The Assimilation and Modeling Branch (AMB) is home to much of the research in NOAA/ESRL/GSD on weather model and data assimilation development for both operational forecasting and research applications and for impact studies for new observing systems. AMB contributes significantly to both regional and global model development, and since 2009 also to atmospheric/ocean coupled models. AMB collaborates strongly with NCEP, NCAR, other groups in ESRL (and GSD), and other labs and universities.

Aviation Flight Rules Composite Reflectivity

Rapid Refresh

AMB scientists lead development of the Rapid Refresh (RAP), an hourly updated weather forecast model/assimilation system that replaced the Rapid Update Cycle (RUC) at NCEP as NOAA's hourly updated model on 1 May 2012. RAP version 2, a major upgrade, was implemented at NCEP on 25 Feb 2014. AMB scientists work with colleagues from NCEP, NCAR, and other labs on RAP development. The RAP differs from the previous RUC in that it uses
  • a RAP-unique version of the Weather Research and Forecast (WRF) model, a community mesoscale forecast model with strong contributions to its development from AMB,
  • an RAP-unique version of the Gridpoint Statistical Interpolation (GSI) assimilation system, and
  • a larger domain covering all of North America.

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High-Resolution Rapid Refresh (HRRR)

The HRRR, a 3-km model initialized hourly with the ESRL-experimental version of the radar-enhanced 13-km RAP, provides unique radar-initialized hourly-updated, convection-resolving forecasts, and runs over a CONUS-wide domain.

Icosahedral Model Precipitable Water/500hPa Height

FIM global model - Flow-following Finite-volume Icosahedral Model

AMB scientists lead work with other scientists from NOAA/ESRL toward the development of a new global atmospheric model including the use of the adaptive isentropic-sigma hybrid vertical coordinate successful with the RUC model, accurate finite-volume horizontal grid, and an icosahedral horizontal grid. ESRL collaborates with NCEP/EMC toward application of the FIM model in the NCEP ESMF framework.

WRF Chem

WRF-Chem model

AMB is leading the development of a next-generation coupled weather/air quality numerical prediction system based upon the WRF model, called WRF-Chem. Gas-phase chemistry and aerosol processes are tightly coupled to meteorology within the WRF model structure. Since the model also includes the aerosol direct and indirect effect in addition to sophisticated microphysics packages, WRF-Chem can be used for process studies that are extremely relevant for global change predictions. WRF-Chem has a large international user base and, in addition to studying global change processes, is used to predict weather, dispersion, and air quality. ESRL/GSD currently runs inline chemistry versions for many of its models, including FIM-chem , RR-chem , and HRRR-chem , all with cycling of 3-d aerosol/chemistry variables.


Observation impact studies

AMB has also conducted studies of forecast impact from different observing systems. AMB is currently focused on a multi-year impact study for TAMDAR (Tropospheric Airborne Meteorological Reporting) regional commercial aircraft observations. AMB has previously examined the impact of the NOAA profiler network and the GPS ground-based precipitable water network (developed at NOAA/ESRL/GSD).