Detecting trends of extreme rainfall series in Sicily

摘要

The objective of the study is to assess the presenceof linear and non linear trends in annual maximum rainfallseries of different durations observed in Sicily. In particular,annual maximum rainfall series with at least 50 years ofrecords starting from the 1920’s are selected, and for each duration(1, 3, 6, 12 and 24 h) the Student’s t test and theMann-Kendall test, respectively, for linear and non linear trend detection,are applied also by means of bootstrap techniques.The effect of trend on the assessment of the return period ofa critical event is also analysed. In particular, return periodsrelated to a storm, recently occurred along the East Coast ofSicily, are computed by estimating parameters based on severalsub-series extracted from the whole observation period.Such return period estimates are also compared with confidenceintervals computed by bootstrap. Results indicate thatfor shorter durations, the investigated series generally exhibitincreasing trends while as longer durations are considered,more and more series exhibit decreasing trends.