Aerosol Data Assimilation within JEDI for the NOAA’s Regional Air Quality Model (AQM)

The latest version of NOAA’s regional air quality forecast system was implemented and became operational on May 14, 2024. This system, referred to as AQM, has been developed through the online coupling of the atmospheric model with the Environmental Protection Agency (EPA)’s Community Multiscale Air Quality (CMAQ) model within the Unified Forecast System (UFS) framework. AQM is driven by the Global Forecast System (GFS) analysis and forecast products for meteorological initial and boundary conditions, the Global Ensemble Forecast System (GEFS) aerosol product for lateral boundary conditions of chemical species, various anthropogenic, biogenic, and fire emissions, as well as warm-start chemical initial conditions from a previous cycle without any constraints from aerosol measurements. The implementation of an aerosol data assimilation system can further enhance short-term air quality prediction skills by providing more accurate spatial analyses of initial aerosol species.

This presentation details the efforts to establish aerosol data assimilation capabilities for AQM by assimilating satellite retrievals of Aerosol Optical Depth (AOD) and in-situ measurements of particulate matter with diameter less than 2.5 micrometers (PM2.5). The ability to assimilate AOD and PM2.5 is developed within the Joint Effort for Data-Assimilation Integration (JEDI) framework. The Community Radiative Transfer Model (CRTM) AOD module functions as the observation operator for AOD assimilation. PM2.5 transformations are conducted through the JEDI Variable Derivation Repository (VADER). Currently, the control and analysis variables are individual aerosol species, whose background error statistics can either be static or follow dependent. The performance of the developing JEDI aerosol data assimilation system will be presented, along with a discussion of ongoing work.