Centers & Labs

RIKEN Center for Computational Science

Data Assimilation Research Team

Team Leader: Takemasa Miyoshi (Ph.D.)
Takemasa  Miyoshi(Ph.D.)

Data assimilation is a cross-disciplinary science to synergize numerical simulations and real-world data, based on statistical mathematics and dynamical systems theory. As computers become more powerful and enable more precise simulations, it will become more important to compare the simulation with real-world observations. Data Assimilation Research Team ("DA team") performs cutting-edge research and development on advanced data assimilation methods and their wide applications, aiming to integrate computer simulations and observational data in the wisest way. Particularly, the DA team will tackle challenging problems of developing efficient and accurate data assimilation systems for high-dimensional simulations with “Big Data”

Main Research Field

Mathematical and physical sciences

Related Research Fields


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., 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
  2. Lien, G.-Y., T. Miyoshi, S. Nishizawa, R. Yoshida, H. Yashiro, S. A. Adachi, T. Yamaura, and H. Tomita:
    "The near-real-time SCALE-LETKF system: A case of the September 2015 Kanto-Tohoku heavy rainfall"
    SOLA, 13, 1-6
  3. 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
  4. 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
  5. 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
  6. Miyoshi, T., K. Kondo, and K. Terasaki:
    "Big Ensemble Data Assimilation in Numerical Weather Prediction"
    Computer, 48, 15-21
  7. Miyoshi, T., K. Kondo, and T. Imamura:
    "The 10240-member ensemble Kalman filtering with an intermediate AGCM"
    Geophys. Res. Lett., 41, 5264-5271
  8. *Miyoshi, T.:
    "The Gaussian Approach to Adaptive Covariance Inflation and Its Implementation with the Local Ensemble Transform Kalman Filter"
    Mon. Wea. Rev., 139, 1519-1535
  9. *Miyoshi, T., Y. Sato, and T. Kadowaki:
    "Ensemble Kalman filter and 4D-Var inter-comparison with the Japanese operational global analysis and prediction system"
    Mon. Wea. Rev., 138, 2846-2866
  10. *Miyoshi, T. and S. Yamane:
    "Local ensemble transform Kalman filtering with an AGCM at a T159/L48 resolution"
    Mon. Wea. Rev., 135, 3841-3861

Lab Members

Principal Investigator

Takemasa Miyoshi
Team Leader

Core Members

Koji Terasaki
Research Scientist
Shigenori Otsuka
Research Scientist
Shunji Kotsuki
Research Scientist
Atsushi Okazaki
Special Postdoctoral Researcher
Takumi Honda
Postdoctoral Researcher
Kohei Takatama
Postdoctoral Researcher
James Taylor
Postdoctoral Researcher
Yasumitsu Maejima
Research Associate
Hazuki Arakida
Technical Staff I
Taeka Awazu
Technical Staff I
Hideyuki Sakamoto
Technical Staff I
Marimo Ohhigashi
Technical Staff I
Kenta Kurosawa
Technical Staff I
John Craig Wells
Senior Visiting Scientist
Shinichiro Shima
Visiting Scientist
Juan Ruiz
Visiting Scientist
Shu-Chih Yang
Visiting Scientist
Stephen Penny
Visiting Scientist
Kozo Okamoto
Visiting Scientist
Michiko Otsuka
Visiting Scientist
Yohei Sawada
Visiting Scientist
Shohei Takino
Visiting Scientist
Pierre Francois Yves Tandeo
Visiting Scientist
Hironori Arai
Visiting Scientist
Guo-Yuan Lien
Visiting Scientist