to individual leaves as they develop, which requires knowing the deposition velocity and concentration of the pollutant as a function of height throughout the plant canopy. We used a high-order closure model of subcanopy turbulence to estimate ozone profiles in stands of cutleaf coneflower (Rudbeckia laciniata L.) located in the Great Smoky Mountains National Park, USA. The model was run for periods coinciding with a short field study, during which we measured vertical concentration profiles of ozone along with measurements of atmospheric turbulence and other meteorological and plant variables. Predictions of ozone profiles by the model are compared with observations throughout the canopy.
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| JOURNAL |
Wind Tunnel Simulation of Flow and Pollutant Dispersal Around the World Trade Center Site |
02/01/2004
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PERRY, S. G., D. HEIST, R. S. THOMPSON, W. H. SNYDER, AND R. E. LAWSON. Wind Tunnel Simulation of Flow and Pollutant Dispersal Around the World Trade Center Site. EM: AIR AND WASTE MANAGEMENT ASSOCIATIONS MAGAZINE FOR ENVIRONMENTAL MANAGERS. Air & Waste Management Association, Pittsburgh, PA, 31-34, (2004).
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The U.S. Environmental Protection Agency's (EPA) mission to protect human health and the environment has also been directed to include homeland security (i.e., to emphasize and expand its expertise and capability to prevent, where possible, and to detect and respond to, where necessary, accidental and intentional releases of toxic substances into the environment). Since numerical simulation models are important tools for assessing and responding to these types of releases, there is an ongoing need for both field and laboratory studies for model-development and model-evaluation purposes.
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| JOURNAL |
A Combined Modeling and Measurement Technique for Estimating Wind-Blown Dust Emissions at Owens (Dry) Lake, Ca |
01/07/2004
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GILLETTE, D., D. ONE, AND K. RICHMOND. A Combined Modeling and Measurement Technique for Estimating Wind-Blown Dust Emissions at Owens (Dry) Lake, Ca. JOURNAL OF GEOPHYSICAL RESEARCH. American Geophysical Union, Washington, DC, 109(F01003):1-23, (2004).
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A refined method of modeling atmospheric dust concentrations due to wind erosion was developed using real-time saltation flux measurements and ambient dust monitoring data at Owens Lake, California. This modeling method may have practical applications for modeling the atmospheric effects of wind erosion in other areas. Windblown dust from the Owens Lake bed often causes violations of federal air quality standards for particulate matter (PM10) that are the highest levels measured in the United States. The goal of this study was to locate dust source areas on the exposed lake bed, estimate their PM10 emissions, and use air pollution modeling techniques to determine which areas caused or contributed to air quality violations.
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| JOURNAL |
Deposition and Removal of Fugitive Dust in the Arid Southwestern United States: Measurements and Model Results |
09/01/2004
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ETYEMEZIAN, V., S. AHONEN, D. NIKOLIC, J. GILLIES, H. KUHNS, D. GILLETTE, AND J. VERANTH. Deposition and Removal of Fugitive Dust in the Arid Southwestern United States: Measurements and Model Results. JOURNAL OF AIR AND WASTE MANAGEMENT. Air & Waste Management Association, Pittsburgh, PA, 54(9):1099-1113, (2004).
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This work was motivated by the need to better reconcile emission factors for fugitive dust with the amount of geologic material found on ambient filter samples. The deposition of particulate matter with aerodynamic diameter less than or equal to 10 µm (PM10), generated by travel over an unpaved road, over the first 100 m of transport downwind of the road was examined at Ft. Bliss, near El Paso, TX.
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| JOURNAL |
A "TEST of Concept" Comparison of Aerodynamic and Mechanical Resuspension Mechanisms for Particles Deposited on Field Rye Grass (Secale Cercele). Part I. Relative Particle Flux Rates |
09/04/2004
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GILLETTE, D., R. E. LAWSON, AND R. S. THOMPSON. A "TEST of Concept" Comparison of Aerodynamic and Mechanical Resuspension Mechanisms for Particles Deposited on Field Rye Grass (Secale Cercele). Part I. Relative Particle Flux Rates. ATMOSPHERIC ENVIRONMENT. Elsevier Science Ltd, New York, NY, 38(28):4789-4797, (2004).
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Resuspension of uniform latex micro spheres deposited on a single seed pod of field rye grass stalk and head was investigated experimentally in a wind tunnel. The experiment was designed to distinguish aerodynamic (viscous and turbulent) mechanisms from mechanical resuspension resulting from the oscillatory impact of the grass hitting a stationary object.
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A "TEST of Concept" Comparison of Aerodynamic and Mechanical Resuspension Mechanisms for Particles Deposited on Field Rye Grass (Secals Cercele). Part 2. Threshold Mechanical Energies for Resuspension Particle Fluxes |
09/01/2004
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GILLETTE, D., R. E. LAWSON, AND R. S. THOMPSON. A "TEST of Concept" Comparison of Aerodynamic and Mechanical Resuspension Mechanisms for Particles Deposited on Field Rye Grass (Secals Cercele). Part 2. Threshold Mechanical Energies for Resuspension Particle Fluxes. ATMOSPHERIC ENVIRONMENT. Elsevier Science Ltd, New York, NY, 38(28):4799-4803, (2004).
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Kinetic energy from the oscillatory impacts of the grass stalk against a stationary object was measured with a kinetic energy measuring device. These energy inputs were measured as part of a resuspension experiment of uniform latex microspheres deposited on a single rye grass seed pod in a wind tunnel. The experiment was designed to measure resuspension from aerodynamic (viscous and turbulent) mechanisms compared to that from mechanisms from mechanical resuspension resulting from the oscillatory impact of the grass hitting a stationary object. The experiment was run for deposited spherical latex particles with diameters from 2 to 8.1 µm. Wind tunnel tests were run for wind speeds from 2 to 18.5 ms -1 and a turbulence intensity (root-mean-square fluctuation wind speed/mean wind speed) of 0.1.
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| PRESENTATION |
The US Mercury Emission Inventory for the Arctic Council Action Plan |
06/08/2004
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Rackley, K., A. Pope, J. D. Mobley, S. Durkee, AND M. Engle. The US Mercury Emission Inventory for the Arctic Council Action Plan. Presented at International Emission Inventory Conference, Clearwater, FL, June 07 - 10, 2004.
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The Arctic Council, having agreed to act to reduce exposures to a number of priority pollutants in the Arctic region, has initiated a mercury project via the Arctic Council Action Plan (ACAP). The project is led by the Danish EPA with a Steering Group from all eight Arctic countries-Canada, Denmark, Finland, Iceland, Norway, Russia, Sweden, and United States. The overall project objective is to contribute to a decrease of mercury releases from Arctic countries. This will be accomplished partly by contributing to the development of a common regional framework for an action plan or strategy for the decrease of mercury emissions, and partly by evaluating and selecting one or a few specific point sources for implementation of control measures. It is felt that the decrease of mercury releases from key sources should serve as a demonstration of existing possibilities, giving inspiration to other control measures in the region.
One of the first steps in the action plan is the development of an inventory of mercury releases to the land, air, and water. Characterization of mercury usage and its disposition will provide the framework for an action plan and strategy for decreasing the amount of mercury in the environment. A detailed questionnaire was developed to collect consistent data from the involved countries, including key information on modeling parameters (e.g., latitude/longitude, stack parameters, chemical composition, and emissions control technology).
EPA completed the U.S. portion of the questionnaire to provide data and information to the project. All data sources are publicly available and most are from EPA inventories, e.g., National Emissions Inventory (NEI) for air emissions and Toxics Release Inventory (TRI) for solid waste disposal and water discharges. The results characterize the mobilization of mercury in the US to the land, air, and water. The overwhelming mobilization action is land disposal associated with gold mining. The most significant air source category is coal combustion. Other sources of air emissions include gold mining, chlor-alkali plants, municipal waste combustors, medical waste incinerators, and industrial boilers. There were minimal discharges to water bodies noted from the data available.
The ACAP project should result in availability of data to enable assessment of mercury issues in the Arctic and is expected to be a model for international data exchange on mercury and other pollutants. The overall project is intended to identify research opportunities for engineering demonstrations that provide scientific information on mercury control options in the Arctic and around the world.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Development of Cfd Simulation Applications for Local-Scale Areas and Potential Interface With Mesoscale Models |
01/11/2004
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Huber, A. H. Development of Cfd Simulation Applications for Local-Scale Areas and Potential Interface With Mesoscale Models. Presented at Workshop on Mergng Mesoscale & Computational Fluid Dymanics, Seattle, WA, January 11, 2004.
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The presentation summarizes developments of ongoing applications of fine-scale (geometry specific) CFD simulations to urban areas within atmospheric boundary layers. Enabling technology today and challenges for the future are discussed. There is a challenging need to develop a two-way interface between these simulations with mesoscale model applications on a course scale (not CFD geometry specific). The key element of CFD simulations is their ability to simulate the precise effects of specific geometry. The steps in setting up a CFD model is reviewed through an example of buildings in lower Manhattan. CFD simulation can be applied both to resolve fine-scale air dispersion when it is desirable and as a base to develop parameterization for a course-scale mesoscale model. CFD models are being evaluated through comparisons with wind tunnel model and field study data. Present studies and developments are being used to develop standard practice and identify how best to improve computational efficiencies.
The U.S. Environmental Protection Agency through its Office of Research and Development funded the research described here. It is subjected to Agency review. Mention of trade names or commercial products does not constitute an endorsement or recommendation for use.
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| PRESENTATION |
Nonstationary Spatial Modeling of Environmental Data Using a Process Convolution Approach |
08/11/2004
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Swall, J. L. Nonstationary Spatial Modeling of Environmental Data Using a Process Convolution Approach. Presented at 2004 Joint Statistical Meeting, Toronto, Ontario, Canada, August 8-12, 2004.
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Traditional approaches to modeling spatial processes involve the specification of the covariance structure of the field. Although such methods are straightforward to understand and effective in some situations, there are often problems in incorporating non-stationarity and in manipulating the large covariance matrices that result when dealing with large datasets. Our approach takes a different perspective, modeling a process as a convolution of a Gaussian white noise process and suitable kernels. Depending on the particular parameterization, this approach can allow flexibility in modeling non-stationary processes, while avoiding the task of working directly with the covariance matrix. In this talk, we discuss some relevant approaches, and present an application involving environmental monitoring. In particular, we focus on such practical issues as computational efficiency and methods for assimilating data from differing sources.
This is an abstract of a proposed presentation and does not necessarily reflect the United States Environmental Protection Agency (EPA) policy. The actual presentation has not been peer reviewed by EPA. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
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| PRESENTATION |
Postprocessing Model Output for Comparison to Ambient Data |
02/10/2004
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Bhave, P. Postprocessing Model Output for Comparison to Ambient Data. Presented at PM Model Performance Workshop, Chapel Hill, NC, February 10, 2004.
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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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| PRESENTATION |
Noaa/EPA Air Quality Model Forecast System |
02/11/2004
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Pleim, J. A. Noaa/EPA Air Quality Model Forecast System. Presented at Environment Canada Air Quality Forecast Training, Halifax, Nova Scotia, February 11, 2004.
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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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| PRESENTATION |
Time-Resolved and in-Depth Evaluation of PM and PM Precursors Using Cmaq |
02/10/2004
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Dennis, R. L. Time-Resolved and in-Depth Evaluation of PM and PM Precursors Using Cmaq. Presented at PM Model Performance Workshop, Research Triangle Park, NC, February 10-11, 2004.
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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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| PRESENTATION |
EPA High End Computing Activities: Coordinating Group Briefing |
03/19/2004
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Walter, G. EPA High End Computing Activities: Coordinating Group Briefing. Presented at National Information Technology Research & Development, Washington, DC, March 19, 2004.
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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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| PRESENTATION |
Narsto Emission Inventory Workshop & Assessment |
01/15/2004
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Mobley, J. D. Narsto Emission Inventory Workshop & Assessment. Presented at CENR Air Quality Research Committee, Washington, DC, January 15, 2004.
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This presentation summarizes the NARSTO activities related to emission inventories in 2003-2005. The NARSTO Particulate Matter Assessment, issued in 2003, identified emission inventories as one of the critical elements of the air quality program which needs improvement if it is to meet expectations of the program. Accordingly, NARSTO arranged a Workshop on Innovative Methods for Emission Inventory Development and Evaluation which was held in Austin, Texas on October 14-17, 2003. The findings from the Workshop are summarized. In addition, NARSTO has embarked on an assessment of emission inventory activities to determine what enhancements are needed to enable emission inventories to deliver improved products with the desired quality, timeliness, and cost. The schedule, budget, and plans for the assessment are outlined. Through these efforts, the NARSTO community hopes to improve the emission inventories that are available in US, Canada, and Mexico such that air quality management programs in North America can achieve their air quality goals and emission inventories can support their role the process.
This is an abstract of a proposed presentation and does not necessarily reflect the United States Environmental Protection Agency (EPA) policy. The actual presentation has not been peer reviewed by EPA. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
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| PRESENTATION |
Using Air Quality Models for Emissions Management Decisions, Making Decisions in the Face of Uncertainty |
03/18/2004
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Rao, S. T. Using Air Quality Models for Emissions Management Decisions, Making Decisions in the Face of Uncertainty. Presented at Presentation to NRC Committee on CREM, Washington, DC, March 18, 2004.
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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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| PRESENTATION |
Integrated Use of Observations and Model Outputs in Air Quality Management |
03/24/2004
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Rao, S. T. Integrated Use of Observations and Model Outputs in Air Quality Management. Presented at Presentation Third Canadian Workshop on Air Quality, Quebec City, Quebec, Canada, March 24, 2004.
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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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| PRESENTATION |
Evaluation of 3-D Regional Models: Measurement Needs for Inorganic Species |
04/21/2004
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Dennis, R. L. Evaluation of 3-D Regional Models: Measurement Needs for Inorganic Species. Presented at EMEP Workshop on Particulate Matter Measurement & Modeling, New Orleans, LA, April 20-23, 2004.
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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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| PRESENTATION |
An Annual Evaluation of Models-3 Cmaq Using a 2001 Simulation |
04/22/2004
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Eder, B. K., S. Yu, R. L. Dennis, A. B. Gilliland, S. Howard, AND A. Torian. An Annual Evaluation of Models-3 Cmaq Using a 2001 Simulation. Presented at EMEP Workshop on Particulate Matter Measurement & Modeling, New Orleans, LA, April 20-23, 2004.
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| Abstract:
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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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| PRESENTATION |
Comparison of Cmaq and Aerosol Optical Depths from Satellites |
05/04/2004
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Roy, B. AND A. B. Gilliland. Comparison of Cmaq and Aerosol Optical Depths from Satellites. Presented at Workshop on Air Quality Applications of Satellite Data, Washington, DC, May 4, 2004.
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| Abstract:
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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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| PRESENTATION |
Measurement Needs for Evaluating Model Calculations for Carbonaceous Aerosol |
04/22/2004
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Bhave, P. Measurement Needs for Evaluating Model Calculations for Carbonaceous Aerosol. Presented at EMEP Workshop on Particulate Matter Measurement & Modeling, New Orleans, LA, April 20-23, 2004.
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| Abstract:
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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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| PRESENTATION |
Aqueous Reduction of Hg2+ to Hg0 By Ho2 in the Cmaq-Model |
07/02/2004
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Bullock, O. R. Aqueous Reduction of Hg2+ to Hg0 By Ho2 in the Cmaq-Model. Presented at International Conference on Mercury as a Global Pollutant, Ljubljana, Slovinia, June 27-July 2, 2004.
