Investigating the changes in extreme rainfall in Sicily

Abstract

Changes in extreme rainfall are one of the most relevant sign of current climate alterations. Many studies have demonstrated an increase in rainfall intensity and a reduction of frequency in several areas of the world. This could be probably due to an acceleration of the hydrological cycle caused by temperature increase and could have, as consequence, the increase of flooding hazard. In the past, Sicily has been screened for several signals of possible climate change. Annual, seasonal and monthly rainfall data in the entire Sicilian region have been analyzed, showing a global reduction of total annual rainfall, which is mainly due to the winter reduction. Moreover, some annual maximum rainfall series of different durations have been analyzed in order to detect the presence of linear and non-linear trends. Results indicated that for short durations, historical series generally exhibit increasing trends while for longer durations the trends are mainly negative. Starting from these previous assessments, the aim of this study is to investigate and quantify changes in extreme rainfall in Sicily. Here the entire regional database of annual maximum rainfall series relative to different durations has been analyzed in order to identify the presence of significant trends at site. Moreover, in this study also the daily rainfall series, recorded in the whole Sicily, have been analyzed. This study classifies the daily rainfall in six classes as function of the intensity and then analyzes how the events relative to each class change in time in terms of occurence and intensity.