Changes in rainfall characteristics are one of the most relevant signs ofcurrent climate alterations. Many studies have demonstrated an increase inrainfall intensity and a reduction of frequency in several areas of theworld, including Mediterranean areas. Rainfall characteristics may becrucial for vegetation patterns formation and evolution in Mediterraneanecosystems, with important implications, for example, in vegetation waterstress or coexistence and competition dynamics. At the same time,characteristics of extreme rainfall events are fundamental for theestimation of flood peaks and quantiles that can be used in manyhydrological applications, such as design of the most common hydraulicstructures, or planning and management of flood-prone areas.In the past, Sicily has been screened for several signals of possibleclimate change. Annual, seasonal and monthly rainfall data in the entireSicilian region have been analyzed, showing a global reduction of totalannual rainfall. Moreover, annual maximum rainfall series for differentdurations have been rarely analyzed in order to detect the presence oftrends. Results indicated that for short durations, historical seriesgenerally exhibit increasing trends, while for longer durations the trendsare mainly negative.Starting from these premises, the aim of this study is to investigate andquantify changes in rainfall statistics in Sicily, during the second half ofthe last century. Time series of about 60 stations over the region have beenprocessed and screened by using the nonparametric Mann–Kendall test.In particular, extreme events have been analyzed using annual maximumrainfall series at 1, 3, 6, 12 and 24 h duration, while daily rainfallproperties have been analyzed in terms of frequency and intensity, alsocharacterizing seasonal rainfall features. Results of extreme eventsanalysis confirmed an increasing trend for rainfall of short durations,especially for 1 h rainfall duration. Conversely, precipitation events of longdurations have exhibited a decreased trend. Increase in short-durationprecipitation has been observed especially in stations located along thecoastline; however, no clear and well-defined spatial pattern has beenoutlined by the results. Outcomes of analysis for daily rainfall propertieshave showed that heavy–torrential precipitation events tend to be more frequent atregional scale, while light rainfall events exhibited a negative trend atsome sites. Values of total annual precipitation events confirmed a significantnegative trend, mainly due to the reduction during the winter season.
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