I2-RED: A Massive Update and Quality Control of the Italian Annual Extreme Rainfall Dataset

Abstract

The collection and management of hydrological data in Italy has been dealt with at national level, initially, by the National Hydrological Service (SIMN), and at regional level in the last 40 years. This change has determined problems in the availability of complete and homogeneous data for the whole country. As of 2020, an updated and quality-controlled dataset of the historical annual maxima rainfall in Italy is still lacking. The Italian Rainfall Extreme Dataset (I-RED) has recently been created to allow studies to be performed with a homogeneous dataset at a national level. In this paper, the methodological approach adopted to build an improved and quality-controlled version of I-RED (in terms of both the rainfall depth values and the position of the rain gauges) is presented. The new database can be used as a more reliable research support for the frequency analysis of the rainfall extremes. This new I2-RED database contains rainfall annual maxima rainfall of 1, 3, 6, 12 and 24 h from 1916 until 2019, counts 5265 rain gauges and has been corroborated by a re-positioning and elevation-checking of 15% of the stations. A descriptive analysis of the maximum values of the stations, which provides an additional quality check and reveals different intriguing spatial features of Super-Extreme rainfall events, is also presented.

The role of morphology in the spatial distribution of short-duration rainfall extremes in Italy

“…In this paper, we have analyzed the role of orography and morphology in short-duration annual maximum rainfall depths, taking advantage of a new and comprehensive database for Italy, I 2 -RED (Mazzoglio et al, 2020a). The approach finds its relevance in the first use of the most complete and updated data collection of short-duration annual maxima available for the whole Italian territory.…”

“…As the first step of the analysis, we investigated the influence of elevation on the spatial distribution of the average of annual maximum rainfall depths. We calculated the ADD curve parameters for all the stations of the I 2 -RED dataset (Mazzoglio et al, 2020a) to compare them with previous studies (mainly Avanzi et al, 2015). Parameters a and n (cf.…”

“…On the basis of the described background and the significant improvements offered by a new, up-to-date rainfall dataset, i.e., the Improved Italian-Rainfall Dataset, I 2 -RED (Mazzoglio et al, 2020a), the present study has considered more than 3700 stations with at least 10 years of data to relate the average rainfall depths in all the durations (index rainfall) to several morphological variables and investigate their dependency on elevation and on other geomorphological and climatological parameters.…”

“…The authors acknowledge the regional agencies involved in the management of the rain gauge networks that provided the rainfall measurements included in I 2 -RED. Full credits are reported in Mazzoglio et al (2020a).…”

Orographic Precipitation Extremes: An Application of LUME (Linear Upslope Model Extension) over the Alps and Apennines in Italy

“…Unfortunately, this relation cannot be generalized to all seasonal periods and it is generally not valid during the summer when thunderstorm convection generally occurs [53]. A confirmation was made by the authors of [54], who carried out a study for the whole Italian Peninsula based on the Improved Italian-Rainfall Extreme Dataset (I2-RED) [62]. These authors have reported that it is rather difficult to find a generalized orographic precipitation gradient, although their analysis has not given any statistical evidence of a correlation between rainfall and elevation for the Italian Peninsula considering extreme rainfall events.…”