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| Abstract:
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Numerical models of atmospheric mercury are formulated based on the current understanding of mercury chemistry in air and in atmospheric water. Recent evidence that significant reduction of Hg2+ by reaction with HO2 may not actually occur in natural atmospheric water has obvious implications for the modeling of atmospheric mercury, the seriousness of which has been investigated in the context of the Community Multi-scale Air Quality (CMAQ) model. A published rate constant of 1.1x10 4 M-1s-1 for the aqueous reduction of Hg2+ by HO2 was used in the mercury version of the CMAQ model (CMAQ-Hg) that was previously tested for its agreement to observed measurements of mercury wet deposition in the United States. A modeling analysis has now been conducted to investigate the effect of removing this controversial reaction from the CMAQ-Hg model. The results show more mercury wet deposition, thus reducing the low bias previously found from the base model configuration. However, other sources for this low bias have also been identified. An examination of mercury concentrations in precipitation brings into question the apparent model improvement and highlights the need for confident determination of chemical kinetic modeling parameters.
The information in this document has been funded wholly or in part by the U.S. Environmental Protection Agency (EPA and has been developed as part of an interagency agreement with the National Oceanic and Atmospheric Administration (NOAA). It has been subjected to review by both EPA and NOAA, and has been approved for publication, although it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Aqueous Reduction of Hg2+ to Hg0 By Ho2 in the Cmaq Model |
07/02/2004
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Bullock, O. R. Aqueous Reduction of Hg2+ to Hg0 By Ho2 in the Cmaq Model. Presented at International Conference on Mercury as a Global Pollutant, Ljubljana, Slovenia, June 27-July 2, 2004.
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| Abstract:
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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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| PRESENTATION |
Atmospheric Modeling of Air Pollutants With the Community Multiscale Air Quality (Cmaq) Model |
06/03/2004
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Schere, K. L. Atmospheric Modeling of Air Pollutants With the Community Multiscale Air Quality (Cmaq) Model. Presented at EPA Science Forum 2004, Washington, DC, June 1-4, 2004.
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| Abstract:
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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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| PRESENTATION |
Narsto Emission Inventory Assessment |
06/02/2004
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Mobley, J. D., S. Cadle, M. Deslauriers, H. Feldman, C. Frey, L. RojasBracho, AND S. Wierman. Narsto Emission Inventory Assessment. Presented at EPA Science Forum 2004, Washington, DC, June 1-3, 2004.
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The NARSTO Emission Inventory Committee has been pursuing enhancement of the emission inventory program for North American countries--Canada, Mexico, and the United States. With the completion of the NARSTO Ozone and Particulate Matter Assessments, it was recognized that emission inventories are critical to the success of air quality management programs and that emissions inventories need improvement to meet the expectations for quality, timeliness, and cost effectiveness. Accordingly, NARSTO sponsored a workshop to address new and innovative methods for emission inventory development and evaluation. Findings and recommendations from the workshop led NARSTO to undertake an assessment of the emission inventory programs across North America. The assessment, slated for completion in 2005, includes identifying what emission inventory programs are needed for the 21st century, recognizing the capabilities and limitations of current programs, and recommending enhancements needed to move the programs forward to be successful in the future.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Introduction of Urban Canopy Parameterization Into Mm5 to Simulate Urban Meteorology at Neighborhood Scale |
01/13/2004
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Dupont, S., J. S. Ching, AND S. Burian. Introduction of Urban Canopy Parameterization Into Mm5 to Simulate Urban Meteorology at Neighborhood Scale. Presented at American Meteorological Society, Seattle, WA, January 11-15, 2004.
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| Abstract:
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Since most of the primary atmospheric pollutants are emitted inside the roughness sub-layer (RSL) and consequently the first chemical reactions and dispersion occur in this layer, it is necessary to generate detailed meteorological fields inside the RSL to perform air quality modeling at high spatial resolutions. At neighborhood scale (on order of 1-km horizontal grid spacing), the meteorological fields are strongly influenced by the presence of the vegetation and building morphology of varying complexity, which requires developing more detailed treatment of the influence of canopy structures in the models and using additional morphological databases as input. The assumptions of the roughness approach, used by most of the mesoscale models, are unsatisfactory at this scale. Hence, a detailed urban and rural canopy parameterization (Dupont et al., 2003c), called DA-SM2-U, has been developed inside the Penn State/NCAR Mesoscale Model (MM5) to simulate the meteorological fields within and above the urban and rural canopies. DA-SM2-U uses the drag-force approach to represent the dynamic and turbulent effects of the buildings and vegetation, and a modified version of the soil model SM2-U (Dupont et al., 2003a and b), called SM2-U(3D), to represent the thermodynamic effects of the canopy elements. A first evaluation of DA-SM2-U on the city of Philadelphia (USA) (Dupont et al., 2003c) with a simple urban morphology representation has shown that the model is capable of simulating the important features observed in the urban and rural areas.
The improvement of the urban canopy representation in mesoscale models requires the knowledge of more parameters. These parameters can be divided into three categories: i) the empirical parameters which are deduced from calibration of the models; ii) the "material parameters" which correspond to the physical properties of the surface materials of the canopy elements, they can be easily found in the literature from tables; and iii) the morphological parameters which depend on the structure and on the 3D arrangement of the canopy elements (buildings, vegetation, etc). The morphological parameters are variable from one city to another, and need to be averaged on few 100-m2 with a vertical resolution of a couple meters to be used at neighborhood scales. Thus, these parameters may be the most difficult parameters to estimate.
Here, the DA-SM2-U version of MM5 is applied to Houston, Texas (USA), in order to study the influence of the morphological parameter resolution on the meteorological fields to know if a detailed resolution of these parameters is required or not for simulating at neighborhood scales. To provide the most accurate representation of these morphological parameters for the entire MM5 computational domain, a Houston GIS Urban Database has been created. This paper gives a brief description of the DA-SM2-U model and of the procedures used to create the morphological parameters on Houston. The first results of the influence study of the representation of the city of Houston on the structure of the urban boundary layer are presented.
This paper has been reviewed in accordance with United States Environmental Protection Agency's peer and administrative review policies and approved for presentation and publication.
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| PRESENTATION |
Air Quality Modeling at Coarse-to-Fine Scales in Urban Areas |
01/13/2004
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Ching, J. S., S. Dupont, J. Herwehe, T. L. Otte, A. Lacser, D. W. Byun, AND R. Tang. Air Quality Modeling at Coarse-to-Fine Scales in Urban Areas. Presented at Conference on Atmospheric Chemistry: Air Quality in Megacities, Seattle, WA, January 11-15, 2004.
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Urban air toxics control strategies are moving towards a community based modeling approach, with an emphasis on assessing those areas that experience high air toxic concentration levels, the so-called "hot spots". This approach will require information that accurately maps and characterizes the spatial and temporal variability of pollutants. Many air toxic pollutants are active in photochemistry and their ambient concentration levels will depend on the magnitude of the secondary products from the inflow regional background as well as from fresh emissions. In principle, the Community Multi-scale Air Quality (CMAQ) modeling system, using multi-scale modeling attributes can provide the ambient concentrations of air toxics from both regional and local sources and through advanced treatment of chemical, transport and deposition pathways. This paper explores the CMAQ capability to model air toxics at fine scale to meet the desired air toxics assessments objectives.
This paper has been reviewed in accordance with United States Environmental Protection Agency's peer and administrative review policies and approved for presentation and publication.
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| PRESENTATION |
Use of Pilot Study Monitoring Data to Help Evaluate An Air Quality Model (Cmaq) for Toxic Air Pollutants |
06/03/2004
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Luecken, D. J. AND W. T. Hutzell. Use of Pilot Study Monitoring Data to Help Evaluate An Air Quality Model (Cmaq) for Toxic Air Pollutants. Presented at Air Toxics Data Analysis Workshop, Chicago, IL, June 2-3, 2004.
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| Abstract:
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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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| PRESENTATION |
Review of Ammonia Emission Modeling Techniques for Natural Landscapes and Fertilized Soil |
06/09/2004
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Battye, W., R. Barrows, AND T. E. Pierce Jr. Review of Ammonia Emission Modeling Techniques for Natural Landscapes and Fertilized Soil. Presented at 13th Annual Emission Inventory Conference, Clearwater, FL, June 7-10, 2004.
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| Abstract:
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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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| PRESENTATION |
Wind Tunnel Products: Air Flow Patterns and Pollutant Dispersions in Complex Urban Areas |
06/02/2004
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Bowker, G. Wind Tunnel Products: Air Flow Patterns and Pollutant Dispersions in Complex Urban Areas. Presented at EPA Science Forum 2004, Washington, DC, June 1-3, 2004.
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| Abstract:
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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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| PRESENTATION |
Modeling Atmospheric Mercury in Continental Air Masses |
05/25/2004
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Bullock, O. R. Modeling Atmospheric Mercury in Continental Air Masses. Presented at International Workshop on Harmonization of Mercury Measurements Methods & Models to Assess Source-Receptors Impact on Air Quality & Human Health, Maratea, Italy, May 23-26, 2004.
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| Abstract:
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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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| PRESENTATION |
Evidence of Enhanced Vertical Dispersion in the Wakes of Tall Buildings in Wind Tunnel Simulations of Lower Manhattan |
08/25/2004
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Heist, D. K., S. G. Perry, AND G. Bowker. Evidence of Enhanced Vertical Dispersion in the Wakes of Tall Buildings in Wind Tunnel Simulations of Lower Manhattan. Presented at 5th Symposium on the Urban Environment, Vancouver, British Columbia, Canada, August 23-27, 2004.
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Observations of flow and dispersion in urban areas with tall buildings have revealed a phenomenon whereby contaminants can be transported vertically up the lee sides of tall buildings due to the vertical flow in the wake of the building. This phenomenon, which contributes to what is sometimes called "rapid vertical dispersion", has important consequences for the dispersion of pollutants in urban areas and its understanding may be crucial to improving urban dispersion models. This venting effect was observed in a wind-tunnel study of dispersion from the site of the destroyed World Trade Center (WTC) in New York City, using a scale model of lower Manhattan, including a scaled representation of the rubble pile.
Enhanced vertical dispersion was seen on the downwind side of several tall buildings in the highly urban area surrounding the WTC site using a smoke tracer. The flow responsible for this vertical dispersion was measured with laser Doppler velocimetry, and its effects on the plume were demonstrated with concentration measurements of an ethane tracer released from the rubble pile. Notably, the World Financial Center buildings, which stood upwind of the WTC site for westerly winds, caused an initial vertical dispersion of the plume before it began to move downward. This vertical dispersion was caused by a vertical flow in the wake of these buildings and resulted in rapid transport of contaminants to heights above the building tops. The enhancement of the dispersion of the WTC plume due to tall building wake effects is analyzed and compared with Gaussian plume model predictions.
Although this work was reviewed by EPA and approved for publication it may not necessarily reflect Agency policy.
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| PRESENTATION |
A Comparison of Airflow Patterns from the Quic Model and An Atmospheric Wind Tunnel for a Two-Dimensional Building Array and a Multi-City Block Region Near the World Trade Center Site |
08/25/2004
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Bowker, G., S. G. Perry, AND D. K. Heist. A Comparison of Airflow Patterns from the Quic Model and An Atmospheric Wind Tunnel for a Two-Dimensional Building Array and a Multi-City Block Region Near the World Trade Center Site. Presented at 5th Symposium on the Urban Environment, Vancouver, British Columbia, Canada, August 23-27, 2004.
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Dispersion of pollutants in densely populated urban areas is a research area of clear importance. Currently, few numerical tools exist capable of describing airflow and dispersion patterns in these complex regions in a time efficient manner. (QUIC), Quick Urban & Industrial Complex, a fast-running flow and dispersion simulation program has shown promise is this area. QUIC flow patterns were compared against two wind tunnel data sets, namely: one for a simple two-dimensional building array; another for a complex group of buildings surrounding the World Trade Center in lower Manhattan. In both cases QUIC satisfactorily simulated the flow patterns depicting channeling and recirculation patterns within particular street canyons.
This paper has been reviewed in accordance with the United States Environmental Protection Agency's peer and administrative review policies and approved for presentation and publication.
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| PRESENTATION |
High-Resolution Dataset of Urban Canopy Parameters for Houston, Texas |
08/24/2004
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Burian, S., S. W. Stetson, W. Han, J. S. Ching, AND D. W. Byun. High-Resolution Dataset of Urban Canopy Parameters for Houston, Texas. Presented at 5th Symposium on the Urban Environment, Vancouver, BC, Canada, August 23-27, 2004.
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Urban dispersion and air quality simulation models applied at various horizontal scales require different levels of fidelity for specifying the characteristics of the underlying surfaces. As the modeling scales approach the neighborhood level (~1 km horizontal grid spacing), the representation of urban morphological structures requires much greater detail. To provide the most accurate surface characterization possible for an air quality modeling study of Houston, Texas, airborne LIDAR (Light Detection and Ranging) data were obtained from TerraPoint LLC at 1-m horizontal grid cell spacing for Harris County, Texas, an area of approximately 5800 km2. The data were managed in a GIS software package and scripts and codes were written in Avenue, VBA, and Fortran to compute 20 urban canopy parameters (UCPs) including building height statistics and histograms, height-to-width ratio, plan area density function, frontal area density function, roughness length, displacement height, mean orientation of streets, and sky view factor. In addition, procedures were developed to approximate several UCPs that could not be determined from the LIDAR elevation data, including surface cover type, building material fraction, and percent directly connected impervious area. In this paper, we describe the Houston dataset derivation techniques and results, report on correlations of the UCPs to land use, population, and other nationally consistent datasets, as well as reporting on the accuracy of methods to extrapolate UCPs to outlying areas of the city where high-resolution full-feature terrain datasets are not available.
This paper has been reviewed in accordance with the United States Environmental Protection Agency's peer and administrative review policies and approved for presentation and publication.
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| PRESENTATION |
Linking Air Toxic Concentrations from Cmaq to the Hapem5 Exposure Model at Neighorhood Scales for the Philadelphia Area |
08/24/2004
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Ching, J. S., T. E. Pierce Jr., T. Palma, W. T. Hutzell, R. Tang, A. Cimorelli, AND J. Herwehe. Linking Air Toxic Concentrations from Cmaq to the Hapem5 Exposure Model at Neighorhood Scales for the Philadelphia Area. Presented at 5th Symposium on the Urban Environment, Vancouver, BC, Canada, August 23-27, 2004.
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This paper provides a preliminary demonstration of the EPA neighborhood scale modeling paradigm for air toxics by linking concentration from the Community Multi-scale Air Quality (CMAQ) modeling system to the fifth version of the Hazardous Pollutant Exposure Model (HAPEM5). For this demonstration, annual simulations of CMAQ are performed at multiple scales at 36, 12, and 4 km grid sizes. The domain for 36 km size included the continental U. S., while the smaller grid sizes included nexted domains that encompassed Philadelphia and the state of Delaware. In this application, specific air toxics species were defined and added to the Carbon Bond-IV mechanism. HAPEM5 allowed for the introduction of temporal and spatial (sub-grid)varibilities. Temporal variability was estimated using hourly outputs for a year at each grid cell. The sub-grid variability was estimated using customized software designed to provide gridded Probability Density Functions (PDFs) to describe the concentration distributions from running the Gaussian dispersion model ISC in fine receptor mode. This application demonstrates that a more robust set of information can be gathered for HAPEN5 than by applying the ISC approach. For example, this methodology provides considerably larger dynamic range of temporal and spatial variability not available using ISC alone. Moreover, using CMAQ allows for more accurate estimation of secondary species such as formaldehyde and acetaldehyde, which are not treated explicitly in models such as ISC.
