1. Forecast system version

System name: Météo-France System 6

First operational forecast run:  March 2017 (First used in C3S products in November 2018)

2. Configuration of the forecast model

Is it a coupled model?  yes

Coupling frequency:  3 hours

2.1 Atmosphere and land surface

Model

ARPEGE v6.2
(atmosphere)

SURFEX v8.1
(land surface)

Horizontal resolution and gridTL359; 0.5° reduced Gauss grid
Atmosphere vertical resolution91 layers
Top of atmospheretop layer above 0.2 hPa
Soil levels14 layers
Time step7.5 min

Detailed documentation:

ARPEGE http://www.umr-cnrm.fr/IMG/pdf/arp62ca.july2017.pdf

Soil model (SURFEX) http://www.umr-cnrm.fr/surfex//IMG/pdf/surfex_scidoc_v8.1.pdf


2.2 Ocean and cryosphere

Ocean model

NEMO v3.4

Horizontal resolution1° ORCA grid
Vertical resolution75 levels
Time step30 min
Sea ice modelGELATO v6
Sea ice model resolution1° ORCA grid
Sea ice model levels9 (+1 for snow)
Wave modelNone
Wave model resolutionNA

Detailed documentation: NEMO documentation

GELATO documentation 

3. Initialization and initial condition (IC) perturbations

3.1 Atmosphere and land


HindcastForecast
Atmosphere initialization
ERA-interimIFS
Atmosphere IC perturbationsnonenone

Land Initialization

ERA-interimIFS
Land IC perturbationsnonenone
Soil moisture initializationERA-interimIFS
Snow initializationERA-interimIFS
Unperturbed control forecast?NANA

Detailed documentation: see ECMWF page



3.2 Ocean and cryosphere


HindcastForecast
Ocean initializationGLORYS2V2Mercator-Ocean
Ocean IC perturbationsNoneNone
Unperturbed control forecast?NANA

Detailed documentation: http://www.mercator-ocean.fr/science/GLORYS


4. Model uncertainties perturbations:

Model dynamics perturbationsYes
Model physics perturbationsNo

If there is a control forecast, is it perturbed?

NA

Detailed documentation:Batté, L. and Déqué, M., 2016: Randomly correcting model errors in the ARPEGE-Climate v6. 1 component of CNRM-CM: applications for seasonal forecasts, Geoscientific Model Development,9, 2055-2076, doi:10.5194/gmd-9-2055-2016

5. Forecast system and hindcasts


Forecast frequencymonth
Forecast ensemble size51
Hindcast years1993-2016
Hindcast ensemble size25
On-the-fly or static hindcast set?static


6. Other relevant information

The hindcast/forecast ocean initial conditions are calculated with Mercator-Ocean PSI2G4R1 software..

The forecast uses three start dates:

  • The 20th of the previous month (25 members in the forecasts, 12 members in the hindcasts)
  • The 25th of the previous month (25 members in the forecasts, 12 members in the hindcasts)
  • the 1st of the month (1 member in the forecast/hindcast)

7. Where to find more information


Technical implementation details can be found in http://www.umr-cnrm.fr/IMG/pdf/system6-technical.pdf