Publications by Author: Chekroun, Mickaël D

2011
Chekroun, Mickaël D., Dmitri Kondrashov, and Michael Ghil. 2011. “Predicting stochastic systems by noise sampling, and application to the El Niño-Southern Oscillation.” Proceedings of the National Academy of Sciences 108 (29): 11766–11771. Abstract

Interannual and interdecadal prediction are major challenges of climate dynamics. In this article we develop a prediction method for climate processes that exhibit low-frequency variability (LFV). The method constructs a nonlinear stochastic model from past observations and estimates a path of the “weather” noise that drives this model over previous finite-time windows. The method has two steps: (i) select noise samples—or “snippets”—from the past noise, which have forced the system during short-time intervals that resemble the LFV phase just preceding the currently observed state; and (ii) use these snippets to drive the system from the current state into the future. The method is placed in the framework of pathwise linear-response theory and is then applied to an El Niño–Southern Oscillation (ENSO) model derived by the empirical model reduction (EMR) methodology; this nonlinear model has 40 coupled, slow, and fast variables. The domain of validity of this forecasting procedure depends on the nature of the system’s pathwise response; it is shown numerically that the ENSO model’s response is linear on interannual time scales. As a result, the method’s skill at a 6- to 16-month lead is highly competitive when compared with currently used dynamic and statistic prediction methods for the Niño-3 index and the global sea surface temperature field.

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2010
Chekroun, Mickaël D., Michael Ghil, Jean Roux, and Ferenc Varadi. 2010. “Averaging of time-periodic systems without a small parameter.” Discrete and Continuous Dynamical Systems 14 (4). American Institute of Mathematical Sciences (AIMS): 753–782.
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Roques, Lionel, and Mickaël D. Chekroun. 2010. “Does reaction-diffusion support the duality of fragmentation effect?” Ecological Complexity 7 (1). Elsevier: 100–106.
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2008
Ghil, Michael, Mickaël D. Chekroun, and Eric Simonnet. 2008. “Climate dynamics and fluid mechanics: Natural variability and related uncertainties.” Physica D 237: 2111–2126.
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