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DEVELOPMENT AND APPLICATION OF THE CMAQ PLUME-IN-GRID MODEL
Citation:
GODOWITCH, J. M. DEVELOPMENT AND APPLICATION OF THE CMAQ PLUME-IN-GRID MODEL. Presented at 4th Annual CMAS Models-3 User's Conference, Chapel Hill, NC, September 26 - 28, 2005.
Impact/Purpose:
The objectives of this task are to develop, improve, and evaluate EPA's Community Multiscale Air Quality (CMAQ) model, as an air quality management and NAAQS implementation tool. CMAQ is a multiscale and multi-pollutant chemistry-transport model (CTM) that includes the necessary critical science process modules for atmospheric transport, deposition, cloud mixing, emissions, gas- and aqueous-phase chemical transformation processes, and aerosol dynamics and chemistry. To achieve the advances in CMAQ, research will be conducted to develop and test appropriate chemical and physical mechanisms, improve the accuracy of emissions and dry deposition algorithms, and to develop and improve state-of-the-science meteorology models and contributing process parameterizations.
The model will be tested and evaluated to thoroughly characterize the performance of the emissions, meteorological and chemical/transport modeling components of the CMAQ 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 truly validated. Both operational and diagnostic evaluations, together with sensitivity analyses are needed to both establish credibility and build confidence within the client and scientific community in the simulation 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 poster depicts the dynamic and chemical processes simulated by the Plume-in-Grid (PinG) model, which is fully integrated in the Community Multiscale Air Quality (CMAQ) Eulerian grid model. An example set of plume section paths during the subgrid phase is displayed within a model test domain. Selected PinG model simulation results are also presented of ozone and aerosol sulfate concentrations within subgrid scale plumes. Excess ozone and sulfate are generated above background levels downwind of the major point sources with generally more sulfate above background formed in the lower NOx source plumes. Results from a model application for a continental domain with a 36km grid cell size are also shown from model runs with and without the PinG approach for a particular day from the July 2001 modeling period.