ANALYSIS OF A LONG-TERM STRUCTURE OF THE SOUTHERN OSCILLATION INDEX AND EL-NINO EVENTS

A multiscale temporal structure of El Nino-Southern Oscillation (ENSO) characteristics is studied. The ENSO is a global-scale process in the ocean-atmosphere system, which occurs in the tropical zone and affect s the earth's climate. A number of El Nino events in the past 500 year s and temporal variations of the Southern Oscillation index (average m onthly values for 100 years and daily values for 10 years) are analyze d. In addition to conventional methods, a wavelet analysis well suited to the study of nonuniform processes involving periodic and nonperiod ic components interacting over a wide range of scales and the time-del ay embedding technique are used. The periodic components of the proces s, a number of local periodicities, and the time scales within which t he data have a self-similar structure are revealed. As a whole, the pr ocess under study seems to exhibit a combined form of behavior, involv ing both a stochastic and a number of regular components.