Applying the Morlet wavelet in a study of variability of the level of Paraguay river at Ladário, MS

Abstract

The Morlet complex wavelet was used to study the scales when the level of Paraguay River in Ladário (MS) is more variable. A series of daily data of the river, from January 1900 to June 1995, was used. The following relevant results were obtained: (a) important dominant variability was noticed at the annual scale, that was stationary; (b) important variability in the interval of scales from 2 to 5 years, was detected, which was not stationary; (c) another striking variability in the interval of scales from 10 to 11 years, approximately, which was not plainly stationary, was observed; (d) regions were found with lines of phase convergence in the time-scale signal phase analysis diagram. These conclusions are discussed and compared to other investigations on the variability of hydrometeorologic data.