Establishment of a Community Modeling and Analysis Support Mechanism
William G. Benjey*
Atmospheric Sciences Modeling Division
Air Resources Laboratory
National Oceanic and Atmospheric Administration
Research Triangle Park, NC 27711
beni ev. william@epa. gov
Robert E. Imhoff
Director, Environmental Modeling Center of North Carolina
MCNC - Environmental Programs
P.O. Box 12889
Research Triangle Park, NC 27709-2889
rimhoff@emc.mcnc.org
ABSTRACT
During the fall of 2001, a Cooperative Research Agreement between the U.S. Environmental
Protection Agency and MCNC began a Community Modeling and Analysis System (CMAS) center.
The CMAS will foster development, distribution, and use of the Models-3/CMAQ (Community
Multiscale Air Quality) air quality modeling system. The CMAS is hosted by MCNC's Environmental
Modeling Center in Research Triangle Park, North Carolina. The objectives of the CMAS are to (1)
serve as a bridge between members of the Models-3/CMAQ modeling community, (2) encourage the
growth of the user community, (3) serve as an information clearinghouse for model applications,
emission modeling methods and data, (4) provide education about the models and their uses, (5)
maximize the scientific content and performance value of the Models-3/CMAQ system by encouraging
the expansion of the contributing developer community and taking advantage of multiple incremental
contributions, and (6) provide computer and skill resources to the Models-3/CMAQ modeling
community benefitting from economies of scale. Support and development work includes both
emission modeling (through the Sparse Matrix Operator Kernel Emission system) and the CMAQ
chemistry-transport modeling components. As a community modeling support center, the CMAS is
open to all interested participants. The center is organized into five functional parts: (1) Administration,
(2) Outreach, (3) Application Support, (4) Software Development, and (5) Modeling Research. The
model code accepted and released as a part of Models-3/CMAQ will be open and shared with all. The
External Advisory Committee, governing the CMAS policies and priorities, is a technically
knowledgeable group including representatives of state and regional agencies, EPA, industry,
consultants, academic institutions, and foreign users.
INTRODUCTION
Historically, advances in air quality model technology and data sets could not be easily shared
between modelers because of inconsistencies in specific pollutants addressed, scientific approach,
variables, and data formats. Over a decade ago, the U.S. Environmental Protection Agency (EPA)
recognized that an open source, modular code, unified chemistry ("one-atmosphere"), community
supported regional air quality modeling system might enable collaborative development and linking of
models for meteorology, air emissions, air quality chemistry and transport, hydrology, and
* On assignment to the National Exposure Research Laboratory, U.S. Environmental Protection Agency, Research Triangle
Park, NC 27711

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environmental and health effects.1 In response to the need, the EPA developed, and continues to
improve, the Models-3 Community Multiscale Air Quality (CMAQ) model system. The Models-
3/CMAQ system represented a new paradigm and anticipated the extensibility and power of geographic-
based grid modeling.2'3'4 Documentation for the chemistry and transport portion (CMAQ) of Models-
3/CMAQ is maintained at http://www.epa.gov/asmdnerl/models3 . Documentation for the emission
modeling part of the system, the Sparse Matrix Operator Kernel Emission (SMOKE) system is available
at http://www.emc.mcmc.org.
During the development of Models-3/CMAQ, EPA scientists recognized that support and
improvement of the system was too great a commitment of resources for any single organization, and
would be more effectively accomplished by a cadre of multiple model users and developers. A
workshop held during 1997 explored the methods and opportunities that might be followed to establish a
community support system. The proceedings are available at
http://www.emc.mcnc.org/CMAS/workshop draft.html. The workshop participants recommended that
collaborative community modeling include (1) representation from all categories of the user community,
(2) provision of user support, (3) well-documented, reviewed and tested open code, (4) a mechanism for
clear review and testing procedures for model improvements, (5) a means to enhance sharing of ideas
and data between Models-3/CMAQ modeling community members, and (6) inclusion of user-requested
model applications and research. Existing examples of community models were examined, including
two maintained at the University Corporation for Atmospheric Research, specifically the Mesoscale
Meteorology Model Version 5 (available at http://box.mmm.ucar.edu/mm5A) and climate model
(available at http://www.cgd.ucar.edu/cms/ccm3 ). EPA issued a competitive Request for Proposals for
a cooperative research grant to initiate a cooperative center for a Community Modeling and Analysis
System (CMAS). In October 2001, a four-year grant (November 2001-October 2005) was awarded to
the Environmental Modeling Center of MCNC in Research Triangle Park, North Carolina. The plan
under the grant is that CMAS will become self-sustaining by the end of the grant period through the
financial contributions of members and limited services. Modeling software and basic support will be
provided at no cost to the users. The EPA will assist the CMAS to the extent possible under the
cooperative research grant. EPA will continue to provide improvements to Models-3/CMAQ model
software, relevant data sets, and collaboration with EPA scientists facilitated by the grant Project
Officer.
CMAS OBJECTIVES
The purpose of CMAS is to provide technology transfer and support of Models-3/CMAQ for the
benefit of the air quality community. Planned activities, which will be phased in over the course of the
grant, include the following categories.
Outreach: A Bridge Between Users
A range of communication methods will be used to make CMAS information and products
widely available and to enhance communication between members of the community. For example,
participation in and the hosting of conferences for users is a key item in transfer of new information and
stimulation of ideas and collaboration. The information will be transferred to the community using:
website and list servers
•	conferences, seminars and workshops
•	technical working groups
•	input from the CMAS External Advisory Committee (EAC)
printed and electronic materials

