EOMF-02. Development of Global Aerosol Forecast Model (GEFS-Aerosols) into NOAA’s Unified Forecast System (UFS)

Abstract
NOAA’s National Weather Service (NWS) is on its way to deploy various operational prediction applications using the Unified Forecast System (https://ufscommunity.org/), a community-based coupled, comprehensive Earth modeling system. A chemical component developed in collaboration among the Global Systems Laboratory (GSL), Chemical Science Laboratory (CSL), and Air Resource Laboratory (ARL) was coupled online with the FV3 Global Forecast System (FV3GFS) using the National Unified Operational Prediction Capability (NUOPC)-based NOAA Environmental Modeling System (NEMS) software. It replaced the previous operational global aerosol prediction NEMS GFS Aerosol Component (NGAC) system on September 24th, 2020 as an ensemble member in the operational Global Ensemble Forecast System version 12 (GEFSv12), named GEFS-Aerosols. This chemical component of atmospheric composition in GEFS-Aerosols is based on WRF-Chem with aerosol modules based on the Goddard Chemistry Aerosol Radiation and Transport model (GOCART). Compared to WRF-Chem and the GOCART aerosol modules, the major updates in GEFS-Aerosols include the FENGSHA dust scheme implemented and developed by ARL, the Blended Global Biomass Burning Emissions Product (GBBEPx V3) from NESDIS, which provides biomass burning emission and Fire Radiative Power (FRP) data with the biomass burning plume rise modules from WRF-Chem, the global anthropogenic emission inventories derived from the Community Emissions Data System (CEDS). Sub-grid scale tracer transport and deposition are handled inside the physics routines, including consistent implementation of positive definite tracer transport and wet scavenging in the Simplified Arakawa-Schubert (SAS) scheme. This study describes the details of GEFS-Aerosols model development and corresponding evaluation of the real-time and retrospective experiments using various observations from in situ measurement, satellite and aircraft data. GEFS-Aerosols have the capability to forecast the aerosols and the hazardous air quality caused by fire and dust events. The predictions demonstrate a substantial improvement for both composition and variability of aerosol distributions over those from the currently operational NGAC global aerosol prediction system.