TOC > MSC data > CAPS > CAPS on MSC Datamart
Data from the experimental Canadian Arctic Prediction System (CAPS)
This page describes the experimental atmospheric data in GRIB2 format and oceanic data in NetCDF format from the Canadian Arctic Prediction System (CAPS) available on the MSC Datamart.
Data address
MSC Datamart data can be automatically retrieved with the Advanced Message Queuing Protocol (AMQP) as soon as it becomes available. An overview and examples to access and use Meteorological Service of Canada's open data is also available.
The data is available using the HTTPS protocol and resides in a directory that is plainly accessible to a web browser. Visiting that directory with an interactive browser will yield a raw listing of links, each link being a downloadable GRIB2 or NetCDF file.
The data can be accessed at the following URL:
where :
- HH: UTC run time [00, 12]
- hhh : Forecast hour [000, 001, 002, ..., 048]
Technical specification of the grid
Values given to rotated lat-lon grid parameters at 3km resolution:
| Parameter | Value |
|---|---|
| ni | 2230 |
| nj | 1830 |
| resolution at 60° N | 3 km |
| coordinates of first grid point | 0°N ; 97°W |
Note : The most recent versions of wgrib2 and GDAL support these rotated grids.
Nomenclature of file names
Polar stereographic grid
Files have the following nomenclature:
{YYYYMMDD}T{HH}Z_MSC_CAPS_{VAR}_{LVLTYPE-LVL}_(Grid){resolution}_PT{hhh}H.{format}
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
- CAPS: Constant string indicating that the data come from the Canadian Arctic Prediction System
- VAR: Atmospheric/oceanic variable contained in the file (e.g. AirTemp)
- LVLTYPE-LVL : Vertical level and height [ex: Sfc for the surface, EAtm for the integral of the column, AGL-10m for the height of 10m above ground]
- Grid : Horizontal grid [RLatLon]
- resolution : 0.03. Means a resolution of 0.03° (approx. 3km) 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, 001, 002, ..., 048].
- format: Constant character string indicating the data format contained in the file [
grib2, for the atmospheric variables in GRIB2 format ;nc, for the oceanic variables in NetCDF format]
Examples of file names:
- 20250530T00Z_MSC_CAPS_SnowDepth_Sfc_RLatLon0.03_PT012H.grib2
- 20250603T12Z_MSC_CAPS_SeaIceDivergence_Sfc_RLatLon0.03_PT012H.nc
Variable list
- Atmospheric variables list:
- Oceanic variables list:
Support
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