J55.3 Computational Resources Optimization in the NCEP Coupled Atmospheric Wave–Chemistry Global Ensemble Forecast System

Wednesday, 15 January 2020: 3:30 PM
212 (Boston Convention and Exhibition Center)
Dingchen Hou, NOAA/NWS/NCEP/EMC, College Park, MD; and X. Xue, W. Kolczynski Jr., B. Fu, Y. Zhu, J. H. Alves, J. Meixner, L. Pan, and J. Kain

The Global Ensemble Forecast System (GEFS) is an important component of the NCEP production suite and it is drawing more and more attention from the users and research community. Its coming upgrade, v12, will be the first ensemble forecast system using NCEP's latest global numerical weather prediction model with the FV3 dynamic core. In addition, for the first time the atmospheric model will be coupled with a wave model (Wave Watch 3) and the GSD Chemistry model.

Development and implementation of GEFS v12 faces numerous challenges and one of the most striking is the operational computational resources. The model forecast job needs to be fitted into a 1-hour time window of the NCEP operational supercomputer, using a limited number of computational nodes. The FV3 atmospheric model has been recently adopted to the NCEP production suite and its unique spherical grid structure, including 6 cubic tiles, introduces a new challenge in task configuration and scalability. The coupling mechanism provided by the Earth System Modeling Framework (ESMF) with wave and chemistry models faces its first test in NCEP production environment. In addition, to support general development and especially reforecasts and retrospective forecasts, solid resource scalability must be provided to allow the model to run smoothly with reduced number of nodes and a longer time window.

This presentation will cover the work conducted to tackle these challenges and will share our experiences with the community. Extensive experiments with the FV3 (stand alone) model have led to substantial increases in computational efficiency and commensurate reduction in the number of nodes required for integration. For that scenario, the operational configuration and scaling options for development has been confidently decided. Similar effort is in progress for the ESMF coupling capabilities and the experience for the wave and chemistry models will be incorporated into the coupled GEFS v12. Coordination of all these components will be carried out and we will describe the candidate settings for the final computation resource of the implementation.

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