Xavier Chartrand, a doctoral candidate in physical oceanography at the Institute of Marine Sciences (ISMER) at the Université du Québec à Rimouski, has been researching the altimetry of the Saint Lawrence River as part of the SWOT mission for the past year. After earning a bachelor’s degree in physics at Université Laval and a master’s degree in physical oceanography at ISMER, he chose to continue his work on geophysical fluid dynamics and ocean and atmosphere modelling. 

Passionate about water in all its forms, he also enjoys sailing and regularly participates in friendly regattas. Xavier is one of the two recipients of the 2025-2026 Réal-Decoste Scholarship. We met up with him to learn more.

What’s the subject of your research project and what is its context?

When measuring the impacts of climate change, we see that the oceans are getting the worst of it. They’re actually suffering the most harmful effects of the increased greenhouse gasses in the atmosphere, since they’re storing more than 90% of the excess heat introduced into the climate system.
Over the last few decades, science has made considerable progress in the study of ocean variations. We now know that we need to observe the ocean surface more precisely to understand how this heat is redistributed across the planet. However, the exact mechanisms behind these energy exchanges are still poorly understood.
 

To improve our knowledge, the Surface Water and Ocean Topography (SWOT) satellite mission simultaneously observes oceans, lakes, rivers, and transition areas such as estuaries, deltas, and coastlines. This mission will increase our understanding of the interactions between these systems and allow us to evaluate the impacts of increasing water temperature on oceans and coastal environments.
As part of my thesis work at ISMER, I’m participating in the Quebec component of the international SWOT mission. My work focuses on data collected in the Saint Lawrence River. 
 

What is the goal of your research project?

This project aims to deepen our understanding of the physical characteristics of the Saint Lawrence by making maximum use of the data from the SWOT mission. These improvements are essential for understanding the long-term effects of global warming on the Saint Lawrence River system and the connected water bodies. 

This research will also allow us to verify the reliability of the data collected by the SWOT satellite, in order to optimize its applications and to provide input for the models that predict the behaviour of the river.

In addition, it will help improve the methods for observing tides in coastal areas and oceans through altimetry, a technique that measures the elevation of the surface of the water, on Earth, from the satellite.

What led you to develop this project?

The ocean surface acts as an interface between the ocean and the atmosphere, by allowing heat and energy to be exchanged. 
With satellite altimetry, we can get accurate information on bodies of water all over the planet. This data supplies a lot of information on the behaviour of water bodies, so it’s essential for improving numerical models that simulate the ocean and understanding areas that are remote or are complicated to study, such as the Saint Lawrence Estuary.
To anticipate the river’s changes in the coming decades, it’s crucial to expand and improve our database. In my opinion, satellite altimetry is a key method for meeting this challenge.

In fact, my involvement in this project arose from a happy accident: a chance encounter with a member of the scientific community, in a context that was far removed from scientific work. The conversation quickly turned to this innovative subject, which is generating a great deal of enthusiasm in the international community, and which led to this great opportunity.  
 

This project is a way for me to apply my knowledge of this emblematic Quebec water body, which is so well-known and which faces unique challenges. I’m proud to contribute to this international mission by adding a touch of Quebec to it.

Xavier is grateful to the organizations whose support has been essential to his work: “I would like to thank Ouranos and the Fonds de Recherche du Québec for their invaluable financial support. Their backing will allow me to focus on carrying out this major project over the next three years, and it confirms the importance of this research for climate issues in Quebec.”
Master’s and doctoral students can now submit their applications for the 2026-2027 Réal-Decoste Scholarship. The scholarship is worth $40,000 annually, renewable for up to three years for a total of $120,000.