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Projects

AL CAPONE - Dynamical constraints on regional climate projections of annual precipitation extremes

Patrick Pieper, Stephan Pfahl, Erich Fischer (ETH Zürich) und Donghe Zhu (ETH Zürich)

Jan 01, 2022 — Dec 31, 2024

On a large-scale average, annual extreme precipitation events intensify due to anthropogenic climate change. This intensification has been established on the basis of observations, theoretical considerations, and climate simulations. On a local scale, however, the evidence is, depending on the location, less conclusive because natural climate variability can exert an influence comparable to recent climate change on annual extreme precipitation events. The evidence is further complicated in some regions by large uncertainties in climate projections of annual extreme precipitation. The AL CAPONE project is conducted in cooperation with ETH Zurich and aims to dynamically constrain uncertainties in regional climate projections of annual extreme precipitation.

Characterization and Prediction of Quasi-Stationary Atmospheric States

Henry Schoeller, Stephan Pfahl, Robin Chemnitz, Péter Koltai (University Bayreuth), Maximilian Engel

Dec 01, 2022 — Jun 30, 2026

Atmospheric dynamics in the mid-latitudes features quasi-stationary atmospheric states (QSAS),  also denoted as atmospheric blocking. Despite the existence of a multitude of data-driven  approaches for their identification, a unified mathematical characterization of such states and  the conditions leading to transitions between them is still lacking. We aim to remedy this by  describing and analysing QSAS as persistent dynamical structures both in nonautonomous  deterministic dynamical models and nonstationary non-deterministic dynamical models. This dual view is expected  to elucidate different aspects of the cause, the persistence, and the predictability of QSAS. 

Lagrangian analysis of tracked anticyclonic structures in reanalysis data

Michael Thomas, Stephan Pfahl

May 23, 2022 — May 22, 2026

Summer heatwaves are among the most severe natural disasters and there is great interest in better understanding the physical processes that lead to near-surface extreme temperatures. One phenomenon commonly observed during heatwaves are blocking high-pressure areas, whose persistence appears to favor very high ground temperatures. However, the exact processes involved in the formation of blocking highs or extreme temperatures on the ground are still the subject of current research. Therefore, this study investigates why some high-pressure areas are blocking and others are not, and when exactly extreme temperatures can occur near the ground. Using latest analysis methods and model data from the past 40 years (reanalysis data), high-pressure areas over the European region are identified and their life cycle is examined with regard to the development of near-surface temperatures in their area of influence.

Persistence/abrupt changes in extreme weather events, their responsible processes, and relationships change in a warmer climate

Kalpana Hamal, Stephan Pfahl

Jan 08, 2022 — Jan 08, 2026

People can directly perceive day-to-day (DTD) temperature variation, which measures rapid weather variability and affects human health and the ecosystem significantly. The project aims to explore the historical and future conditions of DTD temperature variations and the persistence/cause of these variations. For this purpose, observation and ensemble simulations of the current and future climate will be examined at seasonal timescales.

The Interaction between Fronts and Convective Cells in the Midlatitudes

Lisa Schielicke, George Pacey, Stephan Pfahl, Rupert Klein (Institut für Mathematik) Daniel Baum (Zuse Institut Berlin)

Mar 16, 2020 — Jun 30, 2026

Scaling cascades in complex systems. Atmospheric convection is a key process in the formation of certain atmospheric hazards such as extreme precipitation, hail and lightning. Convection is controlled by the interaction of various spatial and temporal scales: the synoptic scale, the mesoscale ...

NOTE: the completed projects are here.