CMAQv5.4 Paper

The current AQM version 7 (AQMv7) is coupled with an out-of-date CMAQ version 5.2.1. This release is created for a scientific paper in Geoscientific Model Development (GMD), where we have developed an updated AQMv7 by coupling to a ‘state-of-the-science’ CMAQ version 5.4. The updates include improvements in gas and aerosol chemistry, dry deposition processes, and structural changes to the Input/Output (IO) framework, enhancing IO computational efficiency and the air-surface exchange representation. In the paper, a test simulation in August 2023 was conducted to evaluate the changes in the model performance from the updates. Results show that the updated model demonstrates a significantly enhanced capability in simulating ozone (O3) in the contiguous United States (CONUS) by both reducing the positive bias during day and night, leading to a reduction of the mean bias by 50% and 72% for hourly and the maximum daily 8-hour average O3, respectively. Spatially, the new model lowers the positive bias of hourly O3 in all of the ten EPA regions, particularly within the southeastern and central US areas. Similarly, the updates induce uniformly lower fine particulate matter (PM2.5) concentrations across the CONUS domain, thus reducing the positive bias in the northeast and central Great Plain and exacerbating the negative bias in the west and south. The updated model has a very similar model performance for PM2.5 in the vicinity of fire emission sources as compared to AQMv7, thus indicating a focal point of model uncertainty and needed improvement. Despite these challenges, the study highlights the importance of the ongoing refinements for reliable air quality predictions from the UFS-AQM model, which is the future replacement of NOAA’s current operational air quality forecast system.

What's Changed

• update aqm_files.cmake with corresponding code changes in the local /… by @lwcugb in #15
• Add files via upload by @btang1 in #16
• Add files via upload by @btang1 in #17
• Feature/cmaq54 li by @lwcugb in #20

New Contributors

• @lwcugb made their first contribution in #15
• @btang1 made their first contribution in #16

Full Changelog: https://github.com/noaa-oar-arl/AQM/compare/795948c..CMAQ54_Paper