HRRR Composite Reflectivity image

Assimilation and Verification Innovation Division

Making Forecasts Better

The Assimilation Development Branch works on techniques to assimilate all types of weather observations, including radar and satellite data, into weather prediction models. These assimilation techniques are applied to regional models, but some applications are moving towards global model data assimilation.

The Assimilation Development Branch (ADB) is divided into two sections:

The Assimilation Section develops advanced observational data assimilation techniques, including radar and satellite data but also for all observational data. These assimilation techniques are applied in particular for regional models but with some applications working towards global model data assimilation.

The Model Assessment Section develops integrated, common verification applications for model and assimilation research and development, and for observation sensitivity experiments.

Forecast Models



    FIM Image - Precipitable Water

    GSL's FIM (Flow-Following Finite-Volume Icosahedral Model) uses a unique hexagonal mesh grid to improve modeling of weather systems at all latitudes from very short-range to week 3-4. GSL also has experience on development of non-hydrostatic global models and is involved in initial planning and development toward NOAA's Next-Generation Global Prediction System (NGGPS).


  • HRRR (3km)

    HRRR Composite Reflectivity

    The High-Resolution Rapid Refresh (HRRR) is the only hourly updating model that can predict individual thunderstorms on a 3km grid over the U.S.

  • RAP (13km)

    RAP Surface Temperature image

    The Rapid Refresh (RAP) is NOAA’s North American hourly-updating model system that ingests data from a network of ground and satellite-based sensors, radar, and aircraft.


  • WRF-Chem

    WRF-Chem Image

    GSL leads the development of WRF-Chem (Weather Research and Forecasting - Chemistry), a next-generation coupled weather and air quality prediction system based on the existing Weather Research and Forecast Model.

  • Nowcasting

    LAPS All-sky Image

    EMB scientists are focused on the application of Gridpoint Statistical Interpolation (GSI) to nowcasting applications including RTMA (Real-Time Mesoscale Analysis) and its 3-d counterpart, the Rapidly Updated Analysis (RUA).