1,721,041 research outputs found
Modellazione eco-idrologica del ruolo delle radici nell'analisi di stabilità di un versante
No full textEffetto della distribuzione temporale della precipitazione sull’innesco di movimenti superficiali a scala di bacino
No full textAnalisi dell’influenza della risoluzione spaziale di un TIN sulla risposta idrologica a scala di bacino
No full textPreliminary analysis of high-resolution precipitation in Friuli Venezia Giulia region, Italy
Full text linkThe northeastern area of Italy, and specifically of Friuli Venezia Giulia region (FVG), is characterized by the heaviest precipitation annual totals in the country. Effects of both prolonged and extreme precipitation can be particularly damaging in this area, causing debris flow, flash floods, avalanches. Due to the very short times of concentration and hydrological response of the mountain watersheds of the analyzed area, extreme and short events are of particular interest. The region has a dense ground-station network which is managed by the regional Civil Protection Agency, constituted by 2 main rain-gauges networks, based on CAE and Micros-SIAP technology, respectively; this last is co-managed by the OSMER-ARPA (OSservatorio MEteorologico Regionale-Agenzia Regionale per la Protezione dell’Ambiente) FVG. The networks count a total of about 200 rain-gauges; for some stations, data at 5-minute resolution are available since the 1996 (CAE network), whereas Micros-SIAP works continuously and at high resolution since the early 2000s. Over the last two decades, the temporal resolution of stations has been progressively increased up to 1-minute step.
This work presents a comprehensive analysis of the available dataset at high temporal resolution (i.e. 30 min, 5 min and 1 min) to verify whether trends in very short rainfall duration are underway. The continuous time series of data recorded by a sample of rain-gauges by the two networks are first analyzed. A preliminary analysis aims at verifying the consistency of the dataset at the higher resolutions. Statistical trends are then assessed by comparing two methods, i.e., the classical Mann-Kendall and the quantile regression at different thresholds and durations. Differently than the traditional methods that require a subset of data (e.g., the rainfall annual maxima), the quantile regression method allows to detect changes in the tails of the rainfall distributions and to screen the whole rainfall time series
High-resolution rain analysis in FVG, Northeastern Italy
Full text linkThe Julian Alps, located in the region of Friuli Venezia Giulia (FVG, Northeastern Italy), record the heaviest precipitation annual totals in the country. Due to the complex orography and several other prone factors, effects of both prolonged and extreme precipitation can be particularly damaging in this area, causing debris flow, flash floods, avalanches. A proper planning of protection against natural hazards then requires the understanding of possible modification in rainfall characteristics. Since the mountain watersheds of the Alpine area are characterized by a very short time of concentration and hydrological response, extreme events are of particular interest, and rainfall analyses at sub-daily scale could not be appropriate.
The region counts on a dense ground-station network which is managed by the regional Civil Protection Agency, constituted by 2 main rain-gauges networks, based on CAE and Micros-SIAP technology, respectively; this last is co-managed by the OSMER-ARPA (OSservatorio MEteorologico Regionale-Agenzia Regionale per la Protezione dell’Ambiente) FVG. The networks