Unifying Regional and Global Atmospheric Composition Modeling for Operational Prediction at NCEP

Operational air quality predictions for the United States (U. S.) are provided at NOAA by the National Air Quality Forecasting Capability (NAQFC). NAQFC provides nationwide operational predictions of ozone and particulate matter. Predictions are produced twice per day (at 06 and 12 UTC cycles) at 12 km resolution and 1 hour time intervals through 48 hours and distributed at http://airquality.weather.gov. The NOAA National Centers for Environmental Prediction (NCEP) operational North American Mesoscale (NAM) 12 km weather prediction is used to drive the Community Multiscale Air Quality (CMAQ) model. Globally, NCEP runs an inline aerosol prediction system (the NEMS Global Aerosol Capability) at 1 degree horizontal resolution. Recently, NCEP with other NOAA labs and research communities has developed the Next Generation Global Prediction System (NGGPS) based on the Finite Volume Cubed Sphere core FV3 model as it Unified Forecasting System (UFS). FV3GFS is run at similar resolutions (13 km) to the NAM while mainly using the standard NCEP global model physics. Therefore, the transition to FV3 allows the unification of regional and global atmospheric composition predictions as well. This presentation will overview current capabilities and future plans for a unified atmospheric composition forecasting system.

In 2018, NOAA coupled simplified global aerosol chemistry (GOCART) to FV3GFS in an inline fashion and is currently testing regional air quality predictions driven by FV3GFS via offline coupling. This presentation will also evaluate the ability of FV3GFS and a higher resolution FV3Meso NWP model for predicting low level temperatures and capturing boundary layer processes important for driving air quality prediction. The NWP and air quality models will be evaluated for both summer and winter against standard and mesonet fields averaged for various regions. An evaluation of meteorological fields important to air quality modeling (eg: near surface winds, temperatures, moisture and boundary layer heights, cloud cover) will be reported on.