IDAF (intensity-duration-area frequency) curves of extreme storm rainfall: a scaling approach

Intensity-duration-area frequency curves, IDAF, are determined for the evaluation of design storms using a scaling approach. The variability of maximum annual rainfall intensity in area and duration is represented through the scaling properties in time and space. Thus the scaling relationships of mean rainfall intensity with area and duration are derived using the concepts of dynamic scaling and statistical self-affinity. For a lognormal distribution of rainfall intensity a multiscaling lognormal model is obtained. This gives the IDAFcurves of extreme storm rainfall. An application is made to the metropolitan area of Milano.