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Data and products of the Water Cycle Prediction System (WCPS)

The Water Cycle Prediction System (WCPS) simulates the complete water cycle, following the water as it moves from the atmosphere to the surface, through the river network and into lakes, and back to the atmosphere. WCPS was implemented over the Laurentian Great Lakes and St. Lawrence River watershed in support of Canada's obligations under the Boundary Waters Treaty (International Joint Commission 2016).

WCPS is a chain of interconnected models. The models represent processes in the atmosphere, at the land surface and in the soil (at 10-km resolution), in large bodies of water and marine ice (at 2-km resolution), and in rivers (at 1-km resolution). WCPS produces two forecasts per day for the next three and a half days (84 hours).

The Regional Deterministic Prediction System (RDPS) provides initial and boundary conditions to a limited area version of GEM-LAM covering eastern North America. Every 7 minutes, GEM-LAM communicates with the ocean-ice model, NEMO-CICE, which is set up on the Great Lakes, namely Lakes Superior, Michigan-Huron, St. Claire, Erie, and Ontario. GEM-LAM informs NEMO of the precipitation that has landed on the surface of the lakes and of the state of the near-surface atmosphere. NEMO informs GEM-LAM of the surface water temperature, the extent of the ice cover, and the fluxes of latent and sensible heat and momentum. GEM-LAM also provides hourly estimates of surface runoff to the river routing model, WATROUTE. In turn, WATROUTE informs NEMO of the terrestrial runoff.


How to access the data

This data is available on the MSC GeoMet API / web services and the MSC Datamart data server:

An overview and examples to access and use the Meteorological Service of Canada's open data is available.


The end-user licence for Environment and Climate Change Canada's data servers specifies the conditions of use of this data.

MSC Open Data Service Usage Policy

The MSC Open Data Service Usage Policy determines what constitutes an acceptable use of MSC Open Data services and provides users best practices for optimal use.


To come.

Technical documentation


The chronology of changes to the Water Cycle Prediction System (WCPS) is available here.