SIGNATURES OF A UNIVERSAL SPECTRUM FOR ATMOSPHERIC INTERANNUAL VARIABILITY IN GOADS SURFACE PRESSURE TIME-SERIES

Annual and seasonal mean global surface pressure time series for the 2 5 years 1964-1988 obtained from the Comprehensive Ocean Atmosphere Dat a Set (GOADS) were subjected to quasi-continuous periodogram spectral analysis. Periodogram estimates are summarized in the following: (i) t he atmospheric interannual variability exhibits a broadband (eddy cont inuum) structure; (ii) the spectra follow the universal inverse power- law form of the statistical normal distribution; (ii) periodicities up to 5 years contribute to as much as 50 per cent of the total variance ; (v) the high- and low-frequency El Nino-Southern Oscillation (ENSO) cycles of respective periodicities 3-4 years and 4-8 years and interde cadal oscillations are present in all the data sets. The inverse power -law form for power spectra is ubiquitous to real-world dynamical syst ems and is identified as a signature of self-organized criticality or deterministic chaos. The above results are consistent with a recently developed cell dynamical system model for atmospheric flows, which pre dicts self-organized criticality as intrinsic to quantum-like mechanic s governing atmospheric flow dynamics. Identification of self-organize d criticality in annual and seasonal mean surface pressure fluctuation s and its unique quantification implies predictability of the total pa ttern of fluctuations. A universal spectrum for interannual variabilit y rules out linear trends in atmospheric surface pressure patterns.