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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, based on statistical mathematics and dynamical systems theory. As computer technology advances and enables precise simulations, it will become more important to compare simulations with real-world data.

We are researching and developing advanced DA methods and their various applications, and we aim to integrate computer simulations and real-world data in the most effective way. Particularly, we tackle the challenging problems involved in developing efficient and accurate DA systems for “big simulations” with real-world big data from various sources including advanced sensors. Our specific foci include 1) theoretical and algorithmic developments for efficient and accurate DA; 2) development of DA methods and applications by taking advantage of the world-leading K computer and big data derived from advanced new sensors; and 3) the exploration of new DA applications in wider simulation fields. These advanced DA studies will enhance simulation capabilities and lead to 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.Kotsuki, S., K. Kurosawa, and T. Miyoshi.:
    "On the Properties of Ensemble Forecast Sensitivity to Observations"
    Quart. J. Roy. Meteorol. Soc., in press. doi:10.1002/qj.3534 (2019).
  • 2.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).
  • 3.Honda, T., T. Miyoshi, G.-Y. Lien, S. Nishizawa, R. Yoshida, S. A. Adachi, K. Terasaki, K. Okamoto, H. Tomita and K. Bessho.:
    "Assimilating All-Sky Himawari-8 Satellite Infrared Radiances: A Case of Typhoon Soudelor (2015)"
    Mon. Wea. Rev., 146, 213-229 (2018).
  • 4.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).
  • 5.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).
  • 6.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).
  • 7.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).
  • 8.Otsuka, S., S. Kotsuki, and T. Miyoshi:
    "Nowcasting with data assimilation: a case of Global Satellite Mapping of Precipitation"
    Weather and Forecasting, 31, 1409-1416 (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).

Related Links

Lab Members

Principal investigator

Takemasa Miyoshi
Team Leader

Core members

Koji Terasaki
Research Scientist
Shigenori Otsuka
Research Scientist
Shunji Kotsuki
Research Scientist
Takumi Honda
Postdoctoral Researcher
Kohei Takatama
Postdoctoral Researcher
James Taylor
Postdoctoral Researcher
Arata Amemiya
Postdoctoral Researcher
Hironori Arai
Postdoctoral Researcher
Yasumitsu Maejima
Research Associate
Hazuki Arakida
Technical Staff I
Hideyuki Sakamoto
Technical Staff I
Marimo Ohhigashi
Technical Staff I
Kenta Kurosawa
Technical Staff I
John Craig Wells
Senior Visiting Scientist
Juan Ruiz
Visiting Scientist
Shu-Chih Yang
Visiting Scientist
Stephen Penny
Visiting Scientist
Yohei Sawada
Visiting Scientist
Shohei Takino
Visiting Scientist
Pierre Francois Yves Tandeo
Visiting Scientist
Keiichi Kondo
Visiting Scientist
Atsushi Okazaki
Visiting Scientist


Position Deadline
Seeking a Research Scientist or Senior Research Scientist (20K15) April 23, 2020
Seeking Senior Scientist/Research Scientist/Postdoctoral Researcher Open until filled

Contact Information

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