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TOC > MSC Open Data > WCPS > Coupled WCPS ocean-atmosphere on MSC Datamart

Water Cycle Prediction System (WCPS) coupled atmosphere-ocean-sea ice forecasts data in NetCDF format

WCPS-coupled forecast is the component in the Water Cycle Prediction System (WCPS) that provides the coupled atmosphere-ocean-sea ice forecasts at a 1km resolution (0.008 x 0.008 degree) over the Great Lakes, St. Lawrence River and the Gulf of St. Lawrence. It launches 4 times a day at 00, 06, 12, and 18 UTC and produces 84 hours forecast, based on the atmospheric model GEM, coupled with the ocean-ice model NEMO-CICE. The products from WCPS-coupled forecasts are (1) GEM : surface air temperatures, surface wind velocities, and surface runoff (2) NEMO-CICE : variety of lake/ocean sea ice variables, for example, lake levels and temperatures. They are designed to help forecasters issuing bulletins and warnings in ice-infestested waters for navigation, water level alert, emergency response, Search and Rescue, and CIS Sea Ice forecast.

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 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 NetCDF file.

The data can be accessed at the following URLs:

where:

  • HH : Model run start, in UTC [00,06,12,18]
  • hhh : Forecast hour [001, ..., 084]

Technical specification of the grid

Image of the coupled WCPS ocean-atmosphere domain

In the full domain shown in white, the valid dataset that covers lakes and oceans, is in color. In the rest of the domain, a "no-data" mask is used to specify the absence of data.

Parameter Value
ni 6675
nj 2364
resolution at 45° N 1km

Filename nomenclature

NOTE: ALL HOURS ARE IN UTC.

The files have the following nomenclature:

{YYYYMMDD}T{HH}Z_MSC_WCPS_{VAR}_{LVLTYPE}-{LVL}_{grid}{resolution}_PT{hhh}H.nc

where:

  • YYYYMMDD: Year, month and day of the beginning of the forecast
  • T : Time delimiter according to ISO8601 norms
  • HH: UTC run time [00, 06, 12, 18]
  • Z : Time zone (UTC hour)
  • MSC : Constant string indicating that the data is from the Meteorologcal Service of Canada (MSC)
  • WCPS : Constant string indicating that the data is from Water Cycle Prediction System
  • VAR : Variables included in this file
  • LVLTYPE : Vertical level type [Sfc for the surface, DBS for depth below the surface, AGL for fixed height above ground]
  • LVL : Vertical level value [10m, 0.5m, 1.5m, 0-2m from surface to 2 meters, all for all available levels]
  • grid : Constant string indicating the latitude and longitude projection [LatLon]
  • resolution : Resolution in degree 0.008 (about 1km) in both latitude and longitude directions
  • PT{hhh}H: Forecast hours based on ISO8601 norms. P, T and H are constant character designating Period, Time and Hour. "hhh" is the forecast hour [001, 001, 002, ..., 084]
  • nc : constant string indicating the NetCDF format

Examples:

  • 20211208T12Z_MSC_WCPS_SeaIceSnowVol_Sfc_LatLon0.008_PT001H.nc
  • 20211208T12Z_MSC_WCPS_SeaWaterPotentialTemp_DBS-0.5m_LatLon0.008_PT001H.nc

List of variables

Notes:

  • The sossheig variable is generated relative to an arbitrary geoid over the ocean and relative to IGLD85 over the Laurentian Great Lakes. However, water levels in all the Great Lakes are subject to significant biases due to the very construction of the WCPS, which does not benefit from water level assimilation and remains dependent on lake precipitation, river inflows and inter-lake exchanges for its water balance. We therefore encourage users to use the sossheig variable with caution in the Great Lakes region.
  • The unit PSU (Practical Salinity Unit) is equivalent to g/kg or per thousand (‰). It is based on the properties of sea water conductivity.
  • The variables tairsurf, uwindsurf, vwindsurf and runoffsurf are from GEM-LAM and the rests are from NEMO-CICE.

Support

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