Following his university study project in numerical method supervised by André Robert, he was hired at ECCC's Numerical Environmental Prediction Research RPN group to work on the development of the first versions of limited-area atmospheric models. Subsequently, his research work was oriented towards numerical environmental prediction by working on the development of the first deterministic forecasting system coupled atmosphere-ocean-ice, as well as the development of the hydrometeorological forecasting system.
Between 2006 and 2022, Pierre was in charge of the RPN group, which is responsible for developing jointly with employees of the Canadian meteorological service, as well as with several partners, the various numerical prediction models (ocean, ice, wave, ground, snow, vegetation, city, river, lake) which are coupled or forced to the GEM atmospheric model.
With Ouranos since 2022, Pierre coordinates the Climate Science and Climate Services Team.