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collaboration with professional groups
technical reports
newsletters
• site visits
Providing a central point of contact between users will allow the creation and direction of large projects
distributed across multiple organizations.
Growth of the User Community
The development of the user community and encouragement of collaborative efforts is the
principal initial effort in establishing CMAS. The two main user groups are those interested in
regulatory applications and those pursuing the scientific underpinnings of air quality modeling. These
include state, federal and regional government entities, regional planning bodies, the private sector
(contractors and industry), and universities.
Clearinghouse
Many air quality modeling data sets have value for reuse or for comparison between modelers.
The availability of these data is often ad hoc and depends on mutual awareness of modelers and their
projects. The CMAS will serve as a clearinghouse for model-related data sets, without replicating the
archival of relevant data sets held elsewhere. For example, CMAS might archive significant model
output data sets or special input files, but not emission inventory data routinely available from the EPA
Chief web site.
The CMAS will also act as the clearinghouse for future (after 2002) Models-3/CMAQ releases.
Major releases of Models-3/CMAQ should continue on an approximately annual basis. A bug tracking
feature, similar to that used for MM5 will be used to help users keep track of model revisions during the
interim. Acceptance of new modules into Models-3/CMAQ will be based on science and testing criteria
determined by the EAC.
Education
The CMAS will serve as an educational center for the user community by offering training and
user support via a help desk, e-mail mailing lists, and web page information. These services will be
developed and enhanced through time to reflect user needs. Training will be emphasized, and will
include air quality modeling applications, data preparation for modeling, building of interchangeable
modeling components, and evaluation of model configurations. Centralizing the development of courses
will allow member groups to offer training that is consistent, complete, and up-to-date without having to
independently develop and update the material.
Maximize Value of Content by Leveraging Many Partners
The CMAS will follow the priority needs and objectives expressed by the user community in supporting
and improving Models-3/CMAQ. Because there are many users who may contribute, CMAS will
ensure that the resulting modeling services and products represent the best value added in return for the
contributions CMAS community members. Each member of the community will benefit from the
compounding of the scientific and financial contributions of the group. This may best be done by
focusing pooled resources on those priorities of highest community need, as expressed by the CMAS
External Advisory Committee (EAC). Although CMAS model code and documentation will be freely

