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SIMULATIONS OF AEROSOLS AND PHOTOCHEMICAL SPECIES WITH THE CMAQ PLUME-IN-GRID MODELING SYSTEM
Citation:
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.
Impact/Purpose:
The objectives of this task are to continuously develop and improve EPA's mesoscale (regional through urban scale) air quality simulation models, such as the Community Multiscale Air Quality (CMAQ) model, as air quality management and NAAQS implementation tools. 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.
Description:
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.