|Título||Reducing stochasticity in the North Altantic Oscillation index with coupled Langevin equations
Lind, Pedro Gonçalves
Gallas, Jason Alfredo Carlson
|Abstract||We present a critical investigation of the functional relationship between the two pressure time series routinely used to define the index characterizing the North Atlantic Oscillation NAO , well known to regulate global climate variability and change. First, by a standard Markov analysis we show that the standard NAO index based on the pressure difference is not optimal in the sense of producing sufficiently reliable forecasts because it contains a dominating stochastic term in the corresponding Langevin equation. Then, we introduce a variationally optimized Markov analysis involving two coupled Langevin equations tailored to produce a NAO quasi-index having the desired minimum possible stochasticity. The variationally optimized Markov analysis is very general and can be applied in other physical situations involving two or more time series.
|Contido em||Physical review. E, Statistical, nonlinear, and soft matter physics. Vol. 72, no. 5 (Nov. 2005), 056706, 12 p.
Processos de Markov
|Tipo||Artigo de periódico
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