Preprints
https://doi.org/10.5194/hess-2021-503
https://doi.org/10.5194/hess-2021-503

  19 Oct 2021

19 Oct 2021

Review status: this preprint is currently under review for the journal HESS.

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

Paola Mazzoglio1, Ilaria Butera1, Massimiliano Alvioli2, and Pierluigi Claps1 Paola Mazzoglio et al.
  • 1Department of Environment, Land and Infrastructure Engineering, Politecnico di Torino, Torino, 10129, Italy
  • 2Istituto di Ricerca per la Protezione Idrogeologica, Consiglio Nazionale delle Ricerche (CNR), Perugia, 06128, Italy

Abstract. The dependence of rainfall on elevation has frequently been documented in the scientific literature and may be relevant in Italy, due to the high degree of geographical and morphological heterogeneity of the country. However, a detailed analysis of the spatial variability of short-duration rainfall extremes and their connection to the landforms does not exist. Using a new, comprehensive and position-corrected rainfall extreme dataset (I2-RED), we present a systematic study of the relationship between geomorphological forms and the average of rainfall extremes (index rainfall) across the whole of Italy. We first investigated the dependence of sub-daily rainfall depths on elevation and other landscape indices through univariate and multivariate linear regressions. After analyzing the results, we repeated the analysis on geomorphological subdivisions of Italy. The results of the national-scale regression analysis did not confirm the assumption of elevation being the sole driver of the variability of rainfall extremes. The longitude, latitude, distance from the coastline, morphological obstructions and mean annual rainfall resulted to be significantly related to the index rainfall, and to play different roles for different durations (1- to 24-hours). However, when comparing the results of the best multivariate regression models with univariate regressions for morphological subdivisions, we found that “local” rainfall-topography relationships within the geomorphological subdivisions outperformed the country-wide multiple regressions and offered a reasonable representation of the effect of morphology on rainfall extremes.

Paola Mazzoglio et al.

Status: open (until 14 Dec 2021)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on hess-2021-503', Francesco Marra, 12 Nov 2021 reply

Paola Mazzoglio et al.

Paola Mazzoglio et al.

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Short summary
We have analyzed the spatial dependence of rainfall extremes upon elevation and topography in Italy. Regression analyses show that previous rainfall-elevation relations at national scale can be substantially improved with new data, both using topography attributes and constraining the analysis within areas stemming from geomorphological zonation. Short-duration mean rainfall depths can be then estimated, all over Italy, using different parameters in each area of the geomorphological subdivision.