Regensburg 2013 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 4: Focus Session: Atmospheric and Climate Complexity

DY 4.3: Hauptvortrag

Montag, 11. März 2013, 16:00–16:30, H47

Quantitative approaches to the statistics of extreme events in atmospheric dynamics — •Holger Kantz¹, Jochen Broecker², Leo Granger¹, and Julia Gundermann¹ — ¹Max Planck Institute for the Physics of Complex Systems, Dresden, Germany — ²Dept. Mathematics and Statistics, University of Reading, UK

We discuss various statistical aspects of extreme events based on empirical and theoretical grounds. We consider specifically extreme events caused by the dynamics of the atmosphere such as wind gusts, precipitation events and large temperature anomalies. Relevant quantities are the event rate/return time as a function of event magnitude for very rare events. Whereas data analysis shows that marginal distributions of most types of extremes do not have fat tails and hence extremes are not by orders of magnitudes larger than the standard deviation, correlations in the succession of extremes render large deviation results invalid. One potential theoretical approach to the estimation of the frequency of very rare events is offered by non-equilibrium fluctuation theorems, and we present preliminary results of a study of a two-dimensional hydrodynamical flow. Finally, we discuss predictability and performance of extreme event prediction and show that conclusions depend much stronger on the choice of the performance criterion than anticipated.