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COMPARISON OF SPATIAL PATTERNS OF POLLUTANT DISTRIBUTION WITH CMAQ PREDICTIONS
Citation:
Phillips, S. B. AND P L. Finkelstein. COMPARISON OF SPATIAL PATTERNS OF POLLUTANT DISTRIBUTION WITH CMAQ PREDICTIONS. Presented at 2004 Models-3 Conference, Chapel Hill, NC, October 18-20, 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:
One indication of model performance is the comparison of spatial patterns of pollutants, either as concentration or deposition, predicted by the model with spatial patterns derived from measurements. If the spatial patterns produced by the model are similar to the observations in shape, location, and magnitude it can add to our confidence that the model is performing well. However, deriving spatial patterns from measured pollutant data is not always trivial. Modeling networks are spatially sparse, and frequently biased toward certain types of land use. There is also frequently measurement bias between networks. We will explore the development of reliable spatial models of monitoring data using a variety of simple approaches, and discuss the strengths and weaknesses of some of these. We will then compare the resulting spatial patterns with those predicted by CMAQ, noting similarities and differences. We will consider SO4, NO3, NH4 aerosols, and the wet deposition of SO4, No3, and NH4.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.