Climate change is altering not only the magnitude of temperature and precipitation, but also their seasonal timing. Observations indicate earlier warming over extratropical land (e.g., Stine et al. 2009) and delayed monsoon onset (e.g., Song et al. 2021). These shifts have important implications for water security and ecosystems, yet their underlying mechanisms remain poorly understood. This project will investigate phase shifts in the annual cycle of temperature and precipitation using observations, reanalyses, and the climate model hierarchy. We will first characterize observed shifts using harmonic analysis and onset metrics. To isolate physical drivers, we will then leverage the model hierarchy starting with idealized aquaplanet simulations in a general circulation model. These simulations exhibit a rainy season delay in the tropics even without land-sea contrast, providing a controlled framework to test energetic and dynamical drivers. Emerging hypotheses will then be evaluated across increasing complexity, from simplified land-sea configurations to coupled CMIP6 simulations and large ensembles. This approach will allow us to distinguish thermodynamic from dynamical processes and identify common versus region-specific drivers. Finally, we will quantify the time of emergence of these signals and explore their potential as early indicators of regional climate change. This work will advance understanding of how and why seasonal timing is changing in a warming climate.

The PhD candidate is expected to have a background in physics, math, earth and environmental sciences or related disciplines, as well as experience in the analysis of observational data and/or numerical simulations. Previous training in meteorology, atmospheric physics, oceanography and/or climate dynamics will be considered a plus.

‍

The PhD candidate will work in the vibrant and diverse atmospheric physics group at the University of Trento, with skills and interests ranging from mountain meteorology to climate and large-scale atmospheric dynamics. Unitn hosts the  Masters of Science program in Environmental Meteorology and Climate Physics joint with the University of Innsbruck and offers a wide range of training and seminar activities. The supervisor is involved in several international collaborations and activities, including the recently completed EU-funded NextGEMS project aimed at developing Storm- Resolving Earth System Models, whose output will be leveraged as part of the research project.

‍