92nd American Meteorological Society Annual Meeting (January 22-26, 2012)

Tuesday, 24 January 2012: 2:15 PM
Expansion of NOAA's National Air Quality Forecast Guidance
Room 342 (New Orleans Convention Center )
Ivanka Stajner, NOAA/NWS/OST, Silver Spring, MD; and P. Lee, J. T. Mcqueen, R. Draxler, G. Manikin, K. Wedmark, and T. McClung

The National Oceanic and Atmospheric Administration (NOAA) has produced forecast guidance for surface ozone concentrations and smoke concentrations throughout the lower 48 states (CONUS) since 2007. Ozone and smoke forecast guidance have been expanded to Alaska and Hawaii by 2010. These predictions are made in partnership with the US Environmental Protection Agency (EPA) and US Forest Service. Operational forecast guidance is available on the web at http://www.weather.gov/aq/, and experimental guidance at http://www.weather/gov/aq-expr. We present examples of evaluation of recent performance of ozone and smoke predictions, including ozone predictions during the heat wave in the northeast in July 2011 and smoke predictions during immense Wallow, Arizona fire during June 2011.

NOAA's hour by hour forecast guidance at 12 km grid resolution out to 48 hours shows when and where predicted values of ozone and smoke are expected to reach harmful levels in cities, suburbs, and rural areas. Ozone forecasts are produced with a linked numerical prediction system run operationally at the National Centers for Environmental Prediction (NCEP) supercomputing facility: North American Mesoscale (NAM) weather predictions are used in the Community Multiscale Air Quality (CMAQ) model. The next upgrade of operational NAM, to the Non-hydrostatic Mesoscale Model on Arakawa B grid (NMM-B), is planned in 2011. Therefore, NOAA modified the coupling of NAM to CMAQ: first with a minor adaptation of CMAQ's vertical structure to that of NMM-B, to be followed by a new version of CMAQ on the rotated longitude-latitude NMM-B grid. Use of the B-grid in CMAQ will facilitate tighter horizontal coupling between the meteorological and air quality models and it is expected to improve fidelity of air quality predictions at higher horizontal resolution.

NWS is developing capabilities for quantitative predictions of fine particles (PM2.5). Several challenges are being addressed: (1) Inclusion of intermittent sources. Predictions of PM2.5 from inventoried emissions show substantial seasonal biases that are consistent with missing intermittent sources in the summertime. Smoke from wildfires, and airborne dust are being tested and implemented as components. Standalone experimental testing of dust predictions over CONUS relies on source regions with dust-emissions potential that are estimated from climatology of satellite-observed dust events during 2003-2006 and real time information on surface moisture. When surface winds exceed entrainment thresholds, dust is emitted and transported by the HYbrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model driven by NAM meteorology to predict surface and column dust concentrations. Long-range transport of dust impacting CONUS domain is being incorporated through boundary-conditions to help capture events like springtime Asian dust transport and summertime trans-Atlantic transport of Saharan dust. (2) Real-time ingestion of observations. Smoke predictions are based on satellite observations of location and extent of wildfires. Assimilation of surface measurements of the fine particles (PM2.5) is being tested to reduce biases in predicted surface concentrations of PM2.5. (3) Chemical mechanisms for inventory-based predictions. More comprehensive chemical mechanisms are needed to account for reactive chemical transport and secondary formation of aerosols from pollutants.

NWS' air quality forecast guidance, experimental and developmental products are being evaluated and tested with a focus group of state and local air quality forecasters. NWS forecasters at the Weather Forecast Offices and NCEP are also encouraged to share their weather expertise and coordinate with their corresponding state and local air quality forecasters.

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