Simulation of extreme heat waves with empirical importance sampling

Pascal Yiou (1, 2) , Aglaé Jézéquel (1)

1 LSCE - Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette]
2 ESTIMR - Extrèmes : Statistiques, Impacts et Régionalisation

Simulating ensembles of extreme events is a necessary task to evaluate their probability distribution and analyze their meteorological properties. Algorithms of importance sampling have provided a way to simulate trajecto-ries of dynamical systems (like climate models) that yield extreme behavior, like heat waves. Such algorithms also give access to the return periods of such events. We present an adaptation based on circulation analogues of importance sampling to provide a data-based algorithm that simulates extreme events like heat waves in a realistic way. This algorithm is a modification of a stochastic weather generator, which gives more weight to trajectories with higher temperatures. This presentation outlines the methodology using Eu-ropean heat waves and illustrates the spatial and temporal properties of simulations.

Domaines: Océan, Atmosphère

Pascal Yiou, Aglaé Jézéquel. Simulation of extreme heat waves with empirical importance sampling. Geoscientific Model Development, 2020, 13 (2), pp.763-781. ⟨10.5194/gmd-13-763-2020⟩. ⟨hal-02902925⟩