Tillys Petit

OS Ocean Sciences

The 2026 Division Outstanding Early Career Scientist Award is awarded to Tillys Petit for outstanding contributions to understanding the ocean processes that regulate the Atlantic overturning circulation, combining observations and modelling to advance climate research.

Tillys Petit has made important contributions to the understanding of ocean processes that regulate the large-scale circulation of the Atlantic Ocean, which play a fundamental role in the Earth’s climate system. Since completion of her doctoral degree in 2019, Petit has established an independent research profile that combines observational analyses and numerical modelling to investigate ocean circulation variability across regional to basin-wide scales. A key contribution of this work is the improved understanding of dense water formation in the subpolar North Atlantic. Petit’s research highlighted the importance of regions outside the Labrador Sea for the production and transformation of dense waters, providing new insight into mechanisms sustaining the Atlantic overturning circulation. These results have helped refine the interpretation of observations and model simulations and have contributed to a broader reassessment of where and how critical water mass transformation processes occur. Additional studies clarified how variability in surface density patterns influences year-to-year changes in dense water formation, advancing understanding of the links between surface forcing and interior ocean circulation. Petit has also contributed to research on the propagation of circulation anomalies and the evaluation of model performance, helping to identify strengths and limitations in the representation of large-scale ocean circulation in climate models. This work supports efforts to improve confidence in assessments of climate variability and change.

Beyond individual scientific results, Petit has taken on responsibilities within international ocean research activities, including co-ordination roles in collaborative programmes focused on ocean circulation monitoring and participation in major oceanographic field campaigns. Contributions have also been made to interdisciplinary initiatives addressing climate variability and early warning indicators, including efforts that explore the use of emerging observation technologies and data-driven methods. In addition, Petit is engaged in mentoring other Early Career Scientists, and in communicating ocean science to a wider audience. These combined activities reflect a strong commitment to high-quality research, scientific collaboration, and service to the geoscience community.