Citation:

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.

Impact/Purpose:

The goal of this task is to thoroughly characterize the performance of the emissions, meteorological and chemical/transport modeling components of the Models-3 system, with an emphasis on the chemical/transport model, CMAQ. Emissions-based models are composed of highly complex scientific hypotheses concerning natural processes that can be evaluated through comparison with observations, but not validated. Both performance and diagnostic evaluation together with sensitivity analyses are needed to establish credibility and build confidence within the client and scientific community in the simulations results for policy and scientific applications. The characterization of the performance of Models-3/CMAQ is also a tool for the model developers to identify aspects of the modeling system that require further improvement.

Description:

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 , PM_2.5 , 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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