Journals Information
Universal Journal of Geoscience(CEASE PUBLICATION) Vol. 1(1), pp. 28 - 36
DOI: 10.13189/ujg.2013.010104
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An Experimental Stochastic Model of the El Ni帽o 鈥� Southern Oscillation System at Climatic Time Scales
Victor Privalsky1,*, Sergey Muzylev2
1 N.N. Zubov State Oceanographic Institute, Moscow, 119034, Russian Federation
2 P.P. Shirsov Institute of Oceanology, Russian Academy of Sciences, Moscow, 117218, Russian Federation
ABSTRACT
An explicit bi-variate stochastic model of the El Ni帽o 鈥� Southern Oscillation system (ENSO) is built for the first time directly from observations of the Southern Oscillation Index (SOI) and sea surface temperature (SST) in the Ni帽o region 3.4 (1876-2011). According to the resulting stochastic difference equation, the system remembers its past for two years, has the eigenfrequency 0.24 year-1 and the damping factors 0.5 and 0.05. Statistics of SST variations, including properties of El Ni帽o and La Ni帽a, are also estimated through a Monte Carlo experiment. The time-domain model is used to describe ENSO in the frequency domain, including maximum entropy estimates of spectra, coherent spectra, coherence function, and frequency response function. The spectra are peaked at 0.22 year-1; the coherence increases from 0.6 at the lowest frequencies to over 0.9 between 0.18 year-1and 0.33 year-1 exceeding 0.8 at all frequencies above 0.12 year-1. This means that SST and SOI determine each other by up to 85% everywhere but at the lowest frequencies. The gain factor is peaked at 0.24 year-1 while the phase factor鈥檚 magnitude is close to 蟺 everywhere. Therefore, the statistical predictability of the bi-variate ENSO time series does not improve much over the scalar case predictability.
KEYWORDS
ENSO, Multi-variate Time Series, Time and Frequency Domain Analysis
Cite This Paper in IEEE or APA Citation Styles
(a). IEEE Format:
[1] Victor Privalsky , Sergey Muzylev , "An Experimental Stochastic Model of the El Ni帽o 鈥� Southern Oscillation System at Climatic Time Scales," Universal Journal of Geoscience(CEASE PUBLICATION), Vol. 1, No. 1, pp. 28 - 36, 2013. DOI: 10.13189/ujg.2013.010104.
(b). APA Format:
Victor Privalsky , Sergey Muzylev (2013). An Experimental Stochastic Model of the El Ni帽o 鈥� Southern Oscillation System at Climatic Time Scales. Universal Journal of Geoscience(CEASE PUBLICATION), 1(1), 28 - 36. DOI: 10.13189/ujg.2013.010104.