Although this work was reviewed by EPA and approved for publication it may not necessarily reflect official agency policy
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| PRESENTATION |
Neighborhood Scale Air Quality Modeling in Houston Using Urban Canopy Parameters in Mm5 and Cmaq With Improved Characterization of Mesoscale Lake-Land Breeze Circulation |
08/24/2004
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Ching, J. S., S. Dupont, R. Gilliam, S. Burian, AND R. Tang. Neighborhood Scale Air Quality Modeling in Houston Using Urban Canopy Parameters in Mm5 and Cmaq With Improved Characterization of Mesoscale Lake-Land Breeze Circulation. Presented at 5th Symposium of Urban Environment, Vancouver, BC, Canada, August 23-27, 2004.
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Advanced capability of air quality simulation models towards accurate performance at finer scales will be needed for such models to serve as tools for performing exposure and risk assessments in urban areas. It is recognized that the impact of urban features such as street and tree canopies will become more pronounced as the grid sizes decreases. This paper will focus on methods to introduce urban features into a predictive model to provide accurate and representative temporal and spatial resolve meteorological fields for running the Community Multiscale Air Quality (CMAQ) modeling system at neighborhood scales (order 1 km grid resolution).
A set of urban canopy parameters (UCP) have been derived for a 1 km grid mesh for a modeling domain encompassing Harris County and surrounding areas. This set of gridded UCPs was specifically developed for implementation of the DA-SM2-U/MM5 system (Dupont, et al., 2004); specifically, a canopy drag approach was developed for incorporation into an advanced urbanized surface layer (soil-atmosphere) model (SM2-U) which was further implemented into the NCAR-Penn State Mesoscale Meteorological Model, Version 5 (MM5). A total of 23 UCP (combination of vertical profiles and surface values) were derived from a database consisting of buildings and vegetation features from airborne lidar measurements, ancillary data from satellites, high altitude photography, as well as detailed residential, commercial and industrial maps.
This paper examines results from two sets of CMAQ simulations each driven by MM5 at 1 km grid size, one with this specialized set of UCPs and the other using the standard version. Preparatory to this, it is recognized that the pollutant transport in the Houston area will be strongly affected by the sea and Galveston Bay breezes (Gilliam et al., 2004); thus, care is taken to ensure the accuracy of the modeled circulation induced by Galveston Bay. Introducing gridded inputs (showing relatively large diurnal amplitude) of the sea surface temperature (SST) of Galveston Bay) from observations taken from polar orbiting satellite platforms resulted in greatly improved accuracy of the MM5 land-bay breeze circulation simulations at 4 km grid resolution. It will be demonstrated that the 1 km grid size simulations are sensitive to the degree of accuracy of the input boundary condition of the flow field from the coarser 4 km grid nest. The resulting implications for the finer scale simulations with UCP on the flow and the subsequent air quality fields will be presented and discussed.
This paper has been reviewed in accordance with the United States Environmental Protection Agency's peer and administrative review policies and approved for presentation and publication.
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| PRESENTATION |
A Program of Developments Supporting the Applications of Cfd Simulations of Micrometeorology and Pollution Transport Within Urban Building Environments |
07/15/2004
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Huber, A. H. AND M. Lazaro. A Program of Developments Supporting the Applications of Cfd Simulations of Micrometeorology and Pollution Transport Within Urban Building Environments. Presented at 8th Annual George Mason University Transport & Dispersion Modeling Conference, Fairfax, VA, July 13-15, 2004.
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| Abstract:
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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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| PRESENTATION |
Cfd Modeling of Fine Scale Flow and Transport in the Houston Metropolitan Area, Texas |
08/25/2004
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Lee, S., H. S. Fernando, D. W. Byun, AND J. S. Ching. Cfd Modeling of Fine Scale Flow and Transport in the Houston Metropolitan Area, Texas. Presented at 5th Symposium on the Urban Environment, Vancouver, BC, Canada, August 23-27, 2004.
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| Abstract:
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Fine scale modeling of flows and air quality in Houston, Texas is being performed; the use of computational fluid dynamics (CFD) modeling is being applied to investigate the influence of morphologic structures on the within-grid transport and dispersion of sources in grid models with grid sizes of order 1 km. This study provides a basis for examining, understanding and eventually leading to improving parameterizations of sub-grid variability in the concentration fields for air pollutants and/or toxic agents. Several cells of 1 km size are chosen in different parts of Houston, Texas that contain different characteristic mix of urban morphologic structures (e.g., buildings, street canyons, tree canopies, paved areas) for this study. One key aspect of this investigation will be to examine the consequences of utilizing various input background meteorological forcing to the CFD simulations. Typically, one assumes arbitrary background flow, which may not be representative of the actual flow at the specific grid cell. This study will examine input meteorology from model outputs from an urbanized form of MM5 at 1 km grid resolution, but implemented an advanced urban module called DA-SM2U (Dupont et al., 2004). This module requires an advanced set of urban canopy parameters, UCPs, gridded at 1 km resolution, which have been developed using the same set of detailed, high (order 1 m) resolution data for the CFD study for provide full measure of consistency. For examining sensitivity, these CFD results will be contrasted against the use of other inputs meteorology such as (a) using standard version of MM5, and (b) airport observations.
This paper has been reviewed in accordance with the United States Environmental Protection Agency's peer and administrative review policies and approved for presentation and publication.
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| PRESENTATION |
Quantifying Subgrid Pollutant Variability in Eulerian Air Quality Models |
08/25/2004
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Herwehe, J., J. S. Ching, AND J. L. Swall. Quantifying Subgrid Pollutant Variability in Eulerian Air Quality Models. Presented at 5th Symposium on the Urban Environment, Vancouver, BC, Canada, August 23-27, 2004.
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| Abstract:
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In order to properly assess human risk due to exposure to hazardous air pollutants or air toxics, detailed information is needed on the location and magnitude of ambient air toxic concentrations. Regional scale Eulerian air quality models are typically limited to relatively coarse grid resolutions when simulating mean pollutant concentrations for each grid cell volume, and subgrid pollutant extremes are not represented. Continual improvements in computing power and refinement of nested grid techniques have allowed the regional air quality models to simulate down to grid spacings on the order of one kilometer. Concurrent developments in neighborhood scale modeling using computational fluid dynamics (CFD) and coupled large-eddy simulation (LES) with photochemistry techniques have permitted simulations with grid spacings of meters to tens of meters for domains limited to several kilometers. Our goal is to develop a methodology to utilize available fine resolution gridded model results to produce statistical analyses of pollutant subgrid variability applicable to the coarser grid resolutions, thereby somewhat bridging the gap between regional scale and neighborhood scale air quality models.
Exploratory data analysis (EDA) statistical techniques are being employed in the development of a post-processing software tool which systematically analyzes fine resolution gridded model results in order to objectively determine best-fit univariate distributions representing subgrid pollutant concentration variability. Specific probability density functions (pdfs) for the selected distributions are then produced, which can subsequently be used as input data for hazardous air pollutant human exposure models.
Initial application of the pdf analysis software has been on fine resolution results from a Community Multiscale Air Quality (CMAQ) modeling system urban case study. Statistical analyses of selected trace gas concentrations from both an urban and a rural area will be compared. Additional analyses applied to the entire model domain will illustrate how the derived distributions vary spatially. As expected, the fitted pdfs are shown to be functions of pollutant, time, location, and overall meteorological-photochemical scenario characteristics. The potential for creating improved parameterizations of subgrid pollutant variability will be explored based on the fields of pdfs and their associated location, variation, and/or shape parameters. This new pollutant subgrid variability analysis package can be applied to any data set, whether originating from air quality model output or monitoring network observations.
Although this work was reviewed by NOAA and EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Cmaq New Release Overview |
07/21/2004
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Pleim, J. A. Cmaq New Release Overview. Presented at CMAQ Internet Session, Research Triangle Park, NC, July 21, 2004.
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| Abstract:
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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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| PRESENTATION |
A New Non-Local Boundary Layer Model |
07/23/2004
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Pleim, J. A. A New Non-Local Boundary Layer Model. Presented at WRF/MM5 User's Workshop & WRF Tutorial, Boulder, CO, June 22-25, 2004.
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| Abstract:
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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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| PRESENTATION |
Urban Morphological Analysis for Mesoscale Meteorological and Dispersion Modeling Applications: Current Issues |
08/25/2004
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Burian, S., M. J. Brown, J. S. Ching, M. L. Cheuk, M. Yuan, W. Han, AND A. T. McKinnon. Urban Morphological Analysis for Mesoscale Meteorological and Dispersion Modeling Applications: Current Issues. Presented at 5th Symposium on the Urban Environment, Vancouver, BC, Canada, August 23-27, 2004.
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| Abstract:
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Representing urban terrain characteristics in mesoscale meteorological and dispersion models is critical to produce accurate predictions of wind flow and temperature fields, air quality, and contaminant transport. A key component of the urban terrain representation is the characterization of the morphology of cities. This can be accomplished using 3D building and vegetation databases containing extent and height information in concert with remotely sensed data to calculate a set of morphological and surface cover parameters. Currently, morphological and surface cover parameters are unknown quantities for most locations and their values must be estimated using intuition and best guesses. In extreme cases, the necessary high resolution data for small areas is available and this information can be used to extrapolate to larger areas or areas where data is not available. However, the task of computing the parameters is time consuming and rife with uncertainties. Fundamental guidance on the necessary data resolution and the effect of aggregation is not well defined. Nor is the appropriate means established to correlate parameters to underlying nationally consistent datasets and account for parameter variability within a city and between cities when performing extrapolation. This paper will report on the analysis of urban canopy parameters computed for eight cities in the U.S. The results will focus on the variability of the parameters within each city and between cities. Results will also be reported for an assessment of data resolution effects aggregation procedures when aggregating from dataset resolution to modeling grid cell resolution.
The United States Environmental Protection Agency through its Office of Research and Development also partially funded and collaborated in the work described here. It has been subjected to Agency review and approved for publication.
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| PRESENTATION |
Comparison of Sulfate Concentrations Simulated By Two Regional-Scale Models With Measurements from the Improve Network |
06/03/2004
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Irwin, J. S., E. L. Gego, C. Hogrefe, J. M. Jones, AND S. T. Rao. Comparison of Sulfate Concentrations Simulated By Two Regional-Scale Models With Measurements from the Improve Network. Presented at 9th Harmonization Conference, Garmisch-Kartenkirchen, Germany, June 1-4, 2004.
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| Abstract:
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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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| PRESENTATION |
Comparisons of Spatial Patterns of Wet Deposition to Model Predictions |
09/22/2004
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Finkelstein, P. L. Comparisons of Spatial Patterns of Wet Deposition to Model Predictions. Presented at NADP 2004 Scientific Symposium and Technical Committee Meeting, Halifax, Nova Scotia, September 21-24, 2004.
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| Abstract:
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The Community Multiscale Air Quality model, (CMAQ), is a "one-atmosphere" model, in that it uses a consistent set of chemical reactions and physical principles to predict concentrations of primary pollutants, photochemical smog, and fine aerosols, as well as wet and dry deposition. The model is being used to develop new federal regulations, state implementation plans, and air quality forecasts. As a part of a comprehensive evaluation of CMAQ, this study compares the spatial prediction of yearly total wet deposition of sulfate, nitrate, and ammonium across the country to measurements made by NADP. In order to develop spatial maps of wet deposition it is necessary to interpolate between monitoring sites. However it has been shown that rainfall fields are very spatially discontinuous and non-stationary. Therefore, spatial interpolation of wet deposition is problematic. To overcome this obstacle others have proposed using spatially interpolated precipitation-weighted concentration of the pollutant in rainfall along with a more detailed rainfall field derived from the more dense rainfall networks. We take that idea a step further, by considering two possible sources of data. One is a recently available National Precipitation Analysis. This dataset has been developed by NOAA's National Center for Environmental Prediction with the Office of Hydrology. The analysis merges two data sources, 3000 automated raingage observations with the digital precipitation estimates from the WSR-88D weather radar. The radar bias is corrected using the gage network. The results are generated onto a 4 km grid. For this analysis, the grid has been relaxed to 36 km to match it to the CMAQ grid. The other precipitation source is the NOAA cooperative observer network, with more than 6000 sites in the lower 48 states. The paper will discuss the advantages and disadvantages of these precipitation datasets. The NADP concentration measurements are interpolated to the same grid as the precipitation using a statistical model. Deposition is computed at each cell. The computed spatial fields of total deposition for sulfate, nitrate and ammonium are then compared to the CMAQ model output, and the similarities and differences are noted. Consideration is given to model biases caused by inaccurate precipitation inputs to the model as well as inherent model biases.
Although this work was reviewed by EPA and approved for publication, it may or may not necessarily reflect official Agency policy at this time .
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| PRESENTATION |
Updates and Evaluation of the Community Multiscale Air Quality (Cmaq) Model 2004 Release |
08/25/2004
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Pleim, J. A. Updates and Evaluation of the Community Multiscale Air Quality (Cmaq) Model 2004 Release. Presented at 13th Joint Conference on the Applications of Air Pollution Meteorology with the Air and Waste Management Association, Vancouver, BC, Canada, August 23-27, 2004.
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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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| PRESENTATION |
Development and Applications of Cfd Simulations in Support of Air Quality Studies Involving Buildings |
08/24/2004
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Huber, A. H., W. Tang, A. Flowe, B. Bell, K. H. Kuehlert, AND W. Schwarz. Development and Applications of Cfd Simulations in Support of Air Quality Studies Involving Buildings. Presented at 13th Joint Conference on the Applications of Air Pollution Meteorology with the Air Waste Management Association, Vancouver, BC, Canada, August 23-27, 2004.
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There is a need to properly develop the application of Computational Fluid Dynamics (CFD) methods in support of air quality studies involving pollution sources near buildings at industrial sites. CFD models are emerging as a promising technology for such assessments, in part due to the advancing power of computational hardware and software. CFD simulations have the potential to yield more accurate solutions than other methodologies because they use a solution of the fundamental physics equations and include the effects of detailed three-dimensional geometry and local environmental conditions. However, the tools are not well validated for environmental modeling and best-practice methodologies have not been established. Fluent, Inc and the US EPA National Exposure Research Laboratory are working cooperatively to help make CFD a proven and applied tool in support of environmental assessment studies.
The results of CFD simulations can both be directly used to better understand specific case studies as well as be used to support the development of more-simplified algorithms that may be generally applied. Unlike most currently used regulatory air quality models, CFD simulations are able to include specific details of building structures as well as a range of defined atmospheric turbulent boundary layers. Plume dispersion in the absence of buildings are demonstrated to be comparable with standard plume dispersion models for point and line source pollutant emissions. Boundary layer turbulence is being simulated as characterized by surface roughness (characterized by u*) and surface heat flux (characterized by Obukhov length L).
