National Air Quality Forecast Capability: Status and Research Needs

Abstract:

Operational air quality predictions for the United States (U. S.) are provided by National Air Quality Forecasting Capability (NAQFC), which is being built by NOAA in partnership with the U.S. EPA. NAQFC provides nationwide operational predictions of ozone, smoke from wildfires, as well as dust from dust storms for the contiguous 48 states. Predictions are produced beyond midnight of the following day at 12 km resolution and 1 hour time intervals and distributed at http://airquality.weather.gov.

Ozone predictions and developmental testing of aerosol predictions combine the NOAA National Centers for Environmental Prediction (NCEP) operational North American Mesoscale (NAM) weather predictions with the Community Multiscale Air Quality (CMAQ) model. Predictions of smoke and dust storms use the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model. Routine verification of ozone and developmental aerosol predictions relies on AIRNow observations, whereas smoke and dust predictions rely on satellite retrievals.

Recent updates to operational ozone prediction at NOAA have focused on mobile emissions, which were updated using the projections of mobile sources for 2012. Satellite and ground observations were used to derive NOx trends, which were compared with the emissions data used by NAQFC indicating improved agreement over large metropolitan areas in the US. Updates to the chemical mechanism are being tested for operational implementation.

Recent testing of PM2.5 predictions is relying on National Emission Inventory (NEI) inputs augmented by real time sources from wildfires and dust storms. Testing of PM2.5 predictions continues to exhibit seasonal biases – overprediction in the winter and underprediction in the summer. Current efforts are focusing on inclusion of bias correction and development of linkages with global atmospheric composition predictions.