Global Ensemble Forecast System (GEFS) – Aerosol Model

The National Oceanic and Atmospheric Administration (NOAA)’s National Weather Service (NWS) is on its way to deploying various operational prediction applications using the Unified Forecast System (UFS), a community-based coupled, comprehensive Earth modeling system. An aerosol model component developed in collaboration between the Global Systems Laboratory, Chemical Science Laboratory, Air Resources Laboratory, and Environmental Modeling Center (GSL, CSL, ARL, EMC) 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 framework. This aerosol prediction system replaced the NEMS GFS Aerosol Component version 2 (NGACv2) system in the National Center for Environment Prediction (NCEP) production suite in September 2020 as one of the ensemble members of the Global Ensemble Forecast System (GEFS), dubbed GEFS-Aerosols v1. The aerosol component of atmospheric composition in the GEFS is based on the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem). GEFS-Aerosols includes bulk modules from the Goddard Chemistry Aerosol Radiation and Transport model (GOCART). GEFS-Aerosols predicts aerosol sources from anthropogenic and natural sources from dust, fires and seasalt and includes sulfate, black carbon, organic carbon, dust and seasalt.

Differences of GEFS-Aerosols and NGACv2 Day-1 predictions of total AOD compared to MERRA-2 reanalysis averaged during 5 July–30 November 2019. Image credit: Zhang,

Diagram of the GEFS-Aerosol coupled structure.

Reference: Zhang, L., Montuoro, R., McKeen, S. A., Baker, B., Bhattacharjee, P. S., Grell, G. A., Henderson, J., Pan, L., Frost, G. J., McQueen, J., Saylor, R., Li, H., Ahmadov, R., Wang, J., Stajner, I., Kondragunta, S., Zhang, X., and Li, F.: Development and evaluation of the Aerosol Forecast Member in the National Center for Environment Prediction (NCEP)’s Global Ensemble Forecast System (GEFS-Aerosols v1), Geosci. Model Dev., 15, 5337–5369,, 2022.