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Regional and hemispheric evaluation of the new Community Multiscale Air Quality Model (CMAQ) version 5.3
Citation:
Appel, Keith, C. Hogrefe, K. Foley, B. Murphy, H. Pye, G. Sarwar, J. Bash, J. Pleim, AND R. Mathur. Regional and hemispheric evaluation of the new Community Multiscale Air Quality Model (CMAQ) version 5.3. 2019 Meteorology and Climate - Modeling for Air Quality Conference, Davis, California, September 11 - 13, 2019.
Impact/Purpose:
This work presents an evaluation of the latest release of the Community Multiscale Air Quality (CMAQ) model. The CMAQ model is a state-of-the-science air quality model used across the globe to perform air quality modeling for regulatory impact assessments, scientific studies and air quality forecasting. Every new release of the CMAQ model is thoroughly evaluated to provide the community with important information regarding model updates and significant changes in model performance that can be expected when using the new model. Presentations such as this provide an opportunity to share the evaluation results with the scientific community and stakeholders so they know how best to apply the new model.
Description:
In the summer 2019, the United States Environmental Protection Agency (USEPA) will release the latest version of the Community Multiscale Air Quality (CMAQ) model. This latest version of the CMAQ model, 5.3, includes a wide range of scientific and structural updates to the current version of the model released several years ago. Examples of these updates include a new version of the aerosol module (AERO7), which improves the simulation of secondary organic aerosol (SOA) particle formation in the atmosphere. Dimethyl sulfide (DMS) chemistry has also been added as an available option in v5.3. The detailed halogen chemistry available in CMAQv5.2.1 has been updated and is now compatible with the CB6r3 chemical mechanism. The simple halogen chemistry available in CMAQv5.2.1 has also been updated. The M3DRY deposition scheme has been updated to improve the deposition of gases and bi-directional exchange of ammonia at the surface. A new dry deposition scheme, the Surface Tiled Aerosol and Gaseous Exchange (STAGE), is also available for the first time in CMAQv5.3. STAGE allows for land-use specific dry deposition estimates which are very important for terrestrial and aquatic ecosystem health applications. A comprehensive evaluation of the new model using observations from the Northern Hemisphere and contiguous United States will be presented, comparing the new model version to the previous model version and to observations, focusing primarily on the performance of ozone and particulate matter.