Department of Earth Sciences

Content:

Atmospheric blockings are significant weather phenomena in the mid-latitudes and are sometimes associated with extreme events. Although they could also occur in a dry atmosphere, there is evidence that moisture processes play an important role in their dynamics as well (Steinfeld, 2019). In particular, surface lows positioned to the west can lead to WCBs (airflows that travel a considerable distance poleward and vertically from the warm air sector), which indirectly strengthen the blocking through the latent heating of the transported air masses.

In a current research project (https://www.geo.fu-berlin.de/met/ag/weclip/projekte/Quasi-Stationary_Atmospheric_States/index.html), a method was developed that can identify such WCBs from trajectory data (Banisch and Koltai, 2017). Compared to previous research, not individual trajectories but spatially coherent "bundles of trajectories" are identified, which corresponds to the classical notion of WCBs.

To date, a discussion of the results has only been based on case studies. In this thesis, a climatology of these will be analyzed and discussed; the dataset will be provided.

Requirements include an interest in weather processes in the mid-latitudes and basic knowledge of a scripting language (Python preferred). Publication of the results may be possible and is encouraged.

Banisch, Ralf and P ́eter Koltai (Mar. 2017). “Understanding the Geometry of
Transport: Diffusion Maps for Lagrangian Trajectory Data Unravel Coherent
Sets”. In: Chaos 27.3, p. 035804. issn: 1054-1500, 1089-7682. doi: 10.1063/
1.4971788.

Steinfeld, Daniel (2019). “The Role of Latent Heating in Atmospheric Blocking:
Climatology and Numerical Experiments”. PhD thesis. Zurich: ETH Zurich.