Differential orographic impact on sub-hourly, hourly, and daily extreme precipitation

Formetta, Giuseppe; Marra, Francesco; Dallan, Eleonora; Zaramella, Mattia; Borga, Marco

doi:10.1016/j.advwatres.2021.104085

Cited by 39 publications

(24 citation statements)

References 52 publications

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“…Further analysis considering air temperature and dew-point temperature, could help investigating the physical drivers behind the changes we observe, and could directly address the changes in storm properties, such as duration and total storm amount. In the study area, a recent work by Formetta et al (2022) shows evidence of extremes dependence on elevation. Temporal changes of this dependence are however still unexplored, mostly because of a lack of stations at high altitudes.…”

Section: Discussionmentioning

confidence: 85%

Enhanced Summer Convection Explains Observed Trends in Extreme Subdaily Precipitation in the Eastern Italian Alps

Dallan

Borga

Zaramella

et al. 2022

Geophysical Research Letters

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Understanding past changes in precipitation extremes could help us predict their future dynamics. We present a novel approach for analyzing trends in extremes and attributing them to changes in the local precipitation regime. The approach relies on the separation between intensity and occurrence of storms. We examine the relevant case of the Eastern Italian Alps, where significant trends in extreme precipitation were reported. The model is able to reproduce the observed trends at all durations between 15 min and 24 hr, and allows us to quantify trends in extreme return levels. Despite the significant increase in storm occurrence and typical intensity, the observed trends can be only explained considering changes in the tail heaviness of the intensity distribution, that is the proportion between heavy and mild events. Our results suggest that the observed changes are caused by an increased proportion of summer convective storms.

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Section: Discussionmentioning

confidence: 85%

Enhanced Summer Convection Explains Observed Trends in Extreme Subdaily Precipitation in the Eastern Italian Alps

Dallan

Borga

Zaramella

et al. 2022

Geophysical Research Letters

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“…1), that shorter durations (1-3 h) are characterized by a negative slope coefficient as a function of elevation (statistically significant at a 5 % level), while longer durations (12-24 h) show a positive slope and also a significant correlation, and the trend of the extremes over 6 h loses significance with elevation. Over Trento province, Formetta et al (2022) identified a reverse orographic effect for hourly and sub-hourly durations and an orographic enhancement for a duration of about 8 h (or longer).…”

Section: Introductionmentioning

confidence: 97%

“…Most of the existing studies in Italy have focused on limited areas (Allamano et al, 2009;Caracciolo et al, 2012;Pelosi and Furcolo, 2015;Furcolo et al, 2016;Furcolo and Pelosi, 2018;Libertino et al, 2018;Formetta et al, 2022), (Farr et al, 2007). and the only attempt to deal with sub-daily data covering the entire nation was made by Avanzi et al (2015).…”

Section: Introductionmentioning

confidence: 99%

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

Mazzoglio

Butera

Alvioli

et al. 2022

Hydrol. Earth Syst. Sci.

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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 annual maximum rainfall depths and their connection to the landforms does not exist. Using a new, comprehensive and position-corrected rainfall extreme dataset (I2-RED, the Improved Italian-Rainfall Extreme Dataset), we present a systematic study of the relationship between geomorphological forms and the average annual maxima (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. The results of the national-scale regression analysis did not confirm the assumption of elevation being the sole driver of the variability of the index rainfall. The inclusion of longitude, latitude, distance from the coastline, morphological obstructions and mean annual rainfall contributes to the explanation of a larger percentage of the variance, even though this was in different ways for different durations (1 to 24 h). After analyzing the spatial variability of the regression residuals, we repeated the analysis on geomorphological subdivisions of Italy. Comparing the results of the best multivariate regression models with univariate regressions applied to small areas, deriving from morphological subdivisions, we found that “local” rainfall–topography relationships outperformed the country-wide multiple regressions, offered a uniform error spatial distribution and allowed the effect of morphology on rainfall extremes to be better reproduced.

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“…Extreme precipitation is defined as rainfall where large amounts of rain pour onto the surface in a short amount of time [16][17][18]. At midlatitudes, extreme precipitations can be triggered by atmospheric convection (thunderstorms), explosive cyclones, and atmospheric rivers [1,17,[19][20][21][22][23][24][25]. Here, the orographic effect may cause rainfall intensification [20,21,26], acting as a precursor of convective storm formation, as reported by [21,27].…”

Section: Introductionmentioning

confidence: 99%

“…Here, the orographic effect may cause rainfall intensification [20,21,26], acting as a precursor of convective storm formation, as reported by [21,27]. The rainfall triggered by the orographic uplifting of a humid flow represents one of the most studied mechanisms for precipitation generation [20][21][22][24][25][26]. The difficulties are essentially related to the huge variability of the upslope mechanism that depends on the current local state of the atmosphere and is also strongly connected to the local orography [20,28,29].…”

Section: Introductionmentioning

confidence: 99%

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

Abbate

Papini

Longoni

2022

Water

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Critical hydrometeorological events are generally triggered by heavy precipitation. In complex terrain, precipitation may be perturbed by the upslope raising of the incoming humid airflow, causing in some cases extreme rainfall. In this work, the application of LUME—Linear Upslope Model Extension—to a group of extreme events that occurred across mountainous areas of the Central Alps and Apennines in Italy is presented. Based on the previous version, the model has been “extended” in some aspects, proposing a methodology for physically estimating the time-delay coefficients as a function of precipitation efficiency. The outcomes of LUME are encouraging for the cases studied, revealing the intensification of precipitation due to the orographic effect. A comparison between the reference rain gauge data and the results of the simulations showed good agreement. Since extreme precipitation is expected to increase due to climate change, especially across the Mediterranean region, LUME represents an effective tool to investigate more closely how these extreme phenomena originate and evolve in mountainous areas that are subject to potential hydrometeorological risks.

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Differential orographic impact on sub-hourly, hourly, and daily extreme precipitation

Cited by 39 publications

References 52 publications

Enhanced Summer Convection Explains Observed Trends in Extreme Subdaily Precipitation in the Eastern Italian Alps

Enhanced Summer Convection Explains Observed Trends in Extreme Subdaily Precipitation in the Eastern Italian Alps

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

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

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