The study of temporal distribution of rainfall is carried out to characterize the most frequent rainfall patterns. Knowledge of the physical characteristics of rainfall in relation to rainfall patterns allows mathematical modeling to be performed in regard to hydrologic events more nearly approaching real conditions. The objective of this study was to characterize the erosive rains from the municipality of Urussanga, SC, Brazil in regard to hydrological patterns of temporal distribution. Rainfall records from the meteorological station of Urussanga (28.31° S latitude, 49.19° W longitude, 49 m altitude) from October/1980 to March/2012 were used. Erosive rainfalls were classified as advanced, intermediate, or late pattern if the greatest intensity occurred in the initial, intermediate, or final third of the rainfall event, respectively. We determined the characteristics of rainfall height in the rain gauge, duration of the rain, kinetic energy, maximum intensity in 30 min, erosivity, and frequency of monthly rainfalls within each rainfall pattern. There were 1,221 erosive rainfalls in the period - 651 with an advanced profile, 416 with an intermediate profile, and 154 with a late profile. The average duration of an erosive rainfall was 14.4 h. The average total for erosive rainfall intensity was 17.4 mm h-1. The highest concentration of rainfall (32.9 %) was observed in the 6 to 12 h range of duration. Rains with a duration of less than 18 h occurred most frequently in the advanced rainfall pattern, and for durations greater than 18 h, the frequencies of advanced and intermediate rainfall patterns were similar.
precipitation; erosivity; hydrological patterns
