Rescaled Range analysis of pluviometric records in northeast Brazil

We investigate whether the rainfall distribution of a drought prone region is characterized by different scaling properties in comparison to those in temperate regions of the world. We present a Rescaled Range (R/S) analysis of precipitation time series for 21 stations in northeast Brazil. In order to avoid the inclusion of short term variability, the data were smoothed by a moving average procedure. Three different algorithms were applied to the data: the empirical procedure proposed by Hurst; the evaluation of the sta ndard mean deviation around the average profile; the evaluation of the mean deviation around the best fit line. The latter two methods have also been used for the evaluation of the nature of surface irregularities (rugosity) in surface profiles. The results obtained by the R/S method point to an ave rage value H = 0.709 > 0.5. This value indicates that the records show a de gree of persistence quite close to that found for 10 stations in Spain. It also shows that drought occurrence does not alter the persistence of the ra infall distribution.