Verso una migliore comprensione della variabilità spaziale degli estremi pluviometrici in Italia

Extreme rainfall is one of the most critical hazards worldwide, and Italy makes no exception: the vulnerability is particularly high due to a high population density associated with complex topography, extended coastlines, and high climate variability. In this work, the first national-scale quality-controlled dataset of sub-daily annual maximum rainfall depths (named Improved Italian - Rainfall Extreme Dataset or I2-RED) is presented and used to carry out an exploratory statistical analysis aimed at identifying extremes that could be considered “critical” in relation to the local climatology. The analysis was then further expanded by investigating the possible presence of temporal trends in the time series. The results confirmed that rainfall extremes of different durations are not increasing uniformly over Italy and that separate tendencies emerge in different sectors, even at close distances. The results summarized in this article provide the basis for improving the rainfall frequency analysis for a future provision of maps of design rainfall for different return periods at the national scale.