Accueil > Actualités > Séminaires > Séminaire de Alexis Hannart au LOCEAN


Titre : Stochastic oscillators and the low frequency modulation of ENSO intensity
Nom du conférencier : Alexis Hannart
Son affiliation : Institut Franco-Argentin d'Etudes du Climat et ses Impacts, IFAECI, UMI CNRS 3351, Buenos Aires, Argentine
Laboratoire organisateur : IPSL
Date et heure : 01-04-2011 14h30
Lieu : LOCEAN, Tour 45-55, 4ème étage, salle de séminaire
Résumé :

Spectral methods are widely used for the analysis of climatic time series and are important for the detection and characterization of climatic variability. On the other hand, linear and nonlinear oscillators are often proposed as conceptual models for the understanding of variability and its periodic features. As an illustration, the delayed action/recharge oscillator (DAO) is a classic model for the El Niño Southern Oscillation (ENSO). While it is typically assumed that such oscillators are forced by noise, eg that oscillators are stochastic, the detailed spectral properties implied by their stochastic nature remain to some extent unexplored. Here, we propose an analysis of some fine spectral properties of stochastic oscillators. We apply those findings to study the ENSO 3.4 SST time series in an attempt to shed light on some currently debated ENSO features such as the low frequency modulation of its amplitude. We also highlight that stochastic oscillators may be used as building blocks for the development of novel spectral methods.

Ce séminaire a lieu dans le cadre du groupe de Statistiques pour l'Analyse, la Modélisation et l'Assimilation de l'IPSL (SAMA: ).