A study of persistence analysis in climatic data from Salvador – Brazil

Abstract

Fractal geometry has been used frequently to characterize and describe natural models. Its applications range from microscopic dimensions to the understanding of macroscopic processes. Following this principle, we studied a set of climatic data, collected in Salvador, Bahia, through the methods of rescaled analysis and spectral analysis. The time series are physical parameters of precipitation, atmospheric pressure, evaporation, humidity, solar radiation, maximum, minimum and average temperatures collected monthly over a span of 30 years, from 1961 to 1990. For each parameter, we computed the Hurst exponent H and the spectral exponent b, attesting the variability of the available data. The results for H varied between 0.52 and 0.91, for both methods, in such a way that all the parameters behave as persistent. The importance of such study is to show that different methods provide the same results, which is a significant fact for complex systems. The knowledge of H also provides the computation of the fractal dimension, thus allowing us to quantify the complexity of the climatic phenomena.