At the European Meteorological Society Annual Meeting 2025, Lisa Bernini, PhD candidate at the University of Genoa at CIMA Research Foundation, presented CHAPTER, a one-of-a-kind dataset that opens new perspectives in the study of extreme meteorological phenomena in Europe and across the Mediterranean basin. A very high-resolution reanalysis, capable of narrating over forty years of atmospheric history with unprecedented detail, directly connected to the future of satellite research with the Hydroterra+ mission.
The conference thus became an opportunity to weave together past and future: on the one hand the memory of data, on the other the ability to envision new technologies to observe and forecast the water cycle.
CHAPTER: the dataset narrating forty years of extremes
CHAPTER (Computational Hydrometeorology with Advanced Performance to Enhance Realism) is a dynamical reanalysis at 3 km horizontal and hourly resolution for the period 1981–2022. Built through downscaling of the global ERA5 reanalysis, it represents a unique data foundation for studying convection, intense precipitation, and high-impact meteorological events.
According to the analysis presented by Lisa Bernini, during 1981–2022 over the entire European and Mediterranean domain an increase in extreme precipitation was observed, with a mean growth in maximum hourly rainfall of +0.9 mm/h. At the same time, mean temperature rose by +1.3 K. Positive trends are particularly evident across much of the Mediterranean and the North Sea, with increases of up to 50%. Conversely, regions such as western France and the border between Eastern Europe and Russia showed negative trends.
The innovative core of CHAPTER lies in its ability to disentangle the physical mechanisms driving these changes. Through a diagnostic approach, researchers separated the thermodynamic contribution—linked to the enhanced capacity of the atmosphere to retain moisture under higher temperatures—from the dynamic one, related to convective vertical motions. The latter emerges as the dominant factor in shaping the distribution and intensity of extremes.
As Bernini explains: “CHAPTER allows us to observe how atmospheric dynamics play a crucial role in shaping precipitation extremes. It is not only the increase in water vapor in the air, due to higher heat, that makes the difference. It is above all convective processes—with their intensity and frequency—that determine the most relevant impacts on the territory.”
Data and models to understand impacts
The strength of a dataset like CHAPTER does not lie solely in its resolution or statistical accuracy, but above all in its ability to become an operational tool. When integrated with hydrological models, it can support impact analyses of extreme events, from flash flood generation to hydrogeological risk.
The poster presented by Bernini shows how spatial correlations between dynamic components and observations reproduce the distribution of extremes with remarkable accuracy. This makes it a robust reference not only for climate research, but also for operational applications, from spatial planning to civil protection.
“Forty years of high-resolution data,” states Bernini, “represent a heritage that allows us not only to better understand the past, but also to establish robust scientific foundations for future forecasting and risk management.”
Hydroterra+: observing water cycle processes from above
The study of the past through CHAPTER directly connects with the future of observational research. Hydroterra+ is the proposed satellite mission, among the four candidate Earth Explorer 12 missions of the European Space Agency, designed to fill one of the largest gaps in the study of the water cycle: the observation of fast-scale processes, on the order of hours to a few days, which are essential to understand and forecast key processes related to the global water cycle, with a particular focus on water vapor, snow, and soil moisture.
Hydroterra+ aims to place in orbit a C-band radar in geostationary position, capable of ensuring continuous, all-weather, high-frequency observations over the Mediterranean region and the Sahel–Volta basin.
These regions, considered climate change hotspots, face increasing exposure to intense hydro-meteorological events, ranging from flash floods to landslides, with direct impacts on the lives of hundreds of millions of people. “The Hydroterra+ mission,” stresses Antonio Parodi, Program Director at CIMA Research Foundation, “represents a qualitative leap forward. It will allow us to observe from above the rapid mechanisms of the water cycle and to transfer this knowledge into forecasting models, thereby improving our ability to anticipate impacts.”
From memory to future: a common thread in research
The connection between CHAPTER and Hydroterra+ is not coincidental: the dataset and the satellite mission are part of the same scientific vision. The former provides a historical reference base, useful for validating and calibrating models; the latter promises new real-time observations, capable of feeding data assimilation systems and improving forecasts.
In this sense, Lisa Bernini’s presentation at EMS 2025 was not only a moment of scientific dissemination, but also a step in a broader research pathway looking ahead. “We need to bring together memory and future,” Bernini concluded, “because only in this way will we be able to build truly effective tools to face the risks linked to a changing climate.”