Volume 81, Number 6, March 2008
Article Number 60001
Number of page(s) 6
Section General
Published online 20 February 2008
EPL, 81 (2008) 60001
DOI: 10.1209/0295-5075/81/60001

Feedback characteristics of nonlinear dynamical systems

A. Lahellec1, S. Hallegatte2, 3, J.-Y. Grandpeix1, P. Dumas4 and S. Blanco5

1  Laboratoire de Météorologie Dynamique, CNRS, Université Paris-VI - Paris, France
2  Centre International de Recherche sur l'Environnement et le Développement, ENPC - Paris, France
3  Ecole Nationale de la Météorologie, Météo-France - Toulouse, France
4  Environment Research and Teaching Institute, Ecole Normale Supérieure - Paris, France
5  Laboratoire Plasma et Conversion d'Energie (LAPLACE, CNRS-UPS), Université de Toulouse - Toulouse, France

received 29 August 2007; accepted in final form 18 January 2008; published March 2008
published online 20 February 2008

We propose a method to extend the concept of feedback gain to nonlinear models. The method is designed to dynamically characterise a feedback mechanism along the system natural trajectory. The numerical efficiency of the method is proved using the Lorenz (1963) classical model. Finally, a simple climate model of water vapour feedback shows how nonlinearity impacts feedback intensity along the seasonal cycle.

05.45.-a - Nonlinear dynamics and chaos.
92.70.Gt - Climate dynamics.

© EPLA 2008