This paper discusses ongoing development and application of CFD simulations through case studies using CFD software for simulating air pollutant concentrations from sources near buildings. Comparisons of CFD simulations to reference wind tunnel data and field measurement studies are presented to provide model performance evaluation/validation. An example comparison of the vertical wind component is shown in the following figure for flow over an array of 2-dimensional block buildings. This is one of several evaluation studies that will be presented. In addition to model evaluation/validation there is a need to identify the most efficient set-up for CFD simulations characterized by selection of grid size, turbulence models and other critical operational parameters. A report on progress for developing best practice methods for CFD applications in support of air quality studies involving buildings is presented.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
A Test of Thermodynamic Equilibrium Models and 3-D Air Quality Models for Predictions of Aerosol No3 -{ |
10/26/2004
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Yu, S., R. L. Dennis, S. J. Roselle, A. Nenes, J. Walker, B. K. Eder, K. L. Schere, J. L. Swall, AND W. P. Robarge. A Test of Thermodynamic Equilibrium Models and 3-D Air Quality Models for Predictions of Aerosol No3 -{. Presented at 27th NATO/CCMS International Technical Meeting on Air Pollution Modeling and its Application, Banff, AB, CANADA, October 25 - 29, 2004.
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The inorganic species of sulfate, nitrate and ammonium constitute a major fraction of atmospheric aerosols. The behavior of nitrate is one of the most intriguing aspects of inorganic atmospheric aerosols because particulate nitrate concentrations depend not only on the amount of gas phase nitric acid, but also on the availability of ammonia and sulfate, together with temperature and relative humidity. Particulate nitrate is produced mainly from the equilibrium reaction between two gas phase species, HNO3 and NH3.
It is a very challenging task to partition the semi-volatile inorganic aerosol components between the gas and aerosol phases correctly. The normalized mean error (NME) for predictions of nitrate is typically three times that for predictions of sulfate for a variety of 3 D air quality models applied to sections of the U.S. (Odman, et al., 2002; Pun, et al, 2004). For an annual average across the entire U.S. the NMEs of the predictions of nitrate from the U.S. EPA Models 3/Community Multiscale Air Quality Model (CMAQ) are two to three times larger than the NMEs for sulfate.
The research presented here was performed under the Memorandum of Understanding between the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) and under agreement number DW13921548. Although it has been reviewed by EPA and NOAA and approved for publication, it does not necessarily reflect their policies or views.
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| PRESENTATION |
An Operational Evaluation of the Eta-Cmaq Air Quality Forecast Model |
10/27/2004
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Kang, D., B. K. Eder, R. Mathur, S. Yu, AND K. L. Schere. An Operational Evaluation of the Eta-Cmaq Air Quality Forecast Model. Presented at 27th NATO/CCMS International Technical Meeting on Air Pollution Monitoring and Its Applications, Banff, Alberta, Canada, October 25-29, 2004.
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The National Oceanic and Atmospheric Administration (NOAA), in collaboration with the Environmental Protection Agency (EPA), are developing an Air Quality Forecasting Program that will eventually result in an operational Nationwide Air Quality Forecasting System. The initial phase of this program, which couples NOAA's Eta meteorological model with EPA's Community Multi-scale Air Quality (CMAQ) model, began operation in May of this year and has been providing forecasts of hourly, maximum 1- and 8-hour ozone concentrations over the northeastern United States.
As part of this initial phase, an operational evaluation of the coupled modeling system is being performed in which both discrete forecasts (observed versus modeled concentrations) for hourly, maximum 1-hr, and maximum 8-hr O3 concentrations and categorical forecasts (observed versus modeled exceedances / non-exceedances) for both the maximum 1-hr (125 ppb) and 8-hr (85 ppb) are evaluated. This paper examines one month (1- 30 June, 2004) of the evaluation, using hourly O3 concentration measurements from the EPA's AIRNOW network.
The research presented here was performed under the Memorandum of Understanding between the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) and under agreement number DW13921548. Although it has been reviewed by EPA and NOAA and approved for publication, it does not necessarily reflect their policies or views.
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| PRESENTATION |
(Presented in Alberta, Canada) a Performance Evaluation of the 2004 Release of Models-3 Cmaq |
10/27/2004
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Eder, B. K. AND S. Yu. (Presented in Alberta, Canada) a Performance Evaluation of the 2004 Release of Models-3 Cmaq. Presented at 27th NATO/CCMS International Technical Meeting on Air Pollution Modeling and Its Applications, Alberta, CANADA, October 25 - 29, 2004.
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The Clean Air Act and its Amendments require that the U.S. Environmental Protection Agency (EPA) establish National Ambient Air Quality Standards for O3 and particulate matter and to assess current and future air quality regulations designed to protect human health and welfare. Air quality models, such as EPA's Models-3 Community Multi-scale Air Quality (CMAQ) model, provide one of the most reliable tools for performing such assessments. CMAQ simulates air concentrations and deposition of numerous pollutants on a myriad of spatial and temporal scales to support both regulatory assessment as well as scientific studies conducted by research institutions. In order to characterize its performance and to build confidence in the air quality regulatory community, CMAQ, like any model, needs to be evaluated using observational data. Accordingly, this evaluation compares concentrations of various species (SO4 , NO3 , PM2.5 , NH4 , EC, OC, and O3 (not available at press time), simulated by CMAQ with data collected by the Interagency Monitoring of PROtected Visual Environments (IMPROVE) network, the Clean Air Status and Trends Network (CASTNet) and the Speciated Trends Network (STN).
The research presented here was performed under the Memorandum of Understanding between the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) and under agreement number DW13921548. Although it has been reviewed by EPA and NOAA and approved for publication, it does not necessarily reflect their policies or views.
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| PRESENTATION |
A Performance Evaluation of the 2004 Release of Models-3 Cmaq |
10/27/2004
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Eder, B. K., S. Yu, R. L. Dennis, A. B. Gilliland, S. Howard, AND A. Torian. A Performance Evaluation of the 2004 Release of Models-3 Cmaq. Presented at 27th NATO/CCMS International Technical Meeting of Air Pollution and Its Application, Banff, Canada, October 25-29, 2004.
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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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| PRESENTATION |
Concentrations of Toxic Air Pollutants in the U.S. Simulated By An Air Quality Model |
10/27/2004
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Luecken, D. J. AND W. T. Hutzell. Concentrations of Toxic Air Pollutants in the U.S. Simulated By An Air Quality Model. Presented at 27th NATO/CCMS International Technical Meeting on Air Pollution Modeling and its Application, Banff, Canada, October 25-29, 2004.
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As part of the US National Air Toxics Assessment, we have applied the Community Multiscale Air Quality Model, CMAQ, to study the concentrations of twenty gas-phase, toxic, hazardous air pollutants (HAPs) in the atmosphere over the continental United States. We modified the Carbon Bond 4 chemical mechanism to explicitly account for the additional production and decay of these HAPs, while retaining the full chemistry and radical cycling of the mechanism. Because risk assessments of toxic air pollutants require concentrations over a long period of time, we simulated the full year of 2001 using meteorological data from MM5. We obtained emission inventories of all twenty HAPs from the latest national inventories, and merged them with the inventories of other VOCs and NOx, in order to fully characterize the reactivity of the atmosphere.
Most previous assessments of risks from HAPs have used Gaussian dispersion models to obtain concentrations, so these numerical modeling results are unique because they take into account the full atmospheric chemistry, including the time-varying changes in radical concentrations that affect the ambient concentrations of HAPs. Several HAPs, including formaldehyde and acetaldehyde, can be produced in the atmosphere in greater quantities than they are emitted; so this is the first time that the production of these compounds has been accounted for over a large scale and for a long time period. We present modeled concentrations of formaldehyde, benzene, perchloroethylene, and chloroform, comparison with monitored data, and calculations of risk that result from these concentrations. In addition, we discuss the differences between the results from using a Gaussian dispersion model and CMAQ in the risk assessments of HAPs.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Concentrations of Toxic Air Pollutants in the U.S. Simulated By An Air Quality Model |
10/27/2004
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Luecken, D. J. AND W. T. Hutzell. Concentrations of Toxic Air Pollutants in the U.S. Simulated By An Air Quality Model. Presented at 27th NATO/CCMS International Technical Meeting on Air Pollution Modeling and its Application, Banff, Canada, October 25-29, 2004.
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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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| PRESENTATION |
Source Apportionment of Primary Carbonaceous Aerosol Using the Community Multiscale Air Quality Model |
10/27/2004
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Bhave, P., G. Pouliot, AND M. Zheng. Source Apportionment of Primary Carbonaceous Aerosol Using the Community Multiscale Air Quality Model. Presented at 27th NATO/CCMS International Technical Meeting on Air Pollution Modeling and its Application, Banff, Alberta, Canada, October 25-29, 2004.
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A substantial fraction of fine particulate matter (PM) across the United States is composed of carbon, which may be either emitted in particulate form (i.e., primary) or formed in the atmosphere through gas-to-particle conversion processes (i.e., secondary). Primary carbonaceous aerosol is emitted from numerous sources including motor vehicle exhaust, residential wood combustion, coal combustion, forest fires, agricultural burning, solid waste incineration, food cooking operations, and road dust. Quantifying the primary contributions from each major emission source category is a prerequisite to formulating an effective control strategy for the reduction of carbonaceous aerosol concentrations. A quantitative assessment of secondary carbonaceous aerosol concentrations also is required, but falls outside the scope of the present work.
The research presented here was performed under the Memorandum of Understanding between the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) and under agreement number DW13921548. Although it has been reviewed by EPA and NOAA and approved for publication, it does not necessarily reflect their policies or views.
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| PRESENTATION |
Cfd Simulations Within Complex Urban Building Environments |
08/25/2004
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Huber, A. H., M. Freeman, R. M. Spencer, K. H. Kuehlert, J. Straus, AND B. Bell. Cfd Simulations Within Complex Urban Building Environments. Presented at 5th Symposium on the Urban Environment, Vancouver, BC, Canada, August 23-27, 2004.
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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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| PRESENTATION |
Atmospheric Chemistry and the Relative Importance of Mercury Sources |
08/18/2004
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Bullock, O. R. Atmospheric Chemistry and the Relative Importance of Mercury Sources. Presented at USGS 2004 Mercury Workshop, Reston, VA, August 17-18, 2004.
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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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| PRESENTATION |
Evaluation of An Annual Simulation of Ozone and Fine Particulate Matter Over the Continental United States Which Temporal Features Are Captured? |
10/27/2004
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Hogrefe, C., J. M. Jones, A. B. Gilliland, P. S. Porter, E. L. Gego, R. Gilliam, J. L. Swall, J. S. Irwin, AND S. T. Rao. Evaluation of An Annual Simulation of Ozone and Fine Particulate Matter Over the Continental United States Which Temporal Features Are Captured? Presented at 27th NATO/CCMS International Technical Meeting on Air Pollution and Its Application, Banff, Alberta, Canada, October 25-29, 2004.
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Motivated by growing concerns about the detrimental effects of fine particulate matter (PM2.5) on human health, the U.S. Environmental Protection Agency (EPA) recently promulgated a National Ambient Air Quality Standard (NAAQS) for PM2.5. The PM2.5 standard includes a 24-hour limit (65 ug/m3 for the 98th percentile) and annual (15 ug/m3) limit. Except for a few cases, the annual standard will be the primary concern for attainment issues. Over the next several years, grid-based photochemical models such as the Community Multiscale Air Quality (CMAQ) model (Byun and Ching, 1999) will be used by regulatory agencies to design emission control strategies aimed at meeting and maintaining the NAAQS for O3 and PM2.5. The evaluation of these models for a simulation of current conditions is a necessary prerequisite for using them to simulate future conditions. The evaluation presented in this study focuses on determining the temporal patterns in all components of the modeling system (meteorology, emissions and air quality) and comparing them against available observations. Furthermore, we briefly investigated the weekday/weekend differences in the observed and predicted pollutant concentrations and outlined steps for future research. Since anthropogenic emissions are known to have a distinct weekly cycle, such analyses would help us in evaluating the modeling system's ability to accurately reproduce the observed response to emission changes.
The research presented here was performed under the Memorandum of Understanding between the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) and under agreement number DW13921548. This paper has been reviewed in accordance with the EPA's peer and administrative review policies and approved for presentation and publication.
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| PRESENTATION |
Overview of the Climate Impact on Regional Air Quality (Ciraq) Project |
10/19/2004
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Cooter, E. J., A. B. Gilliland, W. G. Benjey, AND R. Gilliam. Overview of the Climate Impact on Regional Air Quality (Ciraq) Project. Presented at 2004 Models-3 Conference, Chapel Hill, NC, October 18-20, 2004.
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The Climate Impacts on Regional Air Quality (CIRAQ) project will develop model-estimated impacts of global climate changes on ozone and particulate matter (PM) in direct support of the USEPA Global Change Research Program's (GCRP) national air quality assessment. EPA's urban/regional Community Multiscale Air Quality (CMAQ) model will be used to explore the influence of global climate change on U.S. air quality in the mid-term of about 50 years. The planned products for this effort are designed to provide results and analysis for the USEPA GCRP 2007 air quality assessment report. The CIRAQ project is made up of three major components: (1) regional climate scenarios, (2) emissions scenarios, and (3) air quality modeling. Regional climate simulations using MM5 with initial and boundary conditions from the NAS GISS Global Climate Model (GCM) will be performed for reference and future periods under climate change conditions. The RCM results will be processed into "model-ready" meteorology input for the current and future CMAQ simulations. The RCM results will then be analyzed prior to performing the CMAQ simulations. These analyses will be presented in conjunction with the CMAQ results to better understand the air quality predictions in light of meteorological forcing. Current and future emissions scenarios will be based on the most recent 2001 modeling inventory version prepared for the Office of Air Quality Planning and Standards (OAQPS). The inventory will be reprocessed using the RCM simulations for temperature-dependent emissions such as biogenics and mobile emissions. Using the base emissions, multi-year continental domain CMAQ simulations will be performed for the first incremental phase of the project, where climate change forcing is tested without future anthropogenic emissions. Future climate change simulations will be compared against the current CMAQ simulations and results will be provided to the USEPA GCRP national assessment in 2007.
The research presented here was performed under the Memorandum of Understanding between the U.S. Environmental Protection Agency (EPA) and U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) and under agreement number DW13921548. Although it has been reviewed by EPA and NOAA and approved for publication, it does not necessarily reflect their policies or views.
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| PRESENTATION |
Overview of the Climate Impact on Regional Air Quality (Ciraq) Project |
10/19/2004
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Cooter, E. J., A. B. Gilliland, W. G. Benjey, R. Gilliam, AND J. L. Swall. Overview of the Climate Impact on Regional Air Quality (Ciraq) Project. Presented at 2004 Models-3 Conference, Chapel Hill, NC, October 18-20, 2004.
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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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| PRESENTATION |
Overview of the Climate Impact on Regional Air Quality (Cmaq) Project |
10/28/2004
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Cooter, E. J., A. B. Gilliland, W. G. Benjey, R. Gilliam, AND J. L. Swall. Overview of the Climate Impact on Regional Air Quality (Cmaq) Project. Presented at NOAA/EPA Scientist-to-Scientist Meeting Climate Changes and Air Quality Linkages, Boulder, CO, October 27-28, 2004.
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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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| PRESENTATION |
Application of An Air Quality Model (Cmaq) to Predict Concentrations of Toxic Air Pollutants |
09/07/2004
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Luecken, D. J. AND W. T. Hutzell. Application of An Air Quality Model (Cmaq) to Predict Concentrations of Toxic Air Pollutants. Presented at OAQPS Briefing, Research Triangle Park, NC, September 7, 2004.
