High frequency intrinsic modes in El Niño/Southern Oscillation Index

Abstract

Recent daily data of the Southern Oscillation Index have been analyzed. The power spectrum indicates major intrinsic geophysical short periods. We find interesting "high frequency" oscillations at 24, 27, 37, 76, 100 and 365 days. In particular the 24 days peaks may correspond to the Branstator-Kushnir wave, the 27 days may be due to the moon effect rotation, the 37 days peaks is most probably related to the Madden and Julian Oscillation. It is not yet clear the explanations for the 76 days which may be associated with interseasonal oscillation in the tropical atmosphere; the 100 days could be resulting from a mere beat between the 37 and 27 periods, or the 76 and 365 days. Next these periods are used to reconstruct the signal and to produce a forecast for the next 9 months, at the time of writing. After cleansing the signal of those periodicities a detrended fluctuation analysis is performed to reveal the nature of the stochastic structures in the signal and whether specific correlation can be found. We study the evolution of the distribution of first return times, in particular between extreme events. A markedly significant difference from the expected distribution for uncorrelated events is found.

Variability of rainfall and temperature (1912–2008) parameters measured from Santa Maria (29°41′S, 53°48′W) and their connections with ENSO and solar activity

“…The Southern Oscillation Index (SOI) is an index used to represent the ENSO phenomena (Petroni and Ausloos, 2008 (Ausloos and Ivanova, 2001). El Niñ o, or warm phase of ENSO, is caused by the heating of water from the East Pacific (Andreoli and Kayano, 2005).…”

Hydrological natural inflow and climate variables: Time and frequency causality analysis

“…The SOI is calculated based on the difference between the atmospheric pressure at sea level in the regions of Tahiti (in the Western Pacific) and Darwin (Australia, Western Pacific) [38]. The Equatorial SOI measures the average difference of atmospheric pressure at sea level between two regions centered on the equator: Indonesia and East Pacific.…”

Statistical mechanics characterization of spatio-compositional inhomogeneity

“…The present SpCoIN measure can be utilized as a complementary tool to traditional ones for analysis of multiscale variability at discrete time scales of any type of time series (even socalled "gappy" ones [18]) with integer valued genuine data or transferable to integer form. Among such exemplary systems one can find intriguing in climatology Southern Oscillation Index [19], fractional Brownian motion analysed recently by Tsallis permutation entropy [20], coarse-grained heart rate data investigated by multiscale entropy and multiscale time irreversibility methods [21], growth models with grains at the film surfaces [22,23], model of surface relaxation with interesting dynamics [24] belonging to so-called zero-range processes reviewed in Ref. [25].…”