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available to the public, those users becoming contributing members of the CMAS will benefit from the
compound result of many members contributing to the cost of model support and development, as well
as having a greater claim in the setting of priorities. A membership and financial structure will be
established that allows the CMAS to become self-sufficient within four years. Membership structure is
still to be determined. One possibility is to have a tiered membership structure. Memberships could
include Sponsoring Institutions (agencies able to support the CMAS through grants), CMAS Members (a
range of levels of participation and benefits to maintain common services, each with an annual fee),
Granting Institutions (agencies support via competitive research grants), Regional Consortia (groups of
states or agencies), and Individual Organizations.
Provision of Computer and Science Skills
The CMAS will develop advanced tools to assist users to build models, develop data sets, analyze
results, and understand model behavior. The needed tools will be prioritized by the community through
the EAC, and developed within the CMAS center and by the community as a whole. CMAS model
products, data sets, and model support will be available to the community at no cost. With the consent
of the community, the CMAS may provide limited consulting services to users for specific model
applications. Often, model applications or data set processing are tasks of sufficient size that some users
cannot handle them with in-house resources, yet it is not cost effective to contract out to a for-profit
firm. Types of projects that the CMAS could assist in are: input data preparation (emissions,
meteorology, and other model inputs), model configuration and application for the evaluation of new
science, model configuration and application for state or tribal regulatory purposes or impact assessment,
and analyses of modeling studies (operational and diagnostic evaluation through graphical and statistical
measures).
CMAS ORGANIZATION
The CMAS is counseled by the EAC, a technically knowledgeable group that guides CMAS in
meeting the needs of the community. The EAC acts on behalf of the Models-3/CMAQ modeling
community to define needs and priorities, advise on changing requirements, set research and
development priorities, review progress of activities, and make recommendations for the advancement of
Models-3/CMAQ science and software. The EAC membership consists of three representatives of state
air quality agencies, two representatives of industry, two representatives of academic research
institutions, three members of the Models-3/CMAQ air quality consulting community, two members of
regional air quality planning bodies, one Canadian member, one representative of the balance of the
international user community, one ex officio representative of EPA regional offices, and one ex officio
representative each from three other involved EPA offices (Table 1). EPA will participate with other
EAC members as a partner in the CMAS. New and updated Models-3/CMAQ-related products from
EPA will be provided to CMAS, as well as technical information and coordination on modeling products
under development by EPA. The EAC members will serve staggered two-year terms with some
memberships ending every six months. Monthly conference calls are planned, along with an annual
meeting and working sessions held in conjunction with other conferences and meetings. The EAC is
creating its operating bylaws, defining review and test procedures for the incorporation of new or revised
model code into CMAQ, and establishing operating priorities for all CMAS objectives and functions.
Table 1. External Advisory Committee members to date.
Com in ii 11 ilv Represented
Representative
Affiliation
EPA (OAQPS)
Mr. Mark Evangelista
Emissions, Monitoring and Analysis
Division

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| C'oiiiilliiiiil> Represented |
| Uepresenliilive |
| AITilhilion |
EPA (ORD)
Mr. Kenneth Schere
Atmospheric Modeling Division
EPA (OEI)
Dr. Darrell Winner
Office of Environmental Analysis and
Access
EPA (Regions)
Mr. Alan Cimorelli
EPA Region 3
State Agency
Mr. Peter Breitenbach
Texas Natural Resource Conservation
Commission
State Agency
Dr. Kaduwela Ajith
California Air Resources Board
State Agency
Ms. Sheila Holman
North Carolina Dept. of Health,
Environment, and Natural Resources
Industry
Dr. David Chock
Ford Motor Company
Industry
Dr. Alan Hansen
Electric Power Research Institute
University
Dr. Harvey Jeffries
University of North Carolina
University
Dr. Daewon Byun
University of Houston
Consultants
Mr. Ralph Morris
Environ, Inc.
Consultants
Dr. Christian
Seigneur
AER Consultants, Inc.
Regional Planning Organization
Mr. Mike Koerber
Lake Michigan Air Directors Consortium
Regional Planning Organization
Dr. John Vimont
Western Regional Air Partnership
International
Dr. Richard Derwent
United Kingdom
Canada
Dr. Weimin Jiang
National Research Council of Canada
Expert Users
Dr. Neil Wheeler
Sonoma Technology
The functions of CMAS are grouped into five general areas, with appropriate links to the EAC
and air quality modeling community as a whole. The functions include CMAS administration, outreach,
modeling research, development and model applications (Figure 1). The core CMAS staff is organized
around these functions, and now consists of a portion of the time of five people, with the balance of the
MCNC Environmental Division staff available on an as-needed basis. The CMAS Director is Mr.
Robert Imhoff, who also serves the co-Outreach Coordinator with Dr. Adel Hanna. The Research
Coordinator is Dr. Rohit Mathur, the Software Development Coordinator is Ms. Alison Eyth, and the
Applications Support Coordinator is Mr. Zachariah Adelman. The duties of each position are
summarized below.
CMAS Director (Administration")
Coordination of CMAS activities
Responsible for achievement of milestones
Convening of the External Advisory Committee