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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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| PRESENTATION |
Comparison of Spatial Patterns of Pollutant Distribution With Cmaq Predictions |
10/19/2004
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Phillips, S. B. AND P. L. Finkelstein. Comparison of Spatial Patterns of Pollutant Distribution With Cmaq Predictions. Presented at 2004 Models-3 Conference, Chapel Hill, NC, October 18-20, 2004.
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One indication of model performance is the comparison of spatial patterns of pollutants, either as concentration or deposition, predicted by the model with spatial patterns derived from measurements. If the spatial patterns produced by the model are similar to the observations in shape, location, and magnitude it can add to our confidence that the model is performing well. However, deriving spatial patterns from measured pollutant data is not always trivial. Modeling networks are spatially sparse, and frequently biased toward certain types of land use. There is also frequently measurement bias between networks. We will explore the development of reliable spatial models of monitoring data using a variety of simple approaches, and discuss the strengths and weaknesses of some of these. We will then compare the resulting spatial patterns with those predicted by CMAQ, noting similarities and differences. We will consider SO4, NO3, NH4 aerosols, and the wet deposition of SO4, No3, and NH4.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Comparison of Spatial Patterns of Pollutant Distribution With Cmaq Predictions |
10/19/2004
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Phillips, S. B. AND P. L. Finkelstein. Comparison of Spatial Patterns of Pollutant Distribution With Cmaq Predictions. Presented at 2004 Models-3 Conference, Chapel Hill, NC, October 18-20, 2004.
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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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| PRESENTATION |
An Initial Linkage of the Cmaq Modeling System at Neighborhood Scales With a Human Exposure Model |
09/07/2004
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Ching, J. S. AND T. E. Pierce Jr. An Initial Linkage of the Cmaq Modeling System at Neighborhood Scales With a Human Exposure Model. Presented at OAQPS Briefing, US EPA, Research Triangle Park, NC, September 7, 2004.
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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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| PRESENTATION |
High Time-Resolved Comparisons for in-Depth Probing of Cmaq Fine-Particles and Gas Predictions |
10/27/2004
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Dennis, R. L., S. J. Roselle, R. Gilliam, AND J. Arnold. High Time-Resolved Comparisons for in-Depth Probing of Cmaq Fine-Particles and Gas Predictions. Presented at 27th NATO/CCMS International Technical Meeting on Air Pollution Modeling and Its Application, Banff, Alberta, Canada, October 25-29, 2005.
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Model evaluation is important to develop confidence in models and develop an understanding of their predictions. Most comparisons in the U.S. involve time-integrated measurements of 24-hours or longer. Comparisons against continuous or semi-continuous particle and gaseous measurements reveal a wealth of information, providing insights into model functioning not possible with integrated measurements. Several comparisons for the U.S. EPA CMAQ model using U.S. Supersite data from 1999, 2001 and 2002 will be presented. Biases stemming from poor simulation of the pbl (meteorology) will be illustrated and apparent good agreement for conservative species for 24-hour integrated measurement will be shown to be due to offsetting errors. Biases stemming from chemistry will be explored with the help of model sensitivity analyses, particularly related to production of total nitrate. Diagnostic indicators will be used to evaluate ozone production. Biases will be judged for their potential to distort control strategy predictions of the model. Two data collection lessons that will be underlined are: the importance of simultaneous, continuous measurements of species to support interpretive, process-oriented analyses, and the necessity of having a full suite of inorganic gases to develop an understanding of model prediction issues. Most networks lack a full suite of gas and particle measurements.
The research presented here was performed under the Memorandum of Understanding between the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) under agreement number DW13921548. Although it has been reviewed by EPA and NOAA and approved for publication, it does not necessarily reflect their policies or views.
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| PRESENTATION |
High Time-Resolved Comparisons for in-Depth Probing of Cmaq Fine-Particle and Gas Predictions |
10/27/2004
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Dennis, R. L., S. J. Roselle, R. Gilliam, AND J. R. Arnold. High Time-Resolved Comparisons for in-Depth Probing of Cmaq Fine-Particle and Gas Predictions. Presented at 27th NATO/CCMS International Technical Meeting on Air Pollution Modeling and its Application, Banff, Canada, October 25-29, 2004.
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Input errors affect model predictions. The diurnal behavior of two inputs NHx, which partitions in the inorganic system between gas and particle, and EC, a nonreactive emitted specie, is compared for CMAQ predictions and observations. A monthly average diurnal profile based on hourly data is the basic unit for the comparisons with CMAQ predictions, with special investigations of time series to further examine the average behavior. Hourly measurements are available for August 1999 in the Atlanta, GA area and January 2002 for Atlanta, GA, Pittsburgh, PA and St. Louis, MO. For NHx, results for Atlanta and Pittsburgh show that there may be an issue with the diurnal emission profile of NH3 in the summer, particularly in the morning, but not in the winter. For EC, cross-species correlations between EC and other species for a.m. and p.m. rush hours and midday time periods for Atlanta indicate that there may be an issue of missing midday sources of EC in the model emissions inventory. Meteorological issues that affect both species will also be pointed out in the comparisons.
The research presented here was performed under the memorandum of understanding between the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) and under agreement number DW13921548. Although it has been reviewed by EPA and NOAA and approved for publication, it does not necessarily reflect their policies of views.
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| PRESENTATION |
Simulations of Aerosols and Photochemical Species With the Cmaq Plume-in-Grid Modeling System |
10/19/2004
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Godowitch, J. M. Simulations of Aerosols and Photochemical Species With the Cmaq Plume-in-Grid Modeling System. Presented at 2004 Models-3 Conference, Chapel Hill, NC, October 18-20, 2004.
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A plume-in-grid (PinG) method has been an integral component of the CMAQ modeling system and has been designed in order to realistically simulate the relevant processes impacting pollutant concentrations in plumes released from major point sources. In particular, considerable dilution occurs when high NOx or SOx point source emissions are emitted into the rather large volume of Eulerian grid cells specified for typical CMAQ regional modeling domains, which can greatly impact chemical processes and pollutant concentration levels. Consequently, the PinG approach models the dynamic and chemical plume processes on the proper spatial dimensions and temporal scale of the subgrid scale plumes simultaneously during a CMAQ chemical transport model (CTM) simulation.
An overview of the capabilities of the key PinG science algorithms, the Plume Dynamics Model (PDM) processor program and the Lagrangian plume model (PinG module), will be given. These modeling components simulate the relevant physical and chemical processes impacting pollutant species in the subgrid scale plume cells. Until recently, the PinG module performed only gas-phase chemistry, however, the same aerosol algorithms applied in the CMAQ chemical transport model (CTM) have been incorporated into the PinG module to allow aerosol formation processes to also be treated in the pollutant plumes. The effort to adapt and incorporate the aerosol algorithms into PinG will be described. In addition, the sequence of processing steps and decisions to be performed when applying the CMAQ/PinG treatment to a selected set of major point source emissions will be outlined. Finally, results from a model application with the 2004 version of PinG with aerosols will also be shown.
The research presented here was performed under the Memorandum of Understanding between the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) and under agreement number DW13921548. Although it has been reviewed by EPA and NOAA and approved for publication, it does not necessarily reflect their policies or views.
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| PRESENTATION |
Simulations of Aerosols and Photochemical Species With the Cmaq Plume-in-Grid Modeling System |
10/19/2004
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Godowitch, J. M. Simulations of Aerosols and Photochemical Species With the Cmaq Plume-in-Grid Modeling System. Presented at 2004 Models-3 Conference, Chapel Hill, NC, October 18-20, 2004.
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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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| PRESENTATION |
Demonstration of a Coupled Plant-Soil-Deposition Model to Improve Dry Deposition Modeling |
09/30/2004
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Schwede, D. B. Demonstration of a Coupled Plant-Soil-Deposition Model to Improve Dry Deposition Modeling. Presented at Clean Air Markets Division, US EPA, Research Triangle Park, NC, September 30, 2004.
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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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| PRESENTATION |
Air Quality Forecasting With the Community Multiscale Air Quality (Cmaq) Model: A Noaa/EPA Collaboration |
10/06/2004
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Schere, K. L. Air Quality Forecasting With the Community Multiscale Air Quality (Cmaq) Model: A Noaa/EPA Collaboration. Presented at NW-AIRQUEST Sciences Meeting, Pullam, WA, October 6, 2004.
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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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| PRESENTATION |
Premaq: A New Pre-Processor to Cmaq for Air-Quality Forecasting |
10/19/2004
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Otte, T. L., J. A. Pleim, AND G. Pouliot. Premaq: A New Pre-Processor to Cmaq for Air-Quality Forecasting. Presented at 2004 Models-3 Conference, Chapel Hill, NC, October 18-20, 2004.
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A new pre-processor to CMAQ (PREMAQ) has been developed as part of the national air-quality forecasting system. PREMAQ combines the functionality of MCIP and parts of SMOKE in a single real-time processor. PREMAQ was specifically designed to link NCEP's Eta model with CMAQ, and it uses meteorological fields that are specific to the Eta model output suite. We will discuss the technical details of linking the Eta model to CMAQ with PREMAQ in the national air-quality forecasting system.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
What's New in Mcip2? |
10/19/2004
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Otte, T. L. What's New in Mcip2? Presented at 2004 Models-3 Conference, Chapel Hill, NC, October 18-20, 2004.
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An update to CMAQ's Meteorology/Chemistry Interface Processor Version 2 (MCIP2) will be released in August 2004 in conjunction with the next public release of the CMAQ model. MCIP2 is the pre-processor in the CMAQ system that is typically used to perform off-line linkage between meteorological models (e.g., MM5) and CMAQ. Several minor changes to the MCIP2 code will be included in the August 2004 release. Most notable changes include: 1) MCIP2 will process graupel output from advanced microphysics schemes, 2) wind speed and direction at 10 meters will be available in the output, and 3) the header variables for polar stereographic projection have been corrected. All of the changes to MCIP2 will be presented to the user community. Future plans for MCIP2 will also be discussed.
The research presented here was performed under the Memorandum of Understanding between the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) and under agreement number DW13921548. Although it has been reviewed by EPA and NOAA and approved for publication, it does not necessarily reflect their policies or views.
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| PRESENTATION |
A Year-Long Mm5 Evaluation Using a Model Evaluation Toolkit |
10/19/2004
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Gilliam, R., P. Bhave, J. A. Pleim, AND T. L. Otte. A Year-Long Mm5 Evaluation Using a Model Evaluation Toolkit. Presented at 2004 Models-3 Conference, Chapel Hill, NC, October 18-20, 2004.
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Air quality modeling has expanded in both sophistication and application over the past decade. Meteorological and air quality modeling tools are being used for research, forecasting, and regulatory related emission control strategies. Results from air quality simulations have far reaching implications and are closely linked to the meteorological model that drives chemical transport, diffusion, and reactions. Therefore, modeling systems should be evaluated by considering all components involved (Hogrefe et al. 2001). This connection can be achieved by linking the statistical analysis of the air quality model with that of the meteorological model in space and time, in order to distinguish how errors in the air chemistry model are attributed to errors in the meteorological modeling.
An evaluation tool is being developed that will 1) provide a better sense of meteorological model uncertainty; 2) standardize the evaluation process; 3) manage a large volume of evaluation results; 4) make the overall evaluation process more efficient and less labor intensive; and 5) directly link the meteorological model evaluation with the air quality model evaluation.
This study applies the model evaluation tool to a year-long simulation using the Pennsylvania State University (PSU)/National Center for Atmospheric Research (NCAR) fifth-generation mesoscale model (MM5). The results are reported not only to examine the MM5 model performance, but also to demonstrate the effectiveness of the evaluation system. Among the evaluations presented are surface-based 2m temperature, 10m wind, 2m mixing ratio, precipitation and solar radiation. Wind profiler data are also used to examine the ability of MM5 to simulate the vertical distribution of wind over the diurnal cycle. Additionally, a direct linkage between the meteorological and the air quality model performance, specifically ozone and nitrate, is attempted. Only a brief summary of the results are presented here because of manuscript length requirements.
The research presented here was performed under the Memorandum of Understanding between the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) and under agreement number DW 13921548. Although it has been reviewed by EPA and NOAA and approved for publication, it does not necessarily reflect their policies or views.
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| PRESENTATION |
A Year-Long Mm5 Evaluation Using a Model Evaluation Toolkit |
10/19/2004
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Gilliam, R., P. Bhave, AND T. L. Otte. A Year-Long Mm5 Evaluation Using a Model Evaluation Toolkit. Presented at 2004 Models-3 Conference, Chapel Hill, NC, October 18-20, 2004.
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| Abstract:
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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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| PRESENTATION |
Evaluating Temporal and Spatial O3 and PM2.5 Patterns Simulated During An Annual Cmas Application Over the Continental U.S. |
10/19/2004
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Hogrefe, C., J. M. Jones, E. L. Gego, P. S. Porter, J. S. Irwin, A. B. Gilliland, AND S. T. Rao. Evaluating Temporal and Spatial O3 and PM2.5 Patterns Simulated During An Annual Cmas Application Over the Continental U.S. Presented at 2004 Models-3 Conference, Chapel Hill, NC, October 18-20, 2004.
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Over the next several years, grid-based photochemical models such as the Community Multiscale Air Quality (CMAQ) model and REMSAD will be used by regulatory agencies to design emission control strategies aimed at meeting and maintaining the NAAQS for O3 and PM2.5. The evaluation of these models for a simulation of current conditions is a necessary prerequisite for using them to simulate future conditions. In this study, we present evaluation results of an annual simulation for 2001 over the continental U.S. with the CMAQ and REMSAD air quality models driven by meteorological fields generated by MM5 and emissions processed by SMOKE. The evaluation focuses on determining the temporal and spatial patterns in all components of the modeling system (meteorology, emissions and air quality) and comparing them against available observations. In summary, we find that the models exhibit greatest skills at capturing longer-term (seasonal) fluctuations for temperature, wind speed, ozone, sulfate and nitrate. For total PM2.5, ammonium, EC, OC and crustal PM2.5, correlations are highest for the synoptic time scale, implying problems with factors other than meteorology in capturing the baseline (seasonal) fluctuations. For the variables for which hourly measurements were available, correlations were insignificant on the intraday time scale, suggesting that these models in their current setup were not skillful in simulating the shorter-term variations in pollutant levels. We also compared average observed and predicted diurnal cycles for total PM2.5 mass at TEOM monitors. Although the time of occurrence of maxima was simulated well, there is a large difference in the amplitude of the diurnal forcing; both models overestimated observations during nighttime and severely underestimate observations during daytime hours. By comparing the observed and predicted spatial correlation structures for the different temporal components, it was found that the observed intra-day component shows more spatial variability than the predicted one for temperature, wind speed, O3 and PM2.5. The correlation structures for the synoptic and baseline components are generally well-captured by the modeling system for all variables.
