1. Forecast system version
Identifier code:
First operational forecast run:
2. Configuration of the forecast model
Is the model coupled to an ocean model?
Coupling frequency:
2.1 Atmosphere and land surface
| Model | |
|---|---|
| Horizontal resolution and grid | |
| Atmosphere vertical resolution | |
| Top of atmosphere | |
| Soil levels | |
| Time step |
Detailed documentation:
2.1 Ocean and cryosphere
| Ocean model | NEMO v3.4 |
|---|---|
| Horizontal resolution | ORCA 0.25 |
| Vertical resolution | L75 |
| Time step | |
| Sea ice model | |
| Sea ice model resolution | |
| Sea ice model levels | |
| Wave model | |
| Wave model resolution | 0.5 degrees |
Detailed documentation: NEMO documentation
3. Initialization and initial condition (IC) perturbations
3.1 Atmosphere and land
| Re-forecast | Forecast | |
|---|---|---|
| Atmosphere initialization | ERA-Interim | |
| Atmosphere IC perturbations | ||
Land Initialization | ||
| Land IC perturbations | ||
| Soil moisture initialization | ||
| Snow initialization | ||
| Unperturbed control forecast? |
Detailed documentation: IFS cycle 43r1 documentation and SEAS5 user guide
More DA details?
Data assimilation method for control analysis: 4D Var (atmosphere) and 3DVAR (ocean/sea-ice)
Horizontal and vertical resolution of perturbations: T42L91 SVs+ T399L137 EDA perturbations
Perturbations in +/- pairs: Yes
3.2 Ocean and cryosphere
| Re-forecast | Forecast | |
|---|---|---|
| Ocean initialization | ORAS5 | ORTA5 |
| Ocean IC perturbations | Yes - generated through perturbations to assimilated observations and surface forcing | Yes - generated through perturbations to assimilated observations and surface forcing |
| Unperturbed control forecast? | No | No |
Detailed documentation: ECMWF ocean reanalysis documentation and SEAS5 user guide
Ocean data assimilation details? Source and treatment of SST? (Other data sources - altimetry?)
4. Model Uncertainties perturbations:
| Model dynamics perturbations | No |
|---|---|
| Model physics perturbations | 3-lev SPPT and SPBS |
If there is a control forecast, is it perturbed? | Yes |
Detailed documentation: IFS cycle 43r1 documentation
5. Forecast system and re-forecasts
Note, the ECMWF seasonal forecasts cover two time ranges: the long range (LR) forecasts out to 7 months, and annual range (AR) forecasts out to 13 months. The model used for these forecasts is identical, but they have different numbers of forecast members.
| Forecast frequency | monthly (LR) quarterly (AR) |
|---|---|
| Forecast ensemble size | 51 (LR) 15 (AR) |
| Re-forecast years | 36 (1981-2016) |
| Re-forecast ensemble size | 25 (LR) 15 (AR) |
| On-the-fly or static re-forecast set? | static |
| Calibration (bias correction) period | 1993-2016 |
6. Where to find more information
ECMWF seasonal forecast documentation page
