1. Forecast system version
Identifier code: GEM5.2-NEMO
First operational forecast run: 30 June 2024
2. Configuration of the forecast model
Is the model coupled to an ocean model? Yes
Coupling frequency: 30 minutes
2.1 Atmosphere and land surface
| Model | GEM5.2 (atmosphere), ISBA (land) |
|---|---|
| Horizontal resolution and grid | 283×190 Yin-Yang grid (~110 km) |
| Atmosphere vertical resolution | 85 levels |
| Top of atmosphere | 0.1 hPa |
| Soil levels | 2 Layer 1: 0 - 10 cm |
| Time step | 30 minutes |
Detailed documentation:
Diro, G. T. et al. 2024: The Canadian Seasonal to Interannual Prediction System version 3.0 (CanSIPSv3,0). Canadian Meteorological and Environmental Prediction Centre technical note, Environment and Climate Change Canada, https://collaboration.cmc.ec.gc.ca/cmc/cmoi/product_guide/docs/tech_notes/technote_cansips-300_20240611_e.pdf
2.2 Ocean and cryosphere
| Ocean model | NEMO3.6 |
|---|---|
| Horizontal resolution | ORCA1 |
| Vertical resolution | 50 levels |
| Time step | 30 minutes |
| Sea ice model | CICE6 |
| Sea ice model resolution | ORCA1 |
| Sea ice model levels | 5 ice-thickness categories |
| Wave model | N/A |
| Wave model resolution | N/A |
Detailed documentation:
Diro, G. T. et al. 2024: The Canadian Seasonal to Interannual Prediction System version 3.0 (CanSIPSv3,0). Canadian Meteorological and Environmental Prediction Centre technical note, Environment and Climate Change Canada, https://collaboration.cmc.ec.gc.ca/cmc/cmoi/product_guide/docs/tech_notes/technote_cansips-300_20240611_e.pdf
3. Boundary conditions - climate forcings
| Greenhouse gases | Observed annual globally averaged values for CO2, N2O, CH4, CFC11 and CFC12 assembled from several sources including the WMO Greenhouse Gas Bulletin https://wmo.int/publication-series/greenhouse-gas-bulletin |
|---|---|
| Ozone | Monthly climatological latitude and height dependent climatologies based on Fortuin and Kelder (1998) |
| Tropospheric aerosols | N/A |
| Volcanic aerosols | N/A |
| Solar forcing | N/A |
Detailed documentation:
Fortuin J. P. F. and H. Kelder, 1998: An ozone climatology based on ozonesonde and satellite measurements. Journal of Geophysical Research, 103, 31709-31734, doi:10.1029/1998JD200008
4. Initialization and initial condition (IC) perturbations
4.1 Atmosphere and land
| Hindcast | Forecast | |
|---|---|---|
| Atmosphere initialization | ERA5 | ECCC GEPS |
| Atmosphere IC perturbations | Random isotropic perturbations | Ensemble Kalman Filter |
Land Initialization | Off-line ISBA-based Surface Prediction System (SPSv6.2) forced by 1-hourly lowest-level ERA5 fields | ECCC GDPS output adjusted to hindcast climatology |
| Land IC perturbations | None | None |
| Soil moisture initialization | Off-line ISBA-based Surface Prediction System (SPSv6.2) forced by 1-hourly lowest-level ERA5 fields | ECCC GDPS output adjusted to hindcast climatology |
| Snow initialization | Off-line ISBA-based Surface Prediction System (SPSv6.2) forced by 1-hourly lowest-level ERA5 fields | ECCC GDPS output with prescribed climatological snow over Tibetan Plateau |
| Unperturbed control forecast? | None | None |
Detailed documentation:
Gauthier, P., et al. 1999: Background-error statistics modelling in a 3D variational data assimilation scheme: Estimation and impact on the analyses. Proc. ECMWF Workshop on Diagnosis of Data Assimilation Systems, Reading, United Kingdom, ECMWF, 131–145,
Houtekamer, P.L., et al. 2009: Model Error Representation in an Operational Ensemble Kalman Filter. Monthly Weather Review, 137, 2126-2143, https://doi.org/10.1175/2008MWR2737.1
4.2 Ocean and cryosphere
| Hindcast | Forecast | |
|---|---|---|
| Ocean initialization | ORAS5 | CCMEP GIOPS analysis |
| Ocean IC perturbations | None | None |
| Unperturbed control forecast? | None | None |
Detailed documentation:
5. Model Uncertainties perturbations:
| Model dynamics perturbations | None |
|---|---|
| Model physics perturbations |
|
If there is a control forecast, is it perturbed? | No control forecast |
Detailed documentation:
Diro, G. T., et al. 2024: The Canadian Seasonal to Interannual Prediction System version 3.0 (CanSIPSv3,0). Canadian Meteorological and Environmental Prediction Centre technical note, Environment and Climate Change Canada, https://collaboration.cmc.ec.gc.ca/cmc/cmoi/product_guide/docs/tech_notes/technote_cansips-300_20240611_e.pdf
McTaggart-Cowan, R., et al. 2022: Using stochastically perturbed parameterizations to represent model uncertainty. Part I: Implementation and parameter sensitivity. Monthly Weather Review, 150, 2829-2858, https://doi.org/10.1175/MWR-D-21-0315.1
McTaggart-Cowan, R., et al. 2022: Using stochastically perturbed parameterizations to represent model uncertainty. Part II: Comparison with existing techniques in an operational ensemble. Monthly Weather Review, 150, 2859-2882, https://doi.org/10.1175/MWR-D-21-0316.1
6. Forecast system and hindcasts
| Forecast frequency | 12-month forecast is produced on the last day of each month |
|---|---|
| Forecast ensemble size | 20 (ensemble members 1-10 initialized at 00Z on last day of month, 11-20 at 00Z on 5th to last day of month) |
| Hindcast years | 1980-2023 |
| Hindcast ensemble size | 20 (ensemble members 1-10 initialized at 00Z on first day of month, 11-20 at 00Z on 5th to last day of previous month) |
| On-the-fly or static hindcast set? | static |
7. Other relevant information
A significant update between GEM5-NEMO (based on the GEM5.1 AGCM) and GEM5.2-NEMO is that adjustments to the parameterization of non-orographic gravity waves in the tropics in GEM5.2-NEMO has enabled the model to simulate a realistic Quasi-Biennial Oscillation.
Horizontal interpolation from the native model grids to the C3S 1x1-degree grid: bilinear interpolation with filling/masking for land-only and ocean-only fields
Vertical interpolation pressure levels:
- For temp/phi near the surface, log-linear interpolation (linear in ln(eta)) with the lapse rate of 6.5e-3 deg/m
- For remaining variables near the surface and all variables near the top, constant extrapolation, i.e. keep same value from the closest model level
8. Where to find more information
https://weather.gc.ca/saisons/index_e.html
https://climate-scenarios.canada.ca/?page=seasonal-forecasts
