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RESULTS OF PHOTOCHEMICAL SIMULATIONS OF SUBGRID SCALE POINT SOURCE EMISSIONS WITH THE MODELS-3 CMAQ MODELING SYSTEM
Citation:
Godowitch, J M. RESULTS OF PHOTOCHEMICAL SIMULATIONS OF SUBGRID SCALE POINT SOURCE EMISSIONS WITH THE MODELS-3 CMAQ MODELING SYSTEM. Presented at Millenium Symposium on Atmospheric Chemistry, Albuquerque, NM, January 14-19, 2001.
Impact/Purpose:
The objectives of this task are to continuously develop and improve the Community Multiscale Air Quality (CMAQ) modeling system, which is the science implementation within the Models-3 system framework for air quality simulation. 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. It relies on Models-3 I/O API to support machine independent data access and maintains simple interfaces among science processor modules to provide a high-level of modularity.
Description:
The Community Multiscale Air Quality (CMAQ) / Plume-in-Grid (PinG) model was applied on a domain encompassing the greater Nashville, Tennessee region. Model simulations were performed for selected days in July 1995 during the Southern Oxidant Study (SOS) field study program which was conducted in the Nashville area. In particular, five major point sources exhibiting a range of Nox emission rates were selected for the PinG treatment. Selected PinG model concentrations and representative examples of the initial results of an ongoing evaluation of the PinG model with the SOS/Nashville data are presented to provide a preliminary demonstration of the capability of the CMAQ/PinG approach. In particular, modeled concentrations of ozone, SO2, and nitrogen oxides are compared to plume data collected during horizontal traverses by an instrumented helicopter and research aircraft across different plumes. Statistical results are also provided at 40 km downwind of the largest point source. The comparisons and quantitative results are encouraging as PinG exhibited the capability to realistically simulate the observed photochemical evolution for ozone and other species at various downwind distances for these cases.