JMA system

11 December 2019

    • All-sky assimilation of microwave imager (AMSR2/GCOM-W, GMI/GPM, SSMIS/DMSP F-17, F-18, WindSat/Coriolis, MWRI/FY-3C) and microwave water-vapor sounder (GMI/GPM, MHS/NOAA-19, Metop-A, -B) was started.
    • Assimilation of ASCAT from Metop-C was started.
    • Hybrid background error covariances estimated with LETKF and outer-loop iteration were introduced in 4D-Var system.

9 May 2019

A new report on the outline of the latest operational numerical weather prediction (NWP) system at the Japan Meteorological Agency (JMA) has been published. The  report presents technical details of the operational NWP systems of JMA as of June 2018, as an appendix to WMO Technical Progress Report on the Global Data-processing and Forecasting System (GDPFS) and Numerical Weather Prediction (NWP) Research.

JMA is working forward a further developments to improve the accuracy of NWP models. You will find updated information on the NWP systems of JMA on the JMA’s websites:
— and

5 March 2019:

      • The assimilation of the ATMS (Advanced Technology Microwave Sounder) and CrIS (Cross-track Infrared Sounder) data from NOAA-20 into the JMA’s Global NWP system was started at 00UTC on 5 March 2019.  The data was also started to be assimilated into the JMA’s Global EPS by the Local Ensemble Transform Kalman Filter (LETKF) to generate initial perturbations.
      • The initial perturbations made by LETKF in the JMA’s Global EPS was upgraded at 00UTC on 5 March 2019 as follows:
        — using the 6 hour forecast perturbations from the previous LETKF analysis ensemble
        — tuning of the horizontal and vertical localization functions in the LETKF.

18 October 2018:

JMA enhanced the usage of the clear-sky radiance (CSR) data from geostationary satellites (i.e. Himawari-8, Meteosat-8, 11 and GOES-15) in JMA’s global NWP system at 00 UTC on 18 October 2018.  In detail, there were two major updates:
(1) JMA began assimilating surface-sensitive CSR data from Himawari-8 Band 9 and 10 and Meteosat-8, 11 Channel 6.
(2) JMA began assimilating hourly CSR data from Meteosat-8, 11 and GOES-15 by stopping thinning data every two hours. (Note: Hourly CSR data from Himawari-8 have been already used since March 2016.)
The amount of CSR data assimilated into the JMA’s global NWP system became about double by these updates.

5 June 2018: 

JMA began the operation of a new supercomputer system.         See  for details