Also called El Nino - La Nina , La Nina refers to the cool part of the weather cycle while El Nino is associated with a reversal of global climatic regimes resulting in anomalous floods and droughts throughout the globe. It is of importance to quantify the total pattern of fluctuations for predictability studies. Atmospheric flows therefore exhibit multiple scaling or multifractal structure. The fractal and multifractal nature of fluid turbulence in general and also in atmospheric flows has been discussed in detail by Sreenivasan 2 . The word fractal was first coined by Mandelbrot 3 to describe the selfsimilar fluctuations that are generic to dynamical evolution of systems in nature.
Fractals signify non-Euclidean or fractional Euclidean geometrical structure.
Traditional statistical theory does not provide for a satisfactory description and quantification of such nonlinear variability with multiple scaling. Such multifractal temporal fluctuations in atmospheric flows are associated with selfsimilar multifractal spatial patterns for cloud and rain areas documented and discussed in great detail by Lovejoy and his group 7-9 . Standard meteorological theory cannot explain satisfactorily the observed multifractal structure of atmospheric flows 9 . Selfsimilar spatial pattern implies long-range spatial correlations. Prediction may therefore be possible.