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Outreach Coordinator
Identification and development of user clientele
Communication of CMAS value and benefits
Encouragement of collaborations (identifying collaboration opportunities and funding
possibilities
Research Coordinator
Verification of scientific review of Models-3/CMAQ changes
Reporting of testing and evaluation
Coordination of research activities
Establish dialog with research community to set research agenda
Research on linkages to other modeling systems
Software Development Coordinator
Track requests for model changes through code change and testing process
Document procedures for configuration management, benchmark testing and documentation for
the EAC.
Implement software for tracking and authenticating model versions and options used for each
application
New tool development
Improvements to the I/O API (data convention in Models-3/CMAQ)
Parallelization of CMAQ code
Coupling to other models (ecosystem, etc)
Figure 1. Relationship of CMAS functional areas.
External Advisory
Committee
Administration
Air Quality Community
Outreach
Research
Applications
Development

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Applications Support Coordinator
Directs user support
Help Desk
Training course development and delivery
Computing resources
Shared-data clearinghouse
Application consulting
Model testing and integration
Integration of alternative modules
Porting and benchmark testing of alternative modeling platforms
RESEARCH AND REGULATORY MODELING
The science underlying Models-3/CMAQ is progressing quickly. Therefore, the software code
must be frequently updated to reflect advances in scientific understanding and computational methods.
With active air quality modeling community involvement, it is likely that scientists will create variations
of different CMAQ modules and features for research purposes. The CMAS would incorporate these
innovations on a continuing basis following a definite review and testing procedure. For regulatory
modeling, the U.S. EPA Office of Air Quality and Standards shall retain approval authority over model
versions, combinations of components, and model setting alternatives acceptable. The general review
and approval cycle of model changes is outlined in Figure 2.
Figure 2. General CMAS software change review and approval process.
New Science
i	Regulatory
Requirement
External
Science Review
1 r
Version
Proposed
Changes
CMAS Test
And
Evaluation
EPA
Regulatory
Office
CMAS
EAC
Recommendations
C MAS/EPA
Integration,
Code Review, &
Documentation
Official Science
Version(s)
Official
egulatorv Version

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PLANS FOR INITIATION OF SERVICES
During the first year (2002) of the CMAS, the principal activities include the establishment and
creation of the structure and operating procedures of the EAC, planning and implementation of the
means for eventual self-sufficiency of the CMAS, definition and implementation of the cost and
membership structure, and implementation of model support. A comprehensive model support structure
will be a major benefit to the modeling community. Models-3/CMAQ releases during 2002 will
continue through EPA, and thereafter by CMAS.
During the second year of operation, the cooperative research grant, CMAS plans to provide
releases of Models-3/CMAQ changes, model documentation, user training, and begin a model data
clearing house. EPA will provide relevant new development to CMAS during this period. In addition to
improvements in the chemical transport model portion of the Models-3/CMAQ system, the emission
modeling portion of the system (the Sparse Matrix Operator Kernel Emission or SMOKE), will be
maintained and improved. The SMOKE was developed by the MCNC under an EPA cooperative
research grant.5'6 In addition, a new Java® language based modeling framework and interface has been
developed by EPA for use with multi-media modeling applications. The framework, called the
Multimedia Integrated Modeling System (MIMS), will be applied to Models-3/CMAQ and SMOKE, and
will be maintained for air quality modeling purposes by CMAS. Information about MIMS is located on
the Internet at http://www.epa.gov/asmdnerl/mims/. Coordinated support of these model software
systems will provide users with a "one-stop" help center. Other participants in CMAS will also make
software contributions to the Models-3/CMAQ system. To the extent that additional funding is available
from sponsors or members of CMAS, these functions may be accelerated or expanded, or research
functions begun. The third and fourth years of operation will continue, and hopefully expand, the above
functions, depending upon the level of resources available to CMAS.
CONCLUSIONS
The CMAS provides a clear, organized, opportunity for the members of the air quality modeling
community to collaborate and leverage the potential of their combined resources in a open, shared
modeling system, following the overall priorities of the modeling community. CMAS allows the
modeling system results to truly be greater than the sum of the efforts of the individual members of the
community. Pooling of resources and science advances will allow for more rapid advances in modeling,
more sound, rapid and economical model applications, and for a more knowledgeable community of
people using the model and consuming model information.
DISCLAIMER
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.
REFERENCES
1.	Novak, J.H.; Dennis. R.L.; Byun, D.W. Pleim, J.E.; Galluppi, K.J.; Coats, C.J.; Chall, S.; Vouk, M..A.
EPA Third Generation Air Quality Modeling System: Volume 1: Concept, U.S. Environmental
Protection Agency, Office of Research and Development, Research Triangle Park, NC, 1995; EPA-
600/R-95/082, 243 pp.
2.	Appleton, E.L. "Air Quality Modeling's Brave New World", Environmental Science and Technology
1996, 30, 5, pp. 200A-204A.

