Smoke Particles/Chemical Data Assimilated in High Res. Real-Time Forecasts

On Saturday 26 May 2012, a narrow plume of fine particle smoke was transported by strong winds from the Whitewater-Baldy fires in New Mexico northward over Colorado where it mixed down to the surface. Satellite data and observational reports revealed that a hazy, brown cloud of fine particles plagued the Colorado Front Range during the first part of the Memorial Day weekend. The real-time HRRR-Chem numerical forecast produced at NOAA/ESRL/GSD did remarkably well at capturing the narrow plume of fine particles from the New Mexico fires and its impact on Colorado regional air quality due to the inclusion of wildfire smoke emissions and chemical data assimilation.

Background: The HRRR-Chem is an experimental real-time 3-km resolution, hourly updated, cloud resolving, inline air quality forecast model. In the forecasts, the smoke from satellite-observed wildfires (WF-ABBA and MODIS) is included using the GOCART aerosol scheme, and particles interact with the regional meteorological forecast via absorption and reflection of downward shortwave radiation. The initial fine particle aerosols for the forecast are generated using previous forecast data along with chemical data assimilation via the Gridpoint Statistical Interpolation (GSI) methodology. During the chemical data assimilation segment, observations from over 380 cities across the lower 48 United States are used to refine the previous six-hour three-dimensional weather/particle forecast fields. This is one of the first NOAA models to include chemical data assimilation in real-time forecasts and so far it has demonstrated a significant improvement in fine particulate matter forecasts.

Significance: The 2009 NOAA Science Advisory Board as well as the 2012 NOAA/US Forest Service research Memorandum Of Understanding highlighted the need for coupled wildfire-meteorological forecast models to better understand the impact wildfires have on the local fire suppression support, regional air quality, and aviation interests. The work to include wildfire smoke into real-time forecasts, as well as its interaction with the weather, addresses this challenge. In addition, advances in chemical data assimilation in real-time forecasts relates to NOAA's Climate and Weather goals by enhancing the understanding of radiatively important fine-particle aerosols as well as improving air quality forecast models.

Contributing ESRL scientists include Steven Peckham, Tanya Smirnova, Georg Grell, and Mariusz Pagowski of NOAA/ESRL/GSD, and Stuart McKeen of NOAA/ESRL/CSD.

Contact information
Name: Steven Peckham
Tel: 303-497-7978