A methodology to classify extreme rainfall events in the western mediterranean area

Summary From a large data set (1927–1992) of rainfall rate in Barcelona, the relationship between maximum rainfall rates for time intervals between 5 minutes and 24 hours has been investigated. Intensity-Duration-Frequency (IDF) curves and their master equation for every return period in Barcelona have been obtained. A cluster analysis has yielded four main classes of extreme rainfall events in this area, corresponding to durations shorter than 35 minutes, 1 hour, 2–6 hours and those longer than 6 hours respectively. An index to classify extreme rainfall events has been proposed. This index gives some information about the severity of storms taking into account the contribution of different scales implied in rainfall processes.