In a second thrust of our model evaluation, we briefly investigated the weekday/weekend differences in the observed and predicted pollutant concentrations and outlined steps for future research. Since anthropogenic emissions are known to have a distinct weekly cycle, such analyses would help us in evaluating the modeling system's ability to accurately reproduce the observed response to emission changes. We generated a scatter plot of the average CMAQ predicted difference between weekend daily maximum 1-hr ozone concentrations and weekday daily maximum 1-hr ozone concentrations versus the corresponding difference computed from observations at the same location. This analysis showed that a weekday/weekend cycle of comparable magnitude is indeed present in observed and CMAQ-predicted ozone concentrations during the summer of 2001. However, it is important to ascertain whether the weekday versus weekend differences in ozone concentrations are caused by emission fluctuations or might be largely explained by meteorological effects when analysis is restricted to a single summer season only. Indeed, we show that for the summer of 2001 there was a distinct weekday/weekend fluctuation in temperature at most monitors in the eastern U.S. Most monitors show lower daily maximum temperatures on weekends than on weekdays, and MM5 captures this behavior. Because temperature both directly influences the rate of ozone formation and serves as a proxy for other meteorological parameters conducive to ozone formation, this illustrates that the existence of a weekday/weekend cycle in ozone concentrations for the summer of 2001 can not unequivocally be attributed to cyclical changes in precursor emissions.
The research presented here was performed under the Memorandum of Understanding between the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) and under agreement number DW13921548. Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy
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| PRESENTATION |
Stochastic Description of Subgrid Pollutant Variability in Cmaq |
10/19/2004
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Herwehe, J. A., J. S. Ching, AND J. SWALL. Stochastic Description of Subgrid Pollutant Variability in Cmaq. Presented at 2004 Models-3 Conference, Chapel Hill, NC, October 18 - 20, 2004.
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This paper describes a tool for investigating and describing fine scale spatial variability in model concentration fields with the goal of improving the use of air quality models for driving exposure modeling to assess human risk to hazardous air pollutants or air toxics. Regional scale Eulerian air quality models are typically limited to relatively coarse grid resolutions when simulating mean pollutant concentrations for each grid cell volume, and subgrid pollutant extremes are not represented. Continual improvements in computing power and refinement of nested grid techniques have allowed the regional air quality models to simulate down to grid spacings on the order of one kilometer. Our approach uses exploratory data analysis (EDA) statistical techniques applied to available fine resolution gridded model results to produce stochastic descriptions representing pollutant subgrid variability applicable to the coarser grid resolutions, thereby somewhat bridging the gap between regional scale and neighborhood scale air quality models. Products include, but are not limited to, pollutant probability density functions (pdfs) for use in human exposure models and new parameterizations to represent subgrid pollutant variability in regional air quality prediction systems.
The research presented here was performed under the Memorandum of Understanding between the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) and under agreement number DW13821548. Although is has been reviewed by EPA and NOAA and approved for publication. It does not necessarily reflect their policies or views.,
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| PRESENTATION |
A Bayesian Statistical Approaches for the Evaluation of Cmaq |
10/19/2004
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Swall, J. L. AND J. Davis. A Bayesian Statistical Approaches for the Evaluation of Cmaq. Presented at 2004 Models-3 Conference, Chapel Hill,NC, October 18-20, 2004.
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This research focuses on the application of spatial statistical techniques for the evaluation of the Community Multiscale Air Quality (CMAQ) model. The upcoming release version of the CMAQ model was run for the calendar year 2001 and is in the process of being evaluated by EPA and NOAA scientists and other interested parties. As part of this evaluation, a Bayesian hierarchical approach is taken for evaluating the air concentration of SO4. We evaluate the model against monitoring observations for two different 4-week periods, one in mid-winter and one in mid-summer, for various subregions in the eastern U.S. The observed data come from the U.S. EPA's CASTNet (Clean Air Status and Trends Network) and STN (Speciated Trends Network) monitoring networks.
Exploratory data analysis (EDA) techniques are used to explore the nature of the spatial correlation between observations collected at the various monitoring sites and the model predictions made for the grid cells. Bayesian kriging is then used to interpolate between the given input values in a statistically justifiable manner, taking into account the overall spatial trends in the input values and the potential measurement error. The interpolated field is then compared with other sets of monitoring data and model output fields for evaluation purposes, using the uncertainty measures and distributional information provided by the technique. A number of critical statistical issues are addressed in this work. For instance, we show how to account for the change of support problem, which arises from the fact that the observed data are point measurements, while the model output fields are based on grid cell averages. Bayesian hierarchical models can also be extended to treat related problems in air pollution prediction and model evaluation. For example, statistical methods similar to those used here to address the change of support issue could prove useful in combining several disparate sources of information to provide an improved estimate for a spatially-varying quantity of interest.
The research presented here was performed under the Memorandum of Understanding between the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) and under agreement number DW13921548. Although it has been reviewed by EPA and NOAA and approved for publication, it does not necessarily reflect their policies or views.
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| PRESENTATION |
Cmaq Modeling for Air Toxics at Fine Scales: A Prototype Study |
10/19/2004
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Majeed, M. A., J. S. Ching, T. L. Otte, L. Reynolds, AND R. Tang. Cmaq Modeling for Air Toxics at Fine Scales: A Prototype Study. Presented at 2004 Models-3 Conference, Chapel Hill, NC, October 18 - 20, 2004.
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Toxic air pollutants (TAPs) or hazardous air pollutants (HAPs) exhibit considerable spatial and temporal variability across urban areas. Therefore, the ability of chemical transport models (CTMs), e.g. Community Multi-scale Air Quality (CMAQ), to reproduce the spatial and temporal variability is needed to identify and characterize air toxic hot spots, which are the areas that experience high levels of air toxics. These areas are not only impacted by local sources, but also by the secondary production of many air toxics compounds due to photochemistry. For example, formaldehyde and acetaldehyde have secondary components of oxidant photochemistry. The source distribution, photochemistry, dry and wet depositions of these compounds are scale dependent. Therefore, in order to capture the spatial and temporal variability of these compounds and identify air toxic hot spots, it is necessary to perform air quality simulations at fine scales.
To test the ability of air quality models to simulate air toxic concentration at fine scales, and for its application to assess risk, a prototype study is underway with Delaware as the focus. The CMAQ modeling system is selected because it can perform multi-scale, multi-pollutant simulations for air toxics at a neighborhood scale (~1 km). Its preprocessors, the NCAR-PSU Mesoscale Model Version 5 (MM5) and the SMOKE tool provide the meteorological and emission fields, respectively, at 1 km resolution. The air quality simulations will be performed for 1999 emissions and 2001 meteorology; however, the simulations will be limited to the month of July for this demonstration. Air quality simulations are also performed at 36, 12, and 4 km resolution.
Results of this effort will focus on examining the dependency of grid size in the characterization of these air toxic hot spots and also the impact of regional transport and their secondary production by photochemistry.
The research presented here was performed under the memorandum of understanding between the U. S. Environmental Protection Agency (EPA) and the U. S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) and under agreement number DW13921548. Although it has been reviewed by EPA and NOAA and approved for publication, it does not necessarily reflect their policies or views.
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| PRESENTATION |
Application of Fine Scale Air Toxics Modeling With Cmaq to Hapem5 |
10/19/2004
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Ching, J. S., T. E. Pierce Jr., T. Palma, W. T. Hutzell, R. Tang, A. Cimorelli, AND J. A. Herwehe. Application of Fine Scale Air Toxics Modeling With Cmaq to Hapem5. Presented at 2004 Models-3 Conference, Chapel Hill, NC, October 18 - 20, 2004.
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This paper provides a preliminary demonstration of the EPA neighborhood scale modeling paradigm for air toxics by linking concentration from the Community Multiscale Air Quality (CMAQ) modeling system to the fifth version of the Hazardous Pollutant Exposure Model (HAPEM5). For this demonstration, annual simulations of CMAQ are performed at multiple scales at 36, 12, and 4 km grid sizes. The domain for 36 km size included the continental U. S., while the smaller grid sizes included nested domains that comprised Philadelphia and the state of Delaware. In this application, specific air toxics species were defined and added to the Carbon Bond-IV mechanism. HAPEM5 allowed for the introduction of temporal and spatial (sub-grid) variability. Temporal variability was estimated using hourly outputs for a year at each grid cell. The sub-grid variability was estimated using customized software designed to provide gridded Probability Density Functions (PDFs) to describe the concentration distributions from running the Gaussian dispersion model ISC in fine receptor mode. This application demonstrates that a more robust set of information can be generated for HAPEM5 than by applying to ISC approach. For example, this methodology provides considerably larger dynamic range of temporal and spatial variability not available using ISC alone. Moreover, using CMAQ allows for more accurate estimation of secondary species such as formaldehyde and acetaldehyde, which are not treated explicitly in models such as ISC.
The research presented here was performed under the memorandum of understanding between the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) and under agreement number DW13921548. Although it has been reviewed by EPA and NOAA and approved for publication, it does not necessarily reflect their policies of views.
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| PRESENTATION |
Biogenic Sources for Formaldehyde and Acetaldehyde During Summer Months |
12/15/2004
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Hutzell, W. T. Biogenic Sources for Formaldehyde and Acetaldehyde During Summer Months. Presented at 2004 Fall American Geophysical Union Meeting, San Francisco, CA, December 13-17, 2004.
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Photochemical modeling estimated contributions to ambient concentrations of formaldehyde and acetaldehyde from biogenic emissions over the continental United States during January 2001 (Eos Trans. AGU, 83(47), Fall Meet. Suppl., Abstract A52B-0117). Results showed that maximum contributions occurred over states along the Pacific and southeastern Atlantic coasts. Biogenic contributions were between 10-50% and 20-90% over urban and rural areas, respectively. For formaldehyde, biogenic contributions were equally divided between direct emissions and photochemical production. Photochemistry accounted from 50% to 80% of acetaldehyde concentrations. Both compounds had highest production yields from Nonmethane Volatile Organic Compounds (NVOCs) that contain double bonds between carbon atoms. Ethene emissions were specifically identified to significantly contribute to formaldehyde concentrations. Acetaldehyde production also had large yields from NVOCs containing single bonds between carbon atoms. Isoprene emissions played a minor role compared to other biogenic NVOCs because winter temperatures and solar irradiances reduced its biogenic sources. We have conducted further modeling to assess biogenic contributions during July 2001. Results show that biogenic contributions dominate at most locations in the continental US. In the southern states, maximum contributions move westward to Louisiana and Arkansas but the states along the Pacific coast remain as locations of maximum contributions. Photochemical production controls most concentrations but up to one third of acetaldehyde can be traced to direct emissions. Isoprene emissions generally produced over 50% of formaldehyde concentrations. Acetaldehyde retained the same patterns in production yields from biogenic NVOCs as January 2001. Terrain and its vegetation type affect how these contributions distribute among specific compounds in biogenic emissions.
The research presented here was performed under the memorandum of understanding between the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) and under agreement number DW13921548. Although it has been reviewed by EPA and NOAA and approved for publication, it does not necessarily reflect their policies of views.
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| PRESENTATION |
Simulating Urban Air Toxics Over Continental and Urban Scales |
10/19/2004
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Hutzell, W. T., D. J. Luecken, AND J. S. Ching. Simulating Urban Air Toxics Over Continental and Urban Scales. Presented at 2004 Models-3 Conference, Chapel Hill, NC, October 18 - 20, 2004.
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The US EPA is evaluating a version of the CMAQ model to support risk assessment for the exposure to Hazardous Air Pollutants (HAPs). The model uses a variant of the CB4 chemical mechanism to simulate ambient concentrations of twenty HAPs that exist primarily as gaseous compounds such as formaldehyde, acetaldehyde, 1,3-butadiene and benzene. Our evaluation uses results from annual simulations at two horizontal resolutions, 36X36 km2 and 4X4 km2, for the year 2001. The former resolution has a domain that covers the Continental United States. The latter resolution's domain nests inside the continental domain and focuses on the Philadelphia metropolitan area. The comparison examines observations versus a subset of predicted HAPs that include formaldehyde, acetaldehyde, benzene, perchloroethylene, and chloroform. Both simulations show an agreement with observations generally within a factor of two. The 4X4 km2 simulation appears to not have a better agreement in terms of root mean error and correlation coefficient by can have a lower bias and better match how observations vary over time. For both resolutions, the comparisons between time series show that agreement to observations depends on season and location. We propose that these behaviors result from the boundary conditions, emission inventory and the chemistry of a HAP. Differences between the simulations indicate that spatially resolving emissions, transport, and chemistry also explains differences from observations because the smaller resolution better captures the temporal variability of observed concentrations.
The research presented here was performed under the Memorandum of Understanding between the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) and under agreement number DW13921548. Although it has been reviewed by EPA and NOAA and approved for publication, it does not necessarily reflect their policies or views.
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| PRESENTATION |
Simulating Urban Air Toxics Over Continental and Urban Scales |
10/19/2004
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Hutzell, W. T., D. J. Luecken, AND J. S. Ching. Simulating Urban Air Toxics Over Continental and Urban Scales. Presented at 2004 Models-3 Conference, Chapel Hill, NC, October 18-20, 2004.
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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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| PRESENTATION |
A Chemical Sensitivity Analysis With Cmaq: Diagnostic Testing in Base Case and Control Strategies in the Southeast U.S. |
10/19/2004
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Arnold, J. R. AND R. L. Dennis. A Chemical Sensitivity Analysis With Cmaq: Diagnostic Testing in Base Case and Control Strategies in the Southeast U.S. Presented at 2004 Models-3 Conference, Chapel Hill, NC, October 18-20, 2004.
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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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| PRESENTATION |
New Developments in the Community Multiscale Air Quality (Cmaq) Model |
10/19/2004
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Pleim, J. A., S. J. Roselle, J. O. Young, G. L. Gipson, AND R. Mathur. New Developments in the Community Multiscale Air Quality (Cmaq) Model. Presented at 2004 Models-3 Conference, Chapel Hill, NC, October 18 - 20, 2004.
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CMAQ model research and development is currently following two tracks at the Atmospheric Modeling Division of the USEPA. Public releases of the community model system for research and policy analysis is continuing on an annual interval with the latest release scheduled for August of 2004. The publicly released system includes the latest advancements in scientific modeling research and improvements for model efficiency. The other CMAQ track is for the National Air Quality Forecast system, which is a joint NOAA/USEPA project to provide nationwide operational model forecasts of ozone and aerosols. The AQF system includes an optimized version of CMAQ coupled to NCEP's North American Mesoscale forecast model, which is currently the Eta model. The version CMAQ used in the AQF system has been specifically tailored to the forecast application and NCEP's operational computing environment. The two tracks have been quite synergistic for development and evaluation. This presentation will provide an overview of the latest developments in both the community system and the AQF system. Ongoing and future work will also be outlined.
The research presented here was performed under the Memorandum of Understanding between the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) and under agreement number DW13921548. Although it has been reviewed by EPA and NOAA and approved for publication, it does not necessarily reflect their policies or views.
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| PRESENTATION |
Computational Aspects of the Air Quality Forecasting Version of Cmaq (Cmaq-F) |
10/19/2004
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Wong, D. C. AND J. O. Young. Computational Aspects of the Air Quality Forecasting Version of Cmaq (Cmaq-F). Presented at 2004 Models-3 Conference, Chapel Hill, NC, October 18 - 20, 2004.
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The air quality forecast version of the Community Modeling Air Quality (CMAQ) model (CMAQ-F) was developed from the public release version of CMAQ (available from http://www.cmascenter.org), and is running operationally at the National Weather Service's National Centers for Environmental Prediction (NCEP). Most of the modifications to CMAQ focus on tailoring the model's performance to the operational hardware and the parallel computing environment at NCEP and effectively managing the parallel input and output (I/O) processes to achieve scalability. This has been accomplished by asynchronously overlapping computation with I/O writing to disk (WTD) by a dedicated processor.
