Forecasting Source Impacts for Georgia
Updated from the HiRes system, the HiRes2 air quality forecasting system has been in operation at Georgia Tech since November 2014. The system uses WRF3.6 and CMAQ5.0.2 with SAPRC07TC mechanism, AERO6 aerosol module, inline BEIS biogenic emissions and inline 3-D point source emissions processing and has based its emissions projection on 2011 NEI. In addition to providing air quality concentration e.g. O3 and PM2.5 forecasts, it also forecasts air quality impacts from sources such as power plants and traffic (on-road motor vehicles) by utilizing the DDM-3D technique that has been integrated into CMAQ5.0.2. The source impacts usually show significant differences in their spatial patterns. For example, traffic emissions tend to dominate contribution to PM2.5 at local scales while power plants extend their impacts to long distances. The system also forecasts prescribed burn (PB) impacts, which can be significant in winter and spring.
To improve the accuracy of forecasting, in HiRes2 system, the emissions are continuously "corrected" by near real-time observations. The DDM-3D sensitivities are used in an inverse modeling context to improve forecasting performance. By utilizing the observations during the last 7 days, the emissions are adjusted to reduce the biase in the foercast and are used for the next 7 days. Currently, the observations used in this process are ground level measurements of PM2.5 averaged to daily values. The satellite retrievals from NASA MODIS collection 6 AOD products and ground level measurements of other pollutants will also be used in inverse modeling.
This project is funded by Georgia EPD, USEPA and by NASA through the Air Quality Applied Science Team program.