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Séminaire

Title : Tipping Points Across the Climate Modeling Hierarchy
Name of the speaker : Michael Ghil
Affiliation : ENS / UCLA
Laboratory organizer : LMD
Date and time : 02-03-2021 11h00
Location : En ligne
Summary :

Tipping points (TPs) are everywhere, in particular so in the climate sciences. We define TPs rigorously as a generalization of classical bifurcations to nonautonomous and random dynamical systems. Next, we explain the key concepts of dynamical systems with time-dependent forcing and the methods for a self-consistent study thereof. The obvious motivation for such a study of TPs and of the associated pullback attractors (PBAs) is describing, understanding and predicting the global change of a complex system with many scales of motion, in time and space, like the climate system.

Examples of application will go from the classical Lorenz convection system with multiplicative noise, through an El Niño–Southern Oscillation (ENSO) model subject to the seasonal cycle and a low-order model of the midlatitude oceans’ circulation driven by time-dependent wind, and on to an intermediate, coupled ocean–atmosphere model of the midlatitudes driven by ENSO forcing. If time permits, a brief excursion into coupled climate–economy modeling from this perspective will also be made.


Pour participer : https://www.gotomeet.me/SeminairesGeosciencesENS (et si possible en Froidevaux-E314)

Contact :

helene.rouby@ens.fr