Regional analysis of rainfall-depth-duration equation for South-Italy

The two-component extreme value (TCEV) distribution, which is currently applied in Italy for the regional rainfall and flood frequency analysis, and its hierarchical parameter estimating procedure, are briefly reviewed. Then, a new rainfall-depth-duration equation, based on TCEV distribution and applicable for the hypothesis of both duration-dependent and duration-independent parameter estimates, is proposed. Finally, for the investigated Italian geographical regions (Apulia, Basilicata, Calabria, and Campania), the regionalization procedure is developed, and the rainfall-duration-frequency factor appearing in the rainfall-depth-duration equation is calibrated. The isoline maps of the mean rainfall having a duration equal to 24 h and of the exponent n, appearing in the power equation linking the mean mt of the TCEV distribution with the duration t, are also plotted.