[A-AS12] [EE] 高性能スーパーコンピュータを用いた最新の大気科学

[AAS12-12] ポスト京コンピュータにおける超高解像度全球データ同化への挑戦：データスループット性能に着目したアンサンブル同化システムの開発

★招待講演

*八代 尚¹、寺崎 康児¹、三好 建正¹、冨田 浩文¹ (1.国立研究開発法人理化学研究所　計算科学研究機構)

キーワード：High Performance Computing (HPC), data assimilation, global cloud resolving simulation

The weather/climate simulation models and the data assimilation (DA) systems are placed as the important applications in the development of post-K supercomputer system. In a cyclic operation of the DA system, the simulation model and the DA system are executed cooperatively. In recent years, the horizontal resolution of the simulation model increases, and the ensemble size increases, too. In such situation, data movement between the two applications becomes a more significant issue.
We proposed an ensemble DA framework with a "throughput-aware” design that maintains data locality and maximizes the throughput of file I/O between the simulation model and the ensemble DA system. This framework is implemented to a DA system, which is used a local ensemble transform Kalman filter (LETKF) and a Non-hydrostatic Icosahedral Atmospheric Model (NICAM) (NICAM-LETKF, Terasaki et al., 2015). The results of benchmark test on the K computer showed a reduction in a total executed time and a better scalability up to 10,000 nodes in comparison with the current system. Our new concept is effective for the speedup of the workflow and enables to expand the computational scale of the DA system.