Rainfall Statistical Properties in Naples

In order to collect further information about recent microclimatic changes in urban areas, an analysis of the secular variations of rainfall intensity has been worked out. A significant increase in rainfall due to urbanization process has been ascertained in the last years. A detailed investigation was performed by studying the records of rainfalls, both showery and continuous, in Naples. The rainfalls were separately examined because of their different effect on the city: the former being more localized, the latter generally extending over wide areas. The analysis shows that a major portion of variance in continuous rainfall rate, in cases of static instability and low surface wind intensity, exhibits a persistence that can be described by a first-order Markov process. Moreover, for the continuous rainfalls, a method for possible prediction of the total mean rainfall rate is indicated.