A comparative study of rainfall erosivity estimation for southern Italy and southeastern Australia

In this paper, using Sicilian and Australian rainfall intensity data, a com parison between different estimators (modified Fournier index F, F-F index) of the rainfall erosivity factor in the USLE was made. The relationship be tween the modified Fournier index and the mean annual rainfall, P, was theo retically derived. The K constant, linking the F-F index and P, and its cum ulative distribution function (CDF) were used to establish hydrological sim ilitude among different geographical regions of southern Italy and southeas tern Australia. To predict the erasion risk for an event of given average r ecurrence interval, the probability distribution of the annual value E-aj o f the Arnoldus index was studied. In order to establish the theoretical CDF to use as a regional parent distribution, the descriptive ability of LN2 a nd EV1 distributions was studied by both an at-site analysis and a hierarch ical regional procedure. The analysis showed that for each sub-region of so uthern Italy and southeastern Australia, characterized by a constant coeffi cient of variation, the erosion risk index is constant.