Detailed model description
Page containing details for all model configurations available in S2S since the project start => JMA model description
Overview of the model changes
| Model version | Implement. date in S2S | Time range | Resolution | Ens. Size | Frequency | Re-forecasts | Rfc period | Rfc frequency | Rfc size | Ocean resolution | Active Sea Ice | Remarks |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
CPS3 | 19/02/2023 | d 0-34 | Tl319L100 | 4+1 | daily | fixed | 1991-2020 (model version date 30/09/2022) | 2/month (*3) | 4+1 | 0.25° L60 | yes | |
GEPS2203 | 15/03/2022 | d 0-34 | Tq479/Tq319L128 | 49+1 | weekly (Wed) lagged eps created from 2 runs (*5) | fixed | 1991-2020 (model version date 31/03/2022) | 2/month (always on the 15th and the last day of month *3) | 12+1 | N/A | N/A | |
GEPS2103 | 30/03/2021 | d 0-34 | Tl479/Tl319L128 | 49+1 | weekly (Wed) lagged eps created from 2 runs (*5) | fixed | 1981-2020 (model version date 31/03/2021) | 2/month (always on the 15th and the last day of month *3) | 12+1 | N/A | N/A | |
GEPS2003 | 24/03/2020 | d 0-34 | Tl479/Tl319L100 | 49+1 | weekly (Wed) lagged eps created from 4 runs (*4) | fixed | 1981-2010 (model version date 31/03/2020) | 2/month (always on the 15th and the last day of month *3) | 12+1 | N/A | N/A | |
GEPS1701 | 22/03/2017 | d 0-34 | Tl479/Tl319L100 | 49+1 | weekly (Wed) lagged eps created from 4 runs (*4) | fixed | 1981-2012 (model version date 31/01/2017) | 3/month (always on the 10th, 20th and the last day of month *3) | 4+1 | N/A | N/A | |
GSM1403C | 06/01/2015 | d 0-34 | Tl319/L60 | 24+1 | 2/week (Tue, Wed) | fixed | 1981-2010 (model version date 04/03/2014) | 3/month (always on the 10th, 20th and the last day of month *3) | 4+1 | N/A | N/A |
- (*3) For exact list of JMA reforecast dates for each model version date refer to https://apps.ecmwf.int/datasets/data/s2s-reforecasts-instantaneous-accum-rjtd/levtype=sfc/type=cf/
Description of the main changes
CPS3
- General changes:
- model changed from GEPS to CPS coupled to an ocean model
- output frequency for 10 metre wind and precipitation changed from 24 hour to 6 hour
- increased number of vertical layers for vertical velocity
- Surface thermal radiation downwards parameter newly provided
- Real-time forecasts changes:
- ensemble size decreased from 25 to 5
- frequency changed from twice a week (every Tuesday and Wednesday at 12Z) to every day (00Z)
- total data size increased from 6.6 GB to 8.4 GB per week, but decreased from 3.3 GB to 1.2 GB per day due to change the ensemble size and a forecast frequency
- Re-forecasts changes:
- ensemble size decreased from 13 to 5
- total data size for the re-forecast: ~1TB
- frequency (twice a month) and period (1991-2020) don't change, but start dates for each re-forecast year changed to:
Jan: 16 and 31
Feb: 10 and 25
Mar: 12 and 27
Apr: 11 and 26
May: 16 and 31
Jun: 15 and 30
Jul: 15 and 30
Aug: 14 and 29
Sep: 13 and 28
Oct: 13 and 28
Nov: 12 and 27
Dec: 12 and 27
GEPS2203
- The horizontal resolution improved to about 40km up to 18 days and about 55km after that. The physical parameterization schemes and two-tiread SST method are improved.
- operational from
GEPS2103
- The new JMA real-time ensemble system includes 2 start dates (Tuesdays and Wednesdays at 12Z) instead of the previous 4 runs (see the description in GEPS1701 below). The ensemble size is 25 members for both days and the resulting new lagged ensemble for S2S is a single 50-member ensemble starting on Wednesdays at 12Z.
- operational from
GEPS2003
two-tiered Sea Surface Temperature (SST) method is implemented in addition to improved physical parameterization schemes in the forecast model. In this approach, the oceanic lower-boundary condition is relaxed from the anomaly-fixed SST to the ensemble-mean SST based on prediction using the Seasonal Ensemble Prediction System (Seasonal EPS).
There is no change in the number of fields for real-time data but the number of reforecast ensemble members is increased from 5 to 13, and the number of frequency is reduced from 3 to 2 per month.
- operational from
GEPS1701
- The new JMA real-time ensemble system includes 4 start dates (Tuesdays at 00Z and 12Z + Wednesdays at 00Z + 12Z) instead of the previous 2 only (25-member ensembles starting on Tuesday 12Z and Wednesday 12 Z). The ensemble size is 13 members for Tuesdays 12Z and Wednesdays 00 and 12Z and 11 members for Tuesdays 00Z. Because the usage of such data would be very difficult for users, a lagged ensemble is being created for S2S archive instead. The resulting new lagged ensemble is a single 50-member ensemble starting on Wednesdays at 12Z
- operational from