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3.	Reichardt, T. "Environmental GIS: The World in a Computer", Environmental Science and
Technology 1996, 30, 8, pp. 340A-344A.
4.	Byun, D.W.; Ching, J.K.S., Eds.; Science Algorithms of the EPA Models-3 Community Multiscale Air
Quality (CMAQ) Modeling System, U.S. Environmental Protection Agency, Office of Research and
Development, Washington, D.C., 1999; EPA/600/R-99/030, 1051 pp.
5.	Houyoux, M.R.; Vukovich, J.M.; "Updates to the Sparse Matrix Operator Kernel Emissions
(SMOKE) Modeling System and Integration with Models-3". In Proceedings of the Emission Inventory
Conference: Regional Strategies for the Future, Proceedings of a Specialty Conference, Air and Waste
Management Association: Pittsburgh, PA, 1999, pp. 430-440.
6.	Houyoux, M.R.; Adelman, Z. "Quality Assurance Enhancements to the SMOKE Modeling System",
Presented at the Emission Inventory Conference of the U.S. Environmental Protection Agency: One
Atmosphere, One Inventory, Many Challenges, Raleigh, NC, May 2001; 12 pp.

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KEY WORDS
air quality modeling
Models-3
CMAS
CMAQ
SMOKE
MIMS
community model

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3. REPORT TYPE AND DATES COVERED
4. TITLE AND SUBTITLE:
Establishment of a Community Modeling and Analysis Support mechanism
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6. AUTHOR(S)
W.G. Beniev* and R. E. Imhoff
7. PERFORMING ORGANIZATION NAMES(S) AND ADDRESS(ES)
Nat'l Exposure Research Lab., ORD, U.S. EPA
Research Triangle Park, N.C. 27711
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REPORT NUMBER
9. SPONSORING/MONITORING AGENCY NAME(S) AND
ADDRESS(ES) *National Exposure Research Laboratory -RTP, NC
ORD, U.S. EPA, Research Triangle Park, N.C. 27711
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REPORT NUMBER
EPA/600/A-03/045
11. SUPPLEMENTARY NOTES
12a. DISTRIBUTION/AVAILABILITY STATEMENT
Release to the General Public
12b. DISTRIBUTION CODE
EPA/600/9
13. ABSTRACT (Maximum 200 words)
During the fall of 2001, a Cooperative Research Agreement between the U.S. Environmental and MCNC began a Community Modeling
and Analysis System (CMAS) center. The CMAS will foster development, distribution, and use of the Models-3/CMAQ (Community
Multiscale Air Quality) air quality modeling system. The CMAS is hosted by MCNC's Environmental Modeling Center in Research
Triangle Park, North Carolina. The objectives of the CMAS are to (1) serve as a bridge between members of the Models-3/CMAQ
modeling community, (2) encourage the growth of the user community, (3) serve as an information clearinghouse for model applications,
emission modeling methods and data, (4) provide education about the models and their uses, (5) maximize the scientific content and
performance value of the Models-3/CMAQ system by encouraging the expansion of the contributing developer community and taking
of multiple incremental contributions, and (6) provide computer and skill resources to the Models-3/CMAQ modeling community
benefitting from economies of scale. Support and development work includes both emission modeling (through the Sparse Matrix
Operator Kernel Emission system) and the CMAQ chemistry-transport modeling components. As a community modeling support center,
the CMAS is open to all interested participants. The center is organized into five functional parts: (1) Administration, (2) Outreach,
(3) Application Support, (4) Software Development, and (5) Modeling Research. The model code accepted and released as a part of
Models-3/CMAQ will be open and shared with all. The External Advisory Committee, governing the CMAS policies and priorities, is a
technically knowledgeable group including representatives of state and regional agencies, EPA, industry, consultants, academic
institutions, and foreign users.
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A03
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