Periodicities, tendencies and prevision based on dynamic spectral analysis of the Paraguay river level series in Ladário County (1900/1995)

Abstract

Mean values of monthly and annual level of Paraguay River in Ladário County (1900/1995) were studied by several numerical methods which include: Fourier analysis, periodogram, dynamic spectral analysis and iterative regression. This work intended to identify the main characteristics of the river flow and to use the main periodicities embedded in the series to evidence possible causes or factors which may influence its variations. The river flow is not stationary; however, an attempt was done to use only the eight main periods to predict the river behavior at a time scale of a few decades.