Advancements in Operational CMAQ MODIS AOD data-assimilation at Baron Advanced Meteorological Systems

Baron Advanced Meteorological Systems (BAMS) has been engaged in operational numerical air quality prediction (NAQP) for well over a decade. Recently, under a NASA grant, an observation-space variational data-assimilation sub-system was developed and implemented to provide the CMAQ model with remotely sensed aerosol information. The initial CMAQ-DA was run offline for approximately a year, showing good promise in some areas of the country, but more equivocal results in others. Detailed examination of the results suggested that improvements could be made by utilizing available surface PM2.5 observations within the assimilation system. This approach was implemented and based on significant improvements in the cycled-analysis model, forecast runs were then initiated. This talk will describe improvements to the DA subsystem and quantitative improvements in day-1 and day-2 24-hr average surface PM2.5 forecast results as compared to the non-data-assimilating CMAQ forecast model. BAMS expects the new CMAQ-DA to become routinely available to clients and customers in the near future.