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Interpreting Predictions from the SAPRC07 Mechanism Based on Regional and Continental Simulations
Citation:
HUTZELL, W. T., D. J. LUECKEN, W. APPEL, AND W. P. Carter. Interpreting Predictions from the SAPRC07 Mechanism Based on Regional and Continental Simulations. ATMOSPHERIC ENVIRONMENT. Elsevier Science Ltd, New York, NY, 46(00):417-429, (2011).
Impact/Purpose:
The National Exposure Research Laboratory′s (NERL′s) Atmospheric Modeling and Analysis Division (AMAD) conducts research in support of EPA′s mission to protect human health and the environment. AMAD′s research program is engaged in developing and evaluating predictive atmospheric models on all spatial and temporal scales for forecasting the Nation′s air quality and for assessing changes in air quality and air pollutant exposures, as affected by changes in ecosystem management and regulatory decisions. AMAD is responsible for providing a sound scientific and technical basis for regulatory policies based on air quality models to improve ambient air quality. The models developed by AMAD are being used by EPA, NOAA, and the air pollution community in understanding and forecasting not only the magnitude of the air pollution problem, but also in developing emission control policies and regulations for air quality improvements.
Description:
The SAPRC07T mechanism is implemented and evaluated in the CMAQ air quality model. The implementation is described and tested with simulations over the United States for two periods. The evaluation compares results against observations for ozone and particulate matter as well as against predictions from the SAPRC-99 mechanism for the same simulation periods and model domain. Comparisons against SAPRC-99 results reveal largest differences over urban areas with low VOC to NOx ratios. Integrated rate analysis is used to investigate the chemical reactions responsible for these differences. Comparison against observations shows over predictions of ozone concentrations over the southeastern United States. The errors appear linked to failing to match the observations during early morning hours. We discuss the source of the errors in terms of both simulation inputs and the photochemical mechanism and recommend potential directions for improving applications with regional photochemical models.
URLs/Downloads:
Interpreting Predictions from the SAPRC07 Mechanism Based on Regional and Continental Simulations (PDF, NA pp, 4140 KB, about PDF)Atmospheric Environment
