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NGGPS Dynamical Core Evaluation

At the heart of a numerical weather prediction system is the dynamical core, which describes how the air moves and how the atmosphere behaves. The first step in building the Next Generation Global Predication System (NGGPS) is to select the best possible dynamical core to give us the most accurate representation of the atmosphere.

To provide impartial oversight to the process of selecting a new core from five existing US research models, a Dynamical core Test Group (DTG) was formed. The DTG, comprised of federal, academia, selected subject matter experts, and representatives from each candidate dynamical core, will conduct an overall assessment of test criteria and results to provide a recommendation to NWS leadership.

NOAA announces the selection of the dynamical core:

NOAA to develop new global weather model


Dr. Ricky Rood talks about Weather Prediction and NGGPS with WX GEEKS:

The Future of Weather Forecasting


Technical Overview

Phase 3: Implementation - in process

  • GFDL's Finite Volume v3 (FV3) was selected as the dynamical core for the new NGGPS atmospheric model. Phase 3 dynamical core implementation includes incorporating FV3 into NEMS, and developing advanced physics and data assimilation techniques to match or exceed the skill of operational GFS. In addition, NWS is working with federal partners, universities, and the community to create a fully accessible community model.


    Making a Community Model

    NGGPS FV3-based Unified Modeling System will be a community guided system. Additional information can be found on the Community Participation page.  


Phase 2: Continued Dynamical Core Computational Performance Evaluation- Complete

  • Selecting a single dynamical core upon which to build a unified global coupled system, will be achieved through assessing 10 additional criteria described in the table below. As results from Phase 2 testing are generated, they will be made available here.

    # Evaluation Criteria Results1
    1 Relaxing shallow atmosphere approximation (deep atmosphere dynamics) Results
    2 Accurate conservation of mass, tracers, entropy, and energy Results
    3 Robust model solutions under a wide range of realistic atmospheric initial conditions using a common (GFS) physics package Results
    Results (web)
    4 Computational performance with GFS physics Results
    5 Demonstration of variable resolution and/or nesting capabilities, including physically realistic simulations of convection in the high-resolution region Results
    6 Stable, conservative long integrations with realistic climate statistics Results
    7 Code adaptable to NEMS/ESMF Requirements
    8 Detailed dynamical core documentation, including documentation of vertical grid, numerical filters, time-integration scheme and variable resolution and/or nesting capabilities Documentation
    9 Evaluation of performance in cycled data assimilation Results
    10 Implementation Plan (including costs) Results

    1See Dynamical Core Test Plan for description of testing methodology

    FV3 (pdf)

    (Finite Volume on the Cubed Sphere) from the Geophysical Fluid Dynamics Laboratory (GFDL)    


    (Model for Prediction Across Scales) from the National Center for Atmospheric Research (NCAR)

    Summary Documentation


    Dynamical Core Phase 2 Test Report (pdf)

    AVEC Report: NGGPS Phase 2 Benchmarks and Software Evaluation (Criteria #4, 5, 10) (pdf)

Phase 1: Dynamical Core Computational Performance Evaluation - Complete