Rainfall and erosivity in the municipality of Rio de Janeiro - Brazil

This study analyzes spatio-temporal variability and erosion potential related to rainfall in the municipality of Rio de Janeiro (MRJ), considering the period of 1997 to 2016. The rainfall series of Alerta Rio system were used, which is composed of 33 rainfall stations. To establish the values of the erosivity index, a linear eq. (Y = a + bx) was used. Ordinary kriging and clustering techniques were used for the spatial analysis of rainfall and erosivity, and the time series were evaluated using parametric tests (Bartlett and Shapiro-Wilk) and descriptive statistics (mean, median, variance, asymmetry, kurtosis and quartiles). It was observed that about 85% of the annual average erosivity is concentrated between the period of September and April, corresponding to the period of greatest probability for erosion impacts occurrence. Results revealed a spatial structure in rainfall, which is directly associated with physiographic aspects of the MRJ and the impacts resulting from urbanization. The Shapiro-Wilk test indicated the predominance of non-significant results for the months of February and November, which is associated to the frequent occurrence of dry spells, atmosphere blockages (February) and transition between the dry and rainy seasons (November).