In this paper, we describe two different ways of placing the WTD processor. Benchmark results with regards to the WTD processor placement and an extension to more than one WTD processor are presented. In addition, a benchmark comparison between the I/O implementation in the CMAQ-F and the community version of CMAQ is provided.
The research presented here was performed under the Memorandum of Understanding between the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) and under agreement number DW13921548. Although it has been reviewed by EPA and NOAA and approved for publication, it does not necessarily reflect their policies or views.
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| PRESENTATION |
Diagnostic Evaluation of Cmaq Response of Inorganic Fine Particulate Species of Emissions Changes |
10/19/2004
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Dennis, R. L., S. J. Roselle, C. Nolte, AND P. Bhave. Diagnostic Evaluation of Cmaq Response of Inorganic Fine Particulate Species of Emissions Changes. Presented at 2004 Models-3 Conference, ChapelHill, NC, October 18-20, 2004.
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The Gas Ratio proposed by Spyros Pandis, which identifies whether the system is nitric acid or ammonia limited, is an indicator of the sensitivity of the inorganic system to changes in conditions. This indicator is investigated in this work to find out how well it can diagnose sensitivity of the model with respect to changes in inorganic emissions. First, a sense of CMAQ's performance on the Gas Ratio indicator is presented, showing the range over which reasonable performance is obtained, and showing how bias in the individual species of the indicator can affect the indicator. Then a model study of the sensitivity of the Gas Ratio to changes in inorganic emissions and how this translates to the degree of nitrate replacement for reductions in sulfate is presented. An examination of how potential errors in the ammonia emissions inventory in the desert West and the very upper Mid-west could be affecting the predicted response of CMAQ to emissions changes will complete the talk.
The research presented here was performed under the Memorandum of Understanding between the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) under agreement number DW13921548. Although it has been reviewed by EPA and NOAA and approved for publication, it does not necessarily reflect their policies or views.
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| PRESENTATION |
Using Cmaq-Aim to Evaluate the Gas-Particle Partitioning Treatment in Cmaq |
10/19/2004
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Nolte, C., P. Bhave, R. L. Dennis, K. M. Zhang, AND A. S. Wexler. Using Cmaq-Aim to Evaluate the Gas-Particle Partitioning Treatment in Cmaq. Presented at 2004 Models-3 Conference, Chapel Hill, NC, October 18 - 20, 2004.
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The Community Multi-scale Air Quality model (CMAQ) aerosol component utilizes a modal representation, where the size distribution is represented as a sum of three lognormal modes. Though the aerosol treatment in CMAQ is quite advanced compared to other operational air quality models, various members of the CMAQ community have commented that improvements to the aerosol module should be made in order to bring it to the state of the science found in research-grade air quality models. Among the shortcomings noted are that (1) a trimodal representation is insufficient to resolve the aerosol size and composition distribution; (2) interactions of the gas phase with coarse particles, such as sea-salt, are neglected; and (3) the assumption of instantaneous equilibrium between gas-phase species and fine-mode aerosol is inaccurate. In the present study, we seek to understand the effects of the latter two assumptions on predicted fine-particle mass and chemical composition in regional-scale air quality models.
A sectional aerosol module that uses dynamic mass transfer rather than assuming instantaneous equilibrium between the gas and particle phases has been developed and integrated into the Community Multi-scale Air Quality model (CMAQ) (Zhang and Wexler, 2004). The resulting model, CMAQ-AIM, provides a useful platform to gauge the impact of certain assumptions made in the CMAQ aerosol module.
The research presented here was performed under the Memorandum of Understanding between the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) and under agreement number DW13921548. Although it has been reviewed by EPA and NOAA and approved for publication, it does not necessarily reflect their policies or views.
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| PRESENTATION |
An Annual Evaluation of the 2004 Release of Models-3 Cmaq |
10/19/2004
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Eder, B. K., S. Yu, R. L. Dennis, A. B. Gilliland, S. Howard, AND A. Torian. An Annual Evaluation of the 2004 Release of Models-3 Cmaq. Presented at 2004 Models-3 Conference, Chapel Hill, NC, October 18-20, 2004.
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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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| PRESENTATION |
Operational and Diagnostic Evaluation of the Ozone Forecasts By the Eta-Cmaq Model Suite During the 2002 New England Air Quality Study (Neaqs) |
10/19/2004
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Yu, S., R. Mathur, D. Kang, K. L. Schere, B. K. Eder, AND J. A. Pleim. Operational and Diagnostic Evaluation of the Ozone Forecasts By the Eta-Cmaq Model Suite During the 2002 New England Air Quality Study (Neaqs). Presented at 2004 Models-3 Conference, Chapel Hill, NC, October 18 - 20, 2004.
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Ozone (O3), a secondary pollutant, is created in part by emissions from anthropogenic and biogenic sources. It is necessary for local air quality agencies to accurately forecast ozone concentrations to warn the public of unhealthy air and to encourage people to voluntarily reduce emissions producing activities.
The research presented here was performed under the Memorandum of Understanding between the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) and under agreement number DW13921548. Although it has been reviewed by EPA and NOAA and approved for publication, it does not necessarily reflect their policies or views.
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| PRESENTATION |
Temporal Signatures of Air Quality Observations and Model Outputs: Do Time Series Decomposition Methods Capture Relevant Time Scales? |
10/27/2004
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Porter, P. S., J. L. Swall, R. Gilliam, E. L. Gego, C. Hogrefe, J. S. Irwin, AND S. T. Rao. Temporal Signatures of Air Quality Observations and Model Outputs: Do Time Series Decomposition Methods Capture Relevant Time Scales? Presented at 27th NATO/CCMS International Technical Meeting on Air Pollution Modeling and its Application, Banff, BC, CANADA, October 25 - 29, 2004.
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Time series decomposition methods were applied to meteorological and air quality data and their numerical model estimates. Decomposition techniques express a time series as the sum of a small number of independent modes which hypothetically represent identifiable forcings, thereby helping to untangle complex processes. Mode-to-mode comparison of observed and modeled data provides a mechanism for model evaluation.
The decomposition methods included empirical orthogonal functions (EOF), empirical mode decomposition (EMD), and wavelet filters (WF). EOF, a linear method designed for stationary time series, is principal component analysis (PCA) applied to time-lagged copies of a given time series. EMD is a relatively new nonlinear method that operates locally in time and is suitable for nonstationary and nonlinear processes; it is not, in theory, bandwidth limited, and the number of modes is automatically determined. Wavelet filters are linear and band-width guided with the number of modes set by the analyst.
The purpose of this paper is to compare the performance of decomposition techniques in characterizing time scales in meteorological and air quality variables. Aiding this comparison is an analysis of simulated time series that have features in common with observations. These features include a smooth wave with a period that slowly changes from 40 to 60 days, a cosine wave with a period of one week, and additive red noise. Use of a 40 to 60 day simulated wave was motivated by the Julian-Madden effect observed in some chosen because they represent relatively easy and difficult tests, respectively, for decomposition methods. Modeled estimates of temperature are forced to closely track observations from a dense observation network; temporal modes of observations and model temperature time series, while the existence of a one-week wave has been the object of many air quality studies as it is considered an indication of anthropogenic forcing, estimates should therefore be in close agreement. Comparison of modeled and observed PM2.5, on the other hand, is a more difficult test for decomposition techniques.
The research presented here was performed under the Memorandum of Understanding between the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) and under agreement number DW13921548. Although this manuscript has been peer reviewed by EPA and NOAA and approved for publication, it does not necessarily represent their views or policies.
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| PRESENTATION |
Cmaq Modeling Program at the U.S. EPA |
10/15/2004
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Rao, S. T. AND K. L. Schere. Cmaq Modeling Program at the U.S. EPA. Presented at Border Air Quality Symposium, Waterloo, Canada, October 15, 2004.
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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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| PRESENTATION |
October 18th 20th, 2004 Cmas Workshop |
10/19/2004
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Rao, S. T. AND W. Jiang. October 18th 20th, 2004 Cmas Workshop. Presented at 2004 Models-3 Conference, Chapel Hill, NC, October 18 - 20, 2004.
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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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| PRESENTATION |
Adaptation and Application of the Community Multiscale Air Quality (Cmaq) Modeling System for Real-Time Air Quality Forecasting During the Summer of 2004 |
10/20/2004
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Mathur, R., J. A. Pleim, T. L. Otte, K. L. Schere, G. Pouliot, J. O. Young, B. K. Eder, D. Kang, S. Yu, H. Lin, J. McQueen, P. Lee, M. Tsidulko, AND D. C. Wong. Adaptation and Application of the Community Multiscale Air Quality (Cmaq) Modeling System for Real-Time Air Quality Forecasting During the Summer of 2004. Presented at 2004 Models-3 Conference, Chapel Hill, NC, October 18 - 20, 2004.
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The ability to forecast local and regional air pollution events is challenging since the processes governing the production and sustenance of atmospheric pollutants are complex and often non-linear. Comprehensive atmospheric models, by representing in as much detail as possible the various dynamical, physical, and chemical processes regulating the atmospheric fate of pollutants, provide a scientifically sound tool for air quality forecasting. The availability of increased computational power coupled with advances in the computational structure of the models has now enabled their use in real-time air quality forecasting. In recent years, such efforts have been used to provide daily guidance to state and local air quality forecasters (e.g., McHenry et al., 2004) as well as to aid in design of field experiments (e.g., Flatoy et al., 2000; Uno et al., 2003; Lawrence et al., 2003). Recently, the National Oceanic and Atmospheric Administration (NOAA), and the U.S. Environmental Protection Agency (EPA) partnered to develop a real-time air-quality forecasting (AQF) system that is based on the National Weather Service (NWS) National Centers for Environmental Prediction's (NCEP's) Eta model (Black, 1994) and the U.S. EPA's Community Multiscale Air Quality (CMAQ) Modeling System (Byun and Ching, 1999). An initial version of the system was deployed to forecast surface-level O3 pollution over the northeast U.S. during the summer of 2003 (Davidson et al., 2003). In this paper we summarize further enhancements to the AQF modeling system as well as initial results from its forecast applications during the summer of 2004.
The research presented here was performed under the Memorandum of Understanding between the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) and under agreement number DW13921548. Although it has been reviewed by EPA and NOAA and approved for publication, it does not necessarily reflect their policies or views
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| PRESENTATION |
Seasonal Nh 3 Emissions for Annual 2001 Cmaq Simulation: Inverse Model Estimation and Evaluation |
10/19/2004
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Gilliland, A. B., S. J. Roselle, R. Pender, AND R. L. Dennis. Seasonal Nh 3 Emissions for Annual 2001 Cmaq Simulation: Inverse Model Estimation and Evaluation. Presented at 2004 Models-3 Conference, Chapel Hill, NC, October 18-20, 2004.
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The formation of ammonium nitrate aerosols is often limited by ammonia (NH3), and sulfate aerosols are predominantly in the form of ammonium sulfate. While NH3plays a central role in the prediction of nitrate and sulfate aerosols, inherent uncertainty exists in NH3 emissions because of the predominant sources, animal husbandry and fertilizer application. The temporal variability in fertilizer application and the meteorological dependence of NH3 volatilization from animal waste suggest that a strong seasonal variability should be expected in the emissions. Current work by Pinder et al. [2004] provides the first farm-level model for NH3 emissions from dairy cattle, and Goebes et al. [2003] provides a seasonally varying fertilizer inventory for NH3. Top-down estimates of NH3 seasonally varying emissions for all combined source types have been developed by Gilliland et al. [2003] using an inverse modeling method. Currently, these studies provide the most comprehensive information available for seasonally distributing NH3 emissions for air quality modeling. Combining this information, we have constructed a best prior estimate of seasonal scaling factors for NH3 emissions. These emissions were then used in an annual 2001 simulation using the USEPA Community Multiscale Air Quality (CMAQ) model for a contiguous United States domain. The objective of this study is to evaluate the reasonableness of these prior NH3 emission scaling factors and then test the inverse modeling method used to produce revised top-down seasonal scaling factors for the modeling domain. First, we will describe the approach used to generate our best prior estimate of NH3 seasonal scaling factors. Evaluation results against the National Atmospheric Deposition Program (NADP) precipitation chemistry network and several speciated aerosol networks will then be presented with a primary focus on monthly and seasonal time scales. Posterior inverse modeling emission estimates will be presented to conclude the analyses.
The research presented here was performed under the Memorandum of Understanding between the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) and under agreement number DW13921548. Although it has been reviewed by EPA and NOAA and approved for publication, it does not necessarily reflect their policies or views.
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| PRESENTATION |
Seasonal and Regional Variations of Primary and Secondary Organic Aerosols Over the Continental United States: Observation-Based Estimates and Model Evaluation |
10/19/2004
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Yu, S., R. L. Dennis, P. Bhave, AND R. Mathur. Seasonal and Regional Variations of Primary and Secondary Organic Aerosols Over the Continental United States: Observation-Based Estimates and Model Evaluation. Presented at 2004 Models-3 Conference, Chapel Hill, NC, October 18-20, 2004.
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Due to the lack of an analytical technique for directly quantifying the atmospheric concentrations of primary (OCpri) and secondary (OCsec) organic carbon aerosols, different indirect methods have been developed to estimate their concentrations. In this study, seasonal and regional variations of OCpri and OCsec over the continental U.S. for the year 2001 were estimated by using observed OC and elemental carbon (EC) data from Interagency Monitoring of Protected Visual Environments (IMPROVE) and Southeastern Aerosol Research and Characterization (SEARCH) networks, coupled with the primary OC/EC ratios, (OC/EC)pri, obtained from an emission/transport-model (US EPA Models-3/Community Multiscale Air Quality (CMAQ) model) (i.e., emission/transport of primary OC/EC ratio method). These observation-based estimates show that the yearly mean OCpri concentrations vary greatly by location from 0.27 µg C m-3 to 3.72 µg C m-3 (0.71 +/- 0.82 µg C m-3, mean +/- standard deviation), while the yearly mean OCsec concentrations vary from 0.16 µg C m-3 to 1.76 µg C m-3 (0.61 +/- 1.04 µg C m-3). Seasonal analysis shows that OCsec concentrations are 0.34 +/- 0.62, 0.47 +/- 0.86, 0.80 +/- 1.03, and 0.72 +/- 1.30 µg C m-3 in winter, spring, summer, and fall, respectively, making 30, 41, 51, and 42% contributions to OC respectively. Regional analysis indicates that both OCpri and OCsec concentrations are the highest over the southeast area (yearly mean OCpri: 1.00 +/- 1.23 µg C m-3 and OCsec: 1.25 +/- 0.96 µg C m-3) in all seasons. It is found that OCpri accounts for a large fraction of OC over the Northeast, Southeast, Midwest, West and Midwest (>56%) in all seasons except summer, during which OCpri and OCsec concentrations make approximately equal contributions to OC. On the basis of comparison of OCpri and OCsec at the nearest paired urban/rural sites from SEARCH, the yearly mean OCpri concentrations at the urban sites contribute 71 to 80% to OC, larger than the OCpri contributions at the corresponding paired rural sites (54 to 74%). In contrast, the yearly mean OCsec concentrations at rural sites frequently exceed those at the nearby urban sites. The higher OCsec concentrations during the summer at the three rural sites result in the higher yearly contributions of OCsec to OC (41 to 46%) than at the corresponding paired urban sites (20 to 29%).
