日本地球惑星科学連合2021年大会

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[J] ポスター発表

セッション記号 A (大気水圏科学) » A-AS 大気科学・気象学・大気環境

[A-AS07] スーパーコンピュータを用いた気象・気候・環境科学

2021年6月4日(金) 17:15 〜 18:30 Ch.07

コンビーナ:八代 尚(国立研究開発法人国立環境研究所)、川畑 拓矢(気象研究所)、宮川 知己(東京大学 大気海洋研究所)、寺崎 康児(理化学研究所計算科学研究センター)

17:15 〜 18:30

[AAS07-P04] System-Application Co-design for Supercomputer Fugaku and Global Ensemble Weather Data Assimilation

*八代 尚1,2、寺崎 康児2、河合 佑太2、工藤 周平2、三好 建正2、今村 俊幸2、南 一生2、中野 満寿男3、小玉 知央3、佐藤 正樹4、富田 浩文2 (1.国立環境研究所、2.理化学研究所計算科学研究センター、3.海洋研究開発機構、4.東京大学大気海洋研究所)

キーワード:ハイパフォーマンスコンピューティング、データ同化、全球非静力大気モデル、NICAM、LETKF

The supercomputer Fugaku, Japan's new flagship machine, won the 2020's international benchmark rankings in four categories. This system was developed based on a "system-application co-design" aiming for high performance in real-world scientific computing software. The Nonhydrostatic ICosahedral Atmospheric Model (NICAM) and the Local Ensemble Transform Kalman Filter (LETKF) were chosen as the target applications from the weather and climate science domain. We have improved the computational performance of the NICAM-LETKF data assimilation system to achieve x100 faster computation than the K computer.

Weather/climate models are data-intensive applications, which means that we have to conduct the simulation by transferring data. The "data-centric" design is an essential approach for performance improvement, which is applicable not only to our software but also to other models on other supercomputers. We enhanced the use of lesser precision floating-point arithmetic and developed a performance evaluation method to efficiently find the time-consuming part by non-computational operations. Furthermore, we have made improvements to optimize the data transfer between the simulation and the data assimilation.

Based on the co-design results, we realized a global 3.5 km mesh, 1024-member ensemble data assimilation with 131,705 nodes of Fugaku. In this ground-breaking experiment, 1.3 PB of data was transferred from the simulation to the ensemble data assimilation system. And we showed that about four hours are required to complete one assimilation cycle.