Near-realtime High Resolution U.S. Air Quality Predictions

ACOM together with RAL is now generating high-resolution, experimental, 48-hour forecasts of air pollutants across the contiguous United States. The predictions, which are freely available online, can help decision makers anticipate episodes of unhealthy air as well as accelerate research into the factors that influence air quality.

The system uses the Weather Research and Forecasting Model with Chemistry (WRF-Chem) at 12 km spatial resolution and displays expected concentrations of ozone, particulate matter and other trace gases at the surface as well as higher up in the altitude together with near-realtime observations of surface ozone and PM2.5 from the U.S. EPA Airnow network. The latter are also used for continuous evaluation of the system. The chemical boundary conditions are taken from ACOM’s global prediction system.

The forecasts have been supporting the multi-agency FIREX-AQ field campaign in July-August 2019 and in collaborations with the University of Huntsville, Alabama and the NASA TOLNET team are also providing guidance on the deployment of the network’s ozone lidars; in turn the lidar data are used for evaluating the predictions. 

Work on improving the forecasting system is ongoing. Planned activities include addressing a high bias in surface ozone in the Eastern U.S., enhancing the evaluation through comparison to meteorological observations and satellite derived NO2 TropOmi and CO from MOPITT, and adding data assimilation of satellite derived aerosol optical depth (AOD).

Figure 1. Animation of predicted and observed hourly surface ozone as displayed on the ACOM website. Use controls to play video and expand to full screen.


Figure 1
. Animation of predicted and observed hourly surface ozone as displayed on the ACOM website.