Spatial distribution and estimation of rainfall trends and erosivity in the Epitácio Pessoa reservoir catchment, Paraíba, Brazil
Richarde Marques da Silva, Celso Augusto Guimarães Santos, Jorge Flávio Casé Braga da Costa Silva, Alexandro Medeiros Silva, Reginaldo Moura Brasil Neto
Abstract
Abstract The main goals of this study are to better understand the spatial and temporal variabilities in rainfall and to identify rainfall trends and erosivity for the period from 1963 to 1991 in the Epitácio Pessoa reservoir catchment, which is located in Paraíba, northeastern Brazil. This study analyzes annual rainfall trends on a regional scale by using monthly data from 13 rainfall stations. For this purpose, the nonparametric Mann–Kendall and Sen methods were used in the analysis. Descriptive statistics methods and interpolation techniques were also used for spatial–temporal analysis of the annual rainfall. A detailed statistical analysis applied to the time series of all the stations indicates that the rainfall presents substantial annual spatial–temporal variability and a negative trend (decrease) in the mean rainfall at most of the rainfall stations in the catchment during the study period. The results only showed a positive trend for the Soledade and Pocinhos stations. The distribution of positive and negative trends in the Epitácio Pessoa reservoir catchment is extremely irregular, and the changes in the study area are more significant compared to those identified in other studies. Graphic abstract