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1. Forecast system version
System name: GloSea5-GC2
First operational forecast run: 3 February 2015
2. Configuration of the forecast model
Is it a coupled model ? Yes: Atmosphere, land, ocean and sea-ice.
Coupling frequency: 3-hourly coupling between atmosphere-land and ocean--sea-ice.
(Better use more specific question? Here or elsewhere?)
The coupled model Global Coupled 2 (GC2) is described in Williams et al, 2015.
2.1 Atmosphere and land surface
| Model | Met Office Unified Model (UM) - Global Atmosphere 6.0 Joint UK Land Environment Simulator (JULES) - Global Land 6.0 |
|---|---|
| Horizontal resolution and grid | N216: 0.83 degrees x 0.56 degrees (approx 60km in mid-latitudes) |
| Atmosphere vertical resolution | 85 levels |
| Top of atmosphere | 85km |
| Soil levels | 4 Level 1 : 0 - 0.1 m Level 2 : 0.1 - 0.35 Level 3 : 0.35 - 1.0 m Level 4 : 1.0 - 3.0 m |
| Time step | 15 minutes |
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Global Atmosphere 6.0 & Global Land 6.0: Walters et al, 2017
More model details? (e.g. land surface model?)
2.
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2 Ocean and cryosphere
| Ocean model | NEMO v3.4 - Global Ocean 5.0 |
|---|---|
| Horizontal resolution | ORCA 0.25 |
| Vertical resolution | L75 |
| Time step | 22.5 minutes |
| Sea ice model | CICE v4.1 - Global Sea-Ice 6.0 |
| Sea ice model resolution | ORCA 0.25 |
| Sea ice model levels | 5 categories + open water |
| Wave model | N/A |
| Wave model resolution | N/A |
...
Global Sea Ice 6.0: Rae et al, 2015.
3. Initialization and initial condition (IC) perturbations
3.1 Atmosphere and land
| Re-forecastHindcast | Forecast | |
|---|---|---|
| Atmosphere initialization | ERA-Interim | Met Office Global Hybrid 4D-VAR |
| Atmosphere IC perturbations | None | None |
Land Initialization | Climatology/ERA-Interim | Climatology/Met Office Global Hybrid 4D-VAR |
| Land IC perturbations | None | None |
| Soil moisture initialization | Climatology | Climatology |
| Snow initialization | ERA-Interim | Met Office Global 4D-VAR |
| Unperturbed control forecast? | No | No |
...
Met Office Global Hybrid 4D-VAR: Clayton et al, 2013
More DA details? CM:
Data assimilation method for control analysis: 4D Var (atmosphere) and 3DVAR (ocean/sea-ice)
Horizontal and vertical resolution of perturbations: N/A
Perturbations in +/- pairs: N/A
3.2 Ocean and cryosphere
| Re-forecastHindcast | Forecast | |
|---|---|---|
| Ocean initialization | GloSea Ocean Sea-Ice Analysis (GS-OSIA) | Forecast Ocean Assimilation Model (FOAM) |
| Ocean IC perturbations | No | No |
| Unperturbed control forecast? | No | No |
...
The common NEMOVAR system is described in Blockley et al, 2014 . Details of the GS-OSIA can be found in MacLachlan et al, 2015 .
More ocean data assimilation details?
Source and treatment of SST? (Other data sources - altimetry?)
4. Model uncertainties perturbations:
| Model dynamics perturbations | None |
|---|---|
| Model physics perturbations | Atmosphere Stochastic stochastic physics scheme. , SKEB2 |
If there is a control forecast, is it perturbed? | No control |
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5. Forecast system and hindcasts
| Forecast frequency | Dailydaily | |
|---|---|---|
| Forecast ensemble size | 2 per day | |
| Hindcast years | 23 (1993-2015) | |
| Hindcast ensemble size | 28 (4 start dates, 7 per start date) | |
| Hindcast start dates | 1, 9, 17, 25 of | Month - 1 & 1 of Month 0each month |
| On-the-fly or static hindcast set? | on-the-fly | |
6. Where to find more information
GloSea5 system:
- MacLachlan, C., Arribas, A., Peterson, K. A., Maidens, A., Fereday, D., Scaife, A. A., Gordon, M., Vellinga, M., Williams, A., Comer, R. E., Camp, J., Xavier, P. and Madec, G. (2015), Global Seasonal forecast system version 5 (GloSea5): a high-resolution seasonal forecast system. Q.J.R. Meteorol. Soc., 141: 1072–1084. doi:10.1002/qj.2396
- Seasonal prediction at the Met Office
- Upgrades to the Met Office Seasonal Forecast System
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- Clayton, A. M., Lorenc, A. C. and Barker, D. M. (2013), Operational implementation of a hybrid ensemble/4D-Var global data assimilation system at the Met Office. Q.J.R. Meteorol. Soc., 139: 1445–1461. doi:10.1002/qj.2054
Blockley, E. W., Martin, M. J., McLaren, A. J., Ryan, A. G., Waters, J., Lea, D. J., Mirouze, I., Peterson, K. A., Sellar, A., and Storkey, D.: Recent development of the Met Office operational ocean forecasting system: an overview and assessment of the new Global FOAM forecasts, Geosci. Model Dev., 7, 2613-2638, https://doi.org/10.5194/gmd-7-2613-2014, 2014.
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