The Next Generation Global Prediction System (NGGPS) Dynamic Core Test Group (DTG): Organization and Process

As part of its Research to Operations (R2O) Initiative, the National Weather Service (NWS) plans to develop and implement a state-of-the-art Next Generation Global Prediction system (NGGPS) which will be readily adaptable to and scalable on evolving High-Performance Computing (HPC) architectures. The NGGPS will be designed to produce useful forecast guidance to 30 days, as well as become the foundation for the operating forecast guidance system (Global Forecast System) for the next several decades.

The current operational Global Forecast System is based on the Global Spectral Model. The Global Forecast System is an operational, very mature hydrostatic dynamic model with known limitations regarding scalability and adaptability to future computing architectures. The future NGGPS will require an atmospheric dynamic core (dycore) that is non-hydrostatic, highly scalable and architecturally compatible with projected high performance computing architecture. Six dycores from a variety of institutions were evaluated as potential candidates for the new system. A NGGPS Dycore Testing Plan was developed to guide the testing of these dycores and leverage ongoing High-Impact Weather Prediction Project (HIWPP) activities in the evaluation of the dycores.

Objective and unbiased assessment of the test and evaluation results was essential to the selection of the future atmospheric model dycore for the NGGPS. A Dynamic core Test Group (DTG) was therefore established to conduct this assessment. The DTG evaluated the test plan, formulated and approved test criteria, guided the conduct of the test, and assessed test results. This assessment, along with business considerations was used in the development of the business case supporting the selection of the next dycore by NWS management.

The role of the DTG was to review the technical aspects of all dycore testing and provide an assessment of test results to NWS management for each of the candidate dycores. The DTG provided guidance on outstanding issues relayed from the Advanced Computing Evaluation Committee (AVEC) and the NGGPS Project Management Team regarding the preparation for and conduct of dycore performance testing and advised on resolution of conflicts on testing procedures.

Membership of the DTG included representation from candidate dycore organizations, NWS Office of Science and Technology Integration leadership, NGGPS program management, testing managers, and subject matter expert consultants. DTG membership was chosen to allow for broad, but bounded, input and application of ideas and expertise in group proceedings.