GEOMAR Helmholtz Centre for Ocean Research Kiel
Wischhofstr. 1-3
D-24148 Kiel
Germany
Phone: +49-431 600-0
Fax: +49-431 600-2805
E-mail: info(at)geomar.de
January 27, 2020: Ocean Circulation and Climate Dynamics Colloquium
Prof. Dr. Stephan Pfahl, Weather and Climate Processes, Institute of Meteorology, Freie Universität Berlin, Berlin (Germany): "The influence of latent heating on atmospheric blocking"
11:00, Lecture Hall, Düsternbrooker Weg 20
Large-scale quasi-stationary high-pressure systems, denoted as atmospheric blocking, are a key component of extratropical weather variability and can contribute to various types of extreme weather events. However, the different mechanisms leading to blocking formation and maintenance are not yet fully understood. In this presentation, I will focus on the role that diabatic processes, in particular the release of latent heat associated with cloud formation in strongly ascending airstreams, play in the dynamics and spatio-temporal variability of blocking. Based on a potential vorticity framework, climatological trajectory anaylses and sensitivity experiments with a global circulation model will be used to demonstrate the relevance of such diabatic processes. Finally, first ideas on potential future changes in blocking occurrence due to changes in latent heating in a warming climate will be discussed.
