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. NGGPS FV3-based Unified Modeling System will be a community guided system.

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

 

Summary Documentation

Dynamical Core Phase 2 Test Report

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

Phase 1 testing built upon the High Impact Weather Predication Project (HIWPP) and evaluated six potential candidate dynamical cores:

• Non-hydrostatic Global Spectral Model (GSM)-EMC1
• Global Non-hydrostatic Mesoscale Model (NMM & NMM-UJ) - EMC
• Model for Prediction Across Scales (MPAS) - NCAR
• Non-hydrostatic Icosohedral Model (NIM) - ESRL
• Navy Environmental Prediction System Using the NUMA Core (NEPTUNE) - Navy
• Finite Volume Model version3 - (FV3) - GFDL

1The Non-hydrostatic GSM was an initial candidate in Phase 1 but did not participate in tests.

The DTG's assessment of the tests and results in Phase 1 resulted in the recommendation to reduce the candidate pool to two cores. Assessment of the test results of Phase 1 determined that going forward to Phase 2 with two dynamical cores is a low technical risk, and that no unique dynamical core quality will be lost. The conclusion of Phase 1 testing is the decision to proceed to Phase 2 testing on schedule with two dynamical cores. 

Summary Documentation

Executive Summary Report (pdf)

Idealized Tests leveraging High Impact Weather Prediction Project (HIWPP)

3-km Three Day Simulations leveraging High Impact Weather Prediction Project (HIWPP)

Benchmarking performance and scalability report by the Advanced Computing Evaluation Committee (AVEC)

Addendum to Benchmarking performance and scalability report by the Advanced Computing Evaluation Committee (AVEC)