Santander Meteorology Group

A multidisciplinary approach for weather & climate

We have investigated the e®ects of noise on an extended chaotic system using as benchmark the Lorenz'96 model. The analysis of the system's time evolution and its time and space correlations gave us numerical evidence for two distinct stochastic resonance-like behaviors, that become apparent when the signal-to-noise ratio is depicted as a function of the external noise intensity, or the system size. Such phenomena result only weakly sensitive to an external periodic signal. The underlying mechanisms can be associated to a noise induced chaos reduction. Resonant phenomena implications in forecasting are studied exploiting a new method that quanti¯es the reduction of chaos errors' evolution process. A new view of the stochastic resonance phenomenon in a non-stationary situation is shown.