In line with a comprehensive revision and review of the Manual on the Global Data-processing and Forecasting System (GDPFS) (WMO-No.485), the Japan Meteorological Agency (JMA) was designated as a Regional Specialized Meteorological Centre (RSMC) for general-purpose activities in global deterministic and ensemble numerical weather prediction. Accordingly, the Agency will begin providing global deterministic and ensemble forecast datasets via the GISC Tokyo server on May 21st 2019.
Table 1 below shows the directories and file names of the related global forecasting data. File names are based on the Manual on the Global Telecommunication System (WMO-No. 386) with GRIB2 formatted data. The values of yyyy, mm, dd and hh represent the year, month, date and hour of the forecast initial time. The initial times for deterministic 132-hour forecasts are 00, 06, 12 and 18 UTC. Such forecasts up to 264 hours are available only at 12 UTC, and the initial times for ensemble forecasts are 00 and 12 UTC.
| Deterministic / Ensemble (grid interval) | Forecast Time (Time Interval) | Directory under main* | File Name |
| Deterministic (1.25 deg.) | 0–132 hours (6 hourly) | Global_Spectral_Model/Latitude_Longitude/1.25_1.25/90.0_-90.0_0.0_358.75/Upper_air_layers/[yyyymmdd]/[hh0000]/ | W_jp-JMA-tokyo,MODEL,JMA+gsm+gpv,C_RJTD_[yyyymmddhh0000]_GSM_GPV_Rgl_Gll1p25deg_L-all_FD0000-0512_grib2.bin |
| 144–264 hours (12 hourly) | W_jp-JMA-tokyo,MODEL,JMA+gsm+gpv,C_RJTD_[yyyymmddhh0000]_GSM_GPV_Rgl_Gll1p25deg_L-all_FD0600-1100_grib2.bin | ||
| Ensemble (1.25 deg.) | 0–264 hours (12 hourly) | One-week_Ensemble_Prediction_System/Latitude_Longitude/1.25_1.25/90.0_-90.0_0.0_358.75/Upper_air_layers/[yyyymmdd]/[hh0000]/ | W_jp-JMA-tokyo,MODEL,JMA+epsg+gpv,C_RJTD_[yyyymmddhh0000]_EPSG_GPV_Rgl_Gll1p25deg_L-all_FD0000-1100_Eem_grib2.bin |
The parameters of deterministic forecasts up to 132 and 264 hours are identical (Table 2). Table 3 shows the parameters of global ensemble forecasts (ensemble means, spreads, and probabilities as specified in Appendix 2.2.5 of the Manual on GDPFS (WMO-No. 485)). The data domain for global deterministic and ensemble forecast data is worldwide in latitude and longitude projection.
| Parameter | Levels (hPa) |
| Geopotential height | 1000, 925, 850, 700, 600, 500, 400, 300, 250, 200, 150, 100, 70, 50, 30, 20, 10 |
| Temperature | |
| Zonal (u) and meridional (v) wind speed | |
| Relative Humidity | 1000, 925, 850, 700, 600, 500, 400, 300 |
| Vertical pressure velocity | 1000, 925, 850, 700, 600, 500, 400, 300 |
| Vorticity | 925, 700, 500, 250 |
| Divergence | 925, 700, 250 |
| Velocity potential, and stream function | 850, 200 |
| Mean Sea Level Pressure, 2 m temperature, relative humidity, 10 m wind (u, v), and total precipitation | Surface |
| Parameter | Threshold | |
| Precipitation | Probability | 1, 5, 10, 25, 50, 100 mm/24 hours |
| 10 m sustained wind, and gusts | 10, 15, 25 m/s | |
| Temperature anomalies at 850 hPa | ±1, ±1.5, ±2 standard deviation with respect to a reanalysis climatology | |
| Geopotential height at 1000 and 500 hPa | Ensemble mean, and spread (standard deviation) | N / A |
| Mean sea level pressure | ||
| Wind speed at 850 and 250 hPa | ||
| Zonal wind speed at 850 and 250 hPa | ||
| Meridional wind speed at 850 and 250 hPa | ||
| Temperature at 850 hPa | ||