Recent Development of LETKF on JMA GSM

Yoichiro Ota
JMA Visiting Scientist


The Numerical Prediction Division of Japan Meteorological Agency (JMA-NPD) has been operating a global ensemble prediction system (EPS) for the medium-range forecast up to nine days. Forecast model is a low resolution version of the Global Spectral Model (GSM). Initial perturbations are generated by Singular Vector (SV) method and the initial condition of unperturbed run is the spectrally truncated fields from the global deterministic analysis. The overview of the numerical weather prediction system in JMA and the recent developments will be addressed in addition to the future implementation plans.

JMA is now developing Local Ensemble Transform Kalman Filters (LETKF) as the next generation global EPS. In LETKF system, the forecast model and the quality control of observations are same as the operational system. Direct comparison of forecast skills between LETKF and the operational system (both deterministic and ensemble forecast) will be presented. Also, recent developments on the LETKF system will be shown.