Edgar Dolores Tesillos and Stephan Pfahl
Extratropical cyclones are an integral component of midlatitude weather variability and can cause extreme rainfall and windstorms with substantial effects on society. Nevertheless, projections of future changes in cyclone frequencies and intensities are associated with large uncertainties. This project aims to better understand the dynamical processes potentially affecting future cyclone occurrence in the North Atlantic and Mediterranean region. To this end, cyclones in large ensemble simulations of present-day and future climate are investigated based on a potential vorticity perspective and using trajectory analyses.
Lisa Schielicke and Stephan Pfahl
The intensification of heat waves is one the most certain and, at the same time, most impact-relevant consequences of anthropogenic climate warming. However, an accurate assessment of the magnitude of this intensification has to take into account potential changes in the atmospheric circulation patterns associated with heat waves. We use a combination of Eulerian circulation feature analyses and Lagrangian, trajectory-based diagnostics to investigate future changes in heat waves as simulated by climate models from a dynamical perspective.
Projects at ETH Zurich:
Daniel Steinfeld and Stephan Pfahl
Recent research has shown that latent heat release during cloud formation in ascending air streams is a crucial process for the formation of atmospheric blocking that is not probably accounted for in current blocking theories, might lead to model deficiencies in the representation of blocking, and can contribute to future changes in blocking occurrence due to climate warming. In this project, we aim to improve our understanding of this linkage between latent heat release and blocking with the help of Lagrangian diagnostics applied to reanalysis data, global climate simulations and simulations of individual blocking cases with artificially modified latent heat release.
Fabienne Dahinden, Stephan Pfahl, Franziska Aemisegger and Heini Wernli (at ETH/FU Berlin) Christopher Diekmann, Matthias Schneider and Peter Knippertz (at Karlsruhe Institute of Technology)
Moisture transport pathways and processes over the subtropical North Atlantic and Africa are investigated based on a combination of remote sensing observations and model simulations of the isotopic composition of atmospheric water vapour. In this way, it will be evaluated if such isotope observations can serve as additional constraints on the representation of the subtropical water cycle in numerical models.