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EVALUATION TECHNIQUES AND TOOL DEVELOPMENT FOR FY 08 CMAQ RELEASE

Contact

http://cfpub.epa.gov/si/si_public_comments.cfm

Impact/Purpose:

The objective 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 truly validated. Static and Dynamic Operational, Diagnostic, and ultimately Probablistic evaluation methods are needed to both 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:

In this task, research efforts are outlined that relate to the AMD Model Evaluation Program element and support CMAQ releases within the FY05-FY08 time period. Model evaluation serves dual purposes; evaluation is necessary to characterize the accuracy of model predictions, and evaluation is needed to identify impacts and potential improvements in model inputs and modeled processes. This requires comparisons against observational data from a variety of perspectives, where analyses consider different spatial and temporal scales to assess model performance. Inter-relationships between different chemical species must also be considered as well as the influence of uncertainties in meteorological predictions and emission estimates. Several of the research efforts planned in FY05-08 will expand the current operational evaluation work to further evaluate CMAQ's ability to capture observed spatial and temporal variability. The model evaluation toolkit development included in this task will also help to diagnose the impact of meteorological uncertainties on the air quality predictions of ozone and aerosols. Several other evaluation research efforts described below are more diagnostic in nature, where tests are conducted to understand the contribution of individual processes or inputs on the predicted concentrations of policy relevant PM2.5 endpoints. The diagnostic evaluation work described includes the study of inorganic and organic carbon aerosols using diagnostic metrics and instrumented models and diagnostic sensitivity studies of input uncertainties for elemental carbon and ammonia emissions. Results from these diagnostic studies will contribute information for further CMAQ development and for improved emission inventories. In addition, several aspects of the diagnostic studies will directly contribute to the evaluation of CMAQ's ability to realistically predict to emission control scenarios, which is an essential component of evaluation needed by our clients in OAQPS.

Record Details:

Record Type:PROJECT
Start Date:10/01/2004
Projected Completion Date:09/01/2008
OMB Category:Other
Record ID: 113785