TOC > MSC data > GDPS > GDPS-GEML on MSC Datamart
Experimental Global Environmental eMuLator (GDPS-GEML) data in GRIB2 format
The Global Environmental eMuLator (GEML) is a component of the experimental Global Deterministic Prediction System (GDPS) and is an artificial intelligence (AI)-based weather emulator trained on past atmospheric states.
More specifically, this GEML model is based on data compatible with the ¼°, 13-level version of the GraphCast model (Lam et al. 2023) from DeepMind. It was trained and refined by ECCC, using ECMWF’s ERA5 data (1979-2016) and operational analyses (2016-2021). The weights have been recalculated and are also available to the public.
Forecasts are carried out twice daily, each with a 10-day lead time. It generates the reference large-scale temperature and horizontal wind fields, toward which GDPS’s GEM forecasts are spectrally nudged. The geographical coverage is global with a horizontal resolution of 28 km. Data is available on 13 pressure levels, and employs a uniform latitude–longitude grid with 0.25-degree grid resolution. Six atmospheric variables defined on the 13 pressure levels, along with 4 surface variables are available every 6 hours.
Data location
MSC Datamart data can be automatically retrieved with the Advanced Message Queuing Protocol (AMQP) as soon as they become available. An overview and examples to access and use the Meteorological Service of Canada's open data is also available.
The data is available via the HTTPS protocol. It is possible to access it with a standard browser. In this case, we obtain a list of links giving access to a GRIB2 file.
The data can be accessed at the following address :
https://dd.weather.gc.ca/model_gdps-geml/{RES}/grib2/lat_lon/{HH}/{hhh}/
where :
- RES : Horizontal resolution [25km]
- HHH : UTC time of the beginning of the model run[00, 12]
- hhhh : Forecast time[000, 006, ..., 240]
Technical specification of the grid
Values given to the parameters of the 25km latitude-longitude grid:
| Parameter | Value |
|---|---|
| ni | 1440 |
| nj | 721 |
| resolution | 0.25° |
| orientation iof the grid | 0° W 359.75° E |
File name nomenclature
The files have the following nomenclature:
{YYYYMMDD}T{HH}Z_MSC_GDPS-GEML_{VAR}{LVLTYPE-LVL}{Grille}{resolution}_PT{hhh}H.grib2
where :
- YYYYMMDD : Year, month and day of the beginning of the forecast
- T: Time delimiter according to ISO8601 standards
- HH: UTC run time [00, 12]
- Z: Time zone (UTC time)
- MSC: Constant string for Meteorological Service of Canada, the data source
- GDPS-GEML: Constant string indicating that the data come from the experimental Global Environmental eMuLator (GEML), a component of the experimental Global Deterministic Prediction System (GDPS)
- VAR: Type of variable contained in the file (e.g. AirTemp)
- LVLTYPE-LVL : Vertical level and height [ex: Sfc for the surface, AGL-2m for the height of 2m above ground, IsbL-0850 for the geopotential height at 850mb]
- Grid : Horizontal grid [LatLon]
- resolution : 0.25. Means a resolution of 0.25° (approx. 25km) in longitudinal and latitudinal directions
- PT{hhh}H: Timing according to ISO8601. P, T and H are constant characters for Period, Time and Hour. "hhh" represents the forecast time [000, 006, ..., 240]
- grib2: Constant character string indicating that the format is GRIB2.
Examples of filenames :
- 20250529T12Z_MSC_GDPS-GEML_SpecificHumidity_IsbL-0925_LatLon0.25_PT012H.grib2
- 20250529T00Z_MSC_GDPS-GEML_WindU_AGL-10m_LatLon0.25_PT234H.grib2
List of variables
Notes :
- u (UGRD) and v (VGRD) components of the wind vector are to be resolved relative to the defined grid, in the direction of increasing i and j coordinates. Please refer to Code Table 7 of the GRIB standard for further details.
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