The comparisons of the model and observation-based estimates show that over the continental United States, the modeled OCsec concentrations are 0.49 +/- 0.45, 0.67 +/- 0.59, 0.96 +/- 0.99, 1.06 +/- 1.03, and 0.84 +/- 0.87 µg C m-3 in winter, spring, summer, fall and year, respectively, slightly higher than the observation-based concentration estimates listed above. The modeled OCpri concentrations are 0.74 +/- 0.96, 0.58 +/- 0.81, 0.86 +/- 1.02, 0.69 +/- 0.63, and 0.72 +/- 0.86 µg C m-3 in winter, spring, summer, fall and year, respectively, very close to those of the observations which are 0.70 +/- 0.82, 0.60 +/- 0.58, 0.73 +/- 1.00, 0.78 +/- 0.80, and 0.71 +/- 0.82 µg C m-3.
The research presented here was performed under the Memorandum of Understanding between the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) and under agreement number DW13921548. Although it has been reviewed by EPA and NOAA and approved for publication, it does not necessarily reflect their policies or views.
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| PRESENTATION |
A Performance Evaluation of the Eta 3 Cmaq Air Quality Forecast Model |
10/20/2004
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Eder, B. K., T. L. Otte, J. A. Pleim, G. Pouliot, K. L. Schere, J. O. Young, D. Kang, H. Lin, AND S. Yu. A Performance Evaluation of the Eta 3 Cmaq Air Quality Forecast Model. Presented at 2004 Models-3 Conference, Chapel Hill, NC, October 18-20, 2004.
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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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| PRESENTATION |
A Performance Evaluation of the Eta Cmaq Quality Forecast Model |
10/17/2004
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Kang, D., B. K. Eder, R. Mathur, S. Yu, AND K. L. Schere. A Performance Evaluation of the Eta Cmaq Quality Forecast Model. Presented at 27th NATO/CCMS International Technical Meeting on Air Pollution and Its Application, Banff, Canada, October 25-29, 2004.
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| Abstract:
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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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| PRESENTATION |
Linking Eta Model With the Community Multiscale Air Quality (Cmaq) Modeling System: Ozone Boundary Conditions |
10/27/2004
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Lee, P., J. A. Pleim, R. Mathur, J. McQueen, M. Tsidulko, G. DiMego, M. Iredell, T. L. Otte, G. Pouliot, J. O. Young, D. C. Wong, D. Kang, M. Hart, AND K. L. Schere. Linking Eta Model With the Community Multiscale Air Quality (Cmaq) Modeling System: Ozone Boundary Conditions. Presented at 27th NATO/CCMS International Technical Meeting on Air Pollution Modeling and its Application, Banff, AB, CANADA, October 25 - 29, 2004.
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A prototype surface ozone concentration forecasting model system for the Eastern U.S. has been developed. The model system is consisting of a regional meteorological and a regional air quality model. It demonstrated a strong prediction dependence on its ozone boundary conditions. This study investigated the sensitivity of several schemes in providing the boundary condition. The schemes range from climatologic data to real time global general circulation model derived ozone concentrations. Result confirmed the strong dependence between the forecasted surface ozone concentration and the upwind ozone boundary condition. Furthermore, it indicated that refined coupling treatment between the three models is required to make proper derivation and usage of the global model based ozone concentration boundary condition.
The research presented here was performed under the Memorandum of Understanding between the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) and under agreement number DW13921548. Although it has been reviewed by EPA and NOAA and approved for publication, it does not necessarily reflect their policies or views.
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| PRESENTATION |
Testing Physics and Chemistry Sensitivities in the U.S. EPA Community Multiscale Air Quality Modeling System (Cmaq) |
10/27/2004
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Arnold, J. R. AND R. L. Dennis. Testing Physics and Chemistry Sensitivities in the U.S. EPA Community Multiscale Air Quality Modeling System (Cmaq). Presented at 27th NATO/CCMS International Technical Meeting on Air Pollution Modeling and its Application, Banff, AB, CANADA, October 25 - 29, 2004.
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Uncertainties in key elements of emissions and meteorology inputs to air quality models (AQMs) can range from 50 to 100% with some areas of emissions uncertainty even higher (Russell and Dennis, 2000). Uncertainties in the chemical mechanisms are thought to be smaller (Russell and Dennis, 2000) but can range to 30% or more as new techniques are applied to re-measure reaction rate constants and yields. Single perturbation sensitivity analyses have traditionally been used with AQMs to characterize effects of these uncertainties on peak predicted ozone concentration ([O3]).
However, confidence in AQM applications depends on understanding the physical and chemical model dynamics in full emissions cases and in cases with proposed controls on oxides of nitrogen (NO+NO2=NOx) and/or volatile organic compounds (VOC). With a sensitivity analysis, emissions control runs depict the true photochemical system change which we define as the O3 control response, deltaO3/deltaENOx and deltaO3/deltaEVOC, where deltaENOx or deltaEVOC is the type and amount of control required to reduce O3 to acceptable levels. The model's most important sensitivity, correspondingly, is how its control response is changed by uncertain inputs and parameters, not simply how the resultant [O3] might be changed by the uncertainties in a full emissions case. We define that latter quantity as DeltaO3, or the change in [O3] due only to the uncertainty perturbation with full emissions.
This work was performed under a Memorandum of Understanding between the U.S. Environmental Protection Agency (EPA) and the National Oceanic and Atmospheric Administration (NOAA) of the U.S. Department of Commerce and under agreement number DW13921548. Although it has been reviewed by EPA and NOAA and approved for publication, it does not necessarily reflect policies or views of either agency.
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| PRESENTATION |
Paradigm Using Joint Deterministic Grid Modeling and Sub-Grid Variability Stochastic Description as a Template for Model Evaluation |
10/19/2004
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Ching, J. S., J. A. Herwehe, AND J. L. Swall. Paradigm Using Joint Deterministic Grid Modeling and Sub-Grid Variability Stochastic Description as a Template for Model Evaluation. Presented at 2004 Models-3 Conference, Chapel Hill, NC, October 18-20, 2004.
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The goal of achieving verisimilitude of air quality simulations to observations is problematic. Chemical transport models such as the Community Multi-Scale Air Quality (CMAQ) modeling system produce volume averages of pollutant concentration fields. When grid sizes are such that significant within-grid variability is not resolved, the comparison against one or more point measurements is not, in general, expected to be equal, except under very special limited circumstances. Yet, since models are judged by such comparative analyses, there is an implicit assumption (and a hope) that the point measurement is representative of the grid model prediction, and vice versa.
In this paper, we accept that there will always be a component of within-grid concentration variability to grid models, even at fine scale grid resolution. Such variability arises from the distribution of emission sources within individual gird cells. Additionally, there may be significant variability arising from coupled chemical and turbulent interactions. On the other hand, general guidance for locating monitors may not necessarily mean that such measurements will be representative of the grid model fields. This desired goal is only possible for idealized horizontally homogeneous fully dispersed, uniform source distributions situation. In fact, especially in urban areas even with an ideally placed monitor, it is a rare case in which the monitors and grid model output are really expected to be completely comparable.
In the presence of inherent within-grid variability, we suggest that it is more reasonable to reformulate the comparative basis between models and monitoring information by recognizing and accepting the a priori presence of within-grid variability
Examples using CMAQ at neighborhood scales and the corresponding model outputs that represent sub-grid variability, along with observations, are presented to illustrate this paradigm.
The research presented here was performed under the memorandum of understanding between the U. S. Environmental Protection Agency (EPA) and the U. S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) and under agreement number DW13921548. Although it has been reviewed by EPA and NOAA and approved for publication, it does not necessarily reflect their policies or views.
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| PRESENTATION |
Objective Reduction of the Space-Time Domain Dimensionality for Evaluating Model Performance |
10/27/2004
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Gego, E. L., P. S. Porter, C. Hogrefe, A. B. Gilliland, J. L. Swall, J. S. Irwin, AND S. T. Rao. Objective Reduction of the Space-Time Domain Dimensionality for Evaluating Model Performance. Presented at 27th NATO/CCMS International Technical Meeting on Air Pollution Modeling and its Application, Banff, Canada, October 25-29, 2004.
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In the United States, photochemical air quality models are the principal tools used by governmental agencies to develop emission reduction strategies aimed at achieving National Ambient Air Quality Standards (NAAQS). Before they can be applied with confidence in a regulatory setting, models' ability to simulate key features embedded in the air quality observations at an acceptable level must be assessed. With this concern in mind, the U.S. Environmental Protection Agency (EPA) has recently completed several executions of the Community Multiscale Air Quality model (CMAQ) and the Regional Modeling System for Aerosols and Deposition model (REMSAD) to simulate air quality over the contiguous United States during year 2001 with a horizontal cell size of 36 km x 36 km. The meteorological model MM5 and the emission processor SMOKE were used to generate the input fields necessary for CMAQ and REMSAD. See Hogrefe et al (2004a) and Eder and Yu (2004) for more information about model settings.
The research presented here was performed under the Memorandum of Understanding between the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) and under agreement number DW13921548. This paper has been reviewed in accordance with the EPA's peer and administrative review policies and approved for presentation and publication.
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| PRESENTATION |
Using the Air Quality Model to Analyze the Concentrations of Air Toxics Over the Continental U.S. |
12/01/2004
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Luecken, D. J. AND W. T. Hutzell. Using the Air Quality Model to Analyze the Concentrations of Air Toxics Over the Continental U.S. Presented at CRC Mobile Source Air Toxics Workshop, Scottsdale, AZ, November 30-December 2, 2004.
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The U.S. Environmental Protection Agency is examining the concentrations and deposition of hazardous air pollutants (HAPs), which include a large number of chemicals, ranging from non reactive (i.e. carbon tetrachloride) to reactive (i.e. formaldehyde), exist in gas, aqueous, and/or particle phases and are emitted from a variety of sources. Several HAPs, such as formaldehyde, acetaldehyde and acrolein, can be produced in the atmosphere in significant quantities, so it is important to adequately characterize this complex chemistry. To do this, we have modified a 3 D photochemical air quality model, the Community Multiscale Air Quality (CMAQ) modeling system, to simulate the concentration of toxic air pollutants over large spatial and temporal scales. The model has been applied to study 20, high priority HAPs that exist in the gas phase, including such compounds as benzene, formaldehyde, acrolein, acetaldehyde, and chloroform. We describe the development of chemical mechanisms appropriate for HAPs; the incorporation of the chemistry and physics of HAPs into a chemical transport model; and the simulation over an entire year and the continental U.S. The analysis of the model results presented here focuses on formaldehyde and acrolein. There is substantial temporal and spatial variability in HAP concentrations. The fraction of secondarily-produced formaldehyde and acrolein can be large, with the contribution of atmospheric chemistry varying in importance across the country and across seasons. The contribution of mobile sources to ambient concentrations depends on both the primary emissions from mobile sources as well as the amount that is formed in the atmosphere from mobile source emissions of other VOCs.
The research presented here was performed under the Memorandum of Understanding between the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) and under agreement number DW13921548. Although it has been reviewed by EPA and NOAA and approved for publication, it does not necessarily reflect their policies or views.
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| PRESENTATION |
Regional Air Quality Modeling Issues Related to Animal Feeding Operations (Afos) |
12/07/2004
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PIERCE, T. E., R. L. DENNIS, A. GILLILAND, D. B. SCHWEDE, AND J. T. WALKER. Regional Air Quality Modeling Issues Related to Animal Feeding Operations (Afos). Presented at Regional Science Workshop on Animal Feeding Operations (AFOS), Adelphi, MD, December 06 - 09, 2004.
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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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| PRESENTATION |
Community Multiscale Air Quality (Cmaq) Model Developments |
12/08/2004
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SCHERE, K. L., J. PLEIM, P. BHAVE, AND B. K. EDER. Community Multiscale Air Quality (Cmaq) Model Developments. Presented at 29th Annual EPA-A&WMA Information Exchange , Research Triangle Park, NC, December 07 - 08, 2004.
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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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| PRESENTATION |
Biogenic Sources of Formaldehyde and Acetaldehyde During Summer and Winter Conditions |
12/16/2004
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HUTZELL, W. T. Biogenic Sources of Formaldehyde and Acetaldehyde During Summer and Winter Conditions. Presented at American Geophysical Union's Fall Meeting, San Francisco, CA, December 13 - 17, 2004.
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Photochemical modeling estimated contributions to ambient concentrations of formaldehyde and acetaldehyde from biogenic emissions over the continental United States during January 2001 (Eos Trans. AGU, 83(47), Fall Meet. Suppl., Abstract A52B-0117). Results showed that maximum contributions occurred over states along the Pacific and southeastern Atlantic coasts. Biogenic contributions were between 10-50 percent and 20-90 percent over urban and rural areas, respectively. For formaldehyde, biogenic contributions were equally divided between direct emissions and photochemical production. Photochemistry accounted from 50 to 80 percent of acetaldehyde concentrations. Both compounds had highest production yields from Nonmethane Volatile Organic Compounds (NVOCs) that contain double bonds between carbon atoms. Ethene emissions were specifically identified to significantly contribute to formaldehyde concentrations. Acetaldehyde production also had large yields from NVOCs containing single bonds between carbon atoms. Isoprene emissions played a minor role compared to other biogenic NVOCs because winter temperatures and solar irradiances reduced its biogenic sources. We have conducted further modeling to assess biogenic contributions during July 2001. Results show that biogenic contributions dominated at most locations in the continental US. In the southern states, maximum contributions moved westward to Louisiana and Arkansas but the states along the Pacific coast remained as locations of maximum contributions. Photochemical production controled most concentrations but up to one third of acetaldehyde can be traced to direct emissions. Isoprene emissions generally produced over 50 percent of formaldehyde concentrations. Acetaldehyde retained the same patterns in production yields from biogenic NVOCs as January 2001. Terrain and its vegetation type affected how these contributions distributed among specific compounds in biogenic emissions.
The research presented here was performed under the Memorandum of Understanding between the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) and under agreement number DW13921548. Although it has been reviewed by EPA and NOAA and approved for publication, it does not necessarily reflect their policies or views.
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| PRESENTATION |
Cmaq Aerosol Module Development Recent Enhancements & Future Plans |
10/19/2004
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BHAVE, P., S. J. ROSELLE, F. S. BINKOWSKI, C. G. NOLTE, S. YU, G. L. GIPSON, AND K. L. SCHERE. Cmaq Aerosol Module Development Recent Enhancements & Future Plans. Presented at 2004 Models-3 Conference, Chapel Hill, NC, October 18 - 20, 2004.
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Recent enhancements to the CMAQ aerosol module will be reviewed briefly. These include revision of the secondary organic aerosol subroutine to improve numerical efficiency and control the growth of the accumulation mode standard deviation, revision of the nucleation subroutine to conserve sulfur mass, and development of a new coagulation subroutine to improve numerical efficiency.
Ongoing efforts to further improve the CMAQ aerosol module also will be discussed. These include the implementation of heterogeneous interactions with sea salt particles, dynamic mass transfer (instead of instantaneous equilibrium) of inorganic species between the gas and aerosol phases, and formation of solids in the inorganic aerosol system.
The research presented here was performed under the Memorandum of Understanding between the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) and under agreement number DW13921548. Although it has been reviewed by EPA and NOAA and approved for publication, it does not necessarily reflect their policies or views.
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