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RIKEN Center for Computational Science Data Assimilation Research Team

Team Leader: Takemasa Miyoshi (Ph.D.)

Research Summary

Takemasa  Miyoshi(Ph.D.)

Data assimilation (DA) is a cross-disciplinary science to synergize computer simulations and real-world data, using statistical methods and applied mathematics. As computers become more powerful and enable more precise simulations, it will become more important to compare the simulations with actual observations. DA Team performs cutting-edge research and development on advanced DA methods and their wide applications, aiming to integrate computer simulations and real-world data in the wisest way. Particularly, DA Team tackles challenging problems of developing efficient and accurate DA systems for “big simulations” with real-world “big data” from various sources including advanced sensors. The specific foci include 1) theoretical and algorithmic developments for efficient and accurate DA, 2) DA methods and applications by taking advantage of the world-leading supercomputer and “big data” from new advanced sensors, and 3) exploratory new applications of DA in wider simulation fields. These advanced DA studies will enhance simulation capabilities and lead to a better use of high-performance computers.

Main Research Fields

  • Mathematical & Physical Sciences

Related Research Fields

  • Informatics


  • Data Assimilation
  • Numerical Weather Prediction
  • Large Scale Simulation
  • Ensemble Data Assimilation
  • Natural disaster prediction

Research Subjects

  • Ensemble-based data assimilation suitable to various high-dimensional simulations
  • Theoretical research on challenging problems in data assimilation
  • Wide applications of data assimilation
  • Cutting-edge data assimilation research on geophysical applications
  • Data assimilation using Big Data

Selected Publications

  • 1. H. Yashiro, K. Terasaki, Y. Kawai, S. Kudo, T. Miyoshi, T. Imamura, K. Minami, H. Inoue, T. Nishiki, T. Saji, M. Satoh, and H. Tomita
    "A 1024-Member Ensemble Data Assimilation with 3.5-Km Mesh Global Weather Simulations"
    in SC20: International Conference for High Performance Computing, Networking, Storage and Analysis (SC), Atlanta, GA, US, pp. 1-10. (2020).
  • 2. Kotsuki, S., Pensoneault, A., Okazaki, A. and Miyoshi, T.
    "Weight Structure of the Local Ensemble Transform Kalman Filter: A Case with an Intermediate AGCM."
    Q. J. R. Meteorol. Soc., 146, Issue732, 3399-3415. (2020).
  • 3. Otsuka, S., S. Kotsuki, M. Ohhigashi, and T. Miyoshi
    "GSMaP RIKEN Nowcast: Global precipitation nowcasting with data assimilation"
    J. Meteor. Soc. Japan, 97, 1099-1117. (2019).
  • 4. Honda, T., S. Kotsuki, G.-Y. Lien, Y. Maejima, K. Okamoto and T. Miyoshi
    "Assimilation of Himawari-8 All-Sky Radiances Every 10 Minutes: Impact on Precipitation and Flood Risk Prediction"
    J. Geophys. Res., 123, 965-976 (2018).
  • 5. Kotsuki, S., T. Miyoshi, K. Terasaki, G.-Y. Lien and E. Kalnay
    "Assimilating the Global Satellite Mapping of Precipitation Data with the Nonhydrostatic Icosahedral Atmospheric Model NICAM"
    J. Geophys. Res., 122, 631-650 (2017).
  • 6. Arakida, H., T. Miyoshi, T. Ise, S. Shima and S. Kotsuki
    "Non-Gaussian data assimilation of satellite-based Leaf Area Index observations with an individual-based dynamic global vegetation model"
    Nonlinear Processes in Geophys., 24, 553-567 (2017).
  • 7. Miyoshi, T., G.-Y. Lien, S. Satoh, T. Ushio, K. Bessho, H. Tomita, S. Nishizawa, R. Yoshida, S. A. Adachi, J. Liao, B. Gerofi, Y. Ishikawa, M. Kunii, J. Ruiz, Y. Maejima, S. Otsuka, M. Otsuka, K. Okamoto, and H. Seko
    ""Big Data Assimilation" toward Post-peta-scale Severe Weather Prediction: An Overview and Progress"
    Proc. of the IEEE, 104, 2155-2179 (2016).
  • 8. Miyoshi, T., M. Kunii, J. Ruiz, G.-Y. Lien, S. Satoh, T. Ushio, K. Bessho, H. Seko, H. Tomita, and Y. Ishikawa
    ""Big Data Assimilation" Revolutionizing Severe Weather Prediction"
    Bull. Amer. Meteor. Soc., 97, 1347-1354 (2016).
  • 9. Miyoshi, T., K. Kondo, and K. Terasaki
    "Big Ensemble Data Assimilation in Numerical Weather Prediction"
    Computer, 48, 15-21 (2015).
  • 10. Miyoshi, T., K. Kondo, and T. Imamura
    "The 10240-member ensemble Kalman filtering with an intermediate AGCM"
    Geophys. Res. Lett., 41, 5264-5271 (2014).

Recent Research Results

Related Links

Lab Members

Principal investigator

Takemasa Miyoshi
Team Leader

Core members

Shigenori Otsuka
Research Scientist
James Taylor
Research Scientist
Michael Robert Goodliff
Research Scientist
Arata Amemiya
Postdoctoral Researcher
Shun Ohishi
Postdoctoral Researcher
Yasumitsu Maejima
Postdoctoral Researcher
Jianyu Liang
Postdoctoral Researcher
Rakesh Teja Konduru
Postdoctoral Researcher
Kota Takeda
Junior Research Associate
Hideyuki Sakamoto
Technical Staff I
Takahisa Ishimizu
Technical Staff I
Shu-Chih Yang
Senior Visiting Scientist
Juan Ruiz
Visiting Scientist
Atsushi Okazaki
Visiting Scientist
Shunji Kotsuki
Visiting Scientist
Tobias Marcel Necker
Visiting Scientist


Position Deadline
Seeking a few Senior Scientists, Research Scientists or Postdoctoral Researchers (R-CCS2121) Open until filled

Contact Information

Email: da-team-desk [at] ml.riken.jp