NOAA's operational air quality predictions

The National Air Quality Forecasting Capability (NAQFC) provides operational predictions of ozone and wildfire smoke nationwide and operational predictions of airborne dust from dust storms over the contiguous 48 states. Predictions are produced beyond midnight of the following day at 12km resolution and 1 hour time intervals and are distributed in numerical format and in graphical format at http://airquality.weather.gov/. Ozone predictions combine the NOAA National Centers for Environmental Prediction (NCEP) operational Nonhydrostatic Mesoscale Model on Arakawa B-grid (NMMB) weather predictions with inventory based emissions estimates from the EPA and chemical processes within the Community Multiscale Air Quality (CMAQ) model. The Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model is used to provide standalone predictions of wildfire smoke and dust storm predictions, both of which have highly variable intermittent sources. Smoke sources are based on NOAA/NESDIS analysis of satellite imagery for detection of smoke source locations that is combined with US Forest Service's BlueSky framework to estimate smoke emissions. Dust source locations are based on satellite climatology of the frequency of dust emissions. Dust is emitted in the model when threshold velocity is exceeded and the emissions are modulated by real time estimates of soil moisture. Routine verification of ozone relies on AIRNow compilation of observations from surface monitors, whereas verification of smoke and dust predictions relies on satellite retrievals of smoke and dust column integrals.

Dust predictions were implemented in 2012, followed by an implementation of a longer time step to reduce run time for those predictions under a heavy dust loading. Emissions used in ozone prediction have been updated starting with summer of 2012 to include projected changes in emissions from mobile sources for 2012, reducing NOx emissions and ozone overestimation, especially in the eastern US. With the transition to a new computing platform in 2013, smoke predictions were updated to include an increase in maximum smoke plume rise (up to 1.25 times the planetary boundary layer depth), a decrease in wet removal of particles, and a modification in daily cycling of smoke emissions. Impacts of an automated algorithm for detection of locations of wildfire smoke emissions in Canada and Mexico are being evaluated in smoke predictions. Overview of air quality predictions will be presented with a discussion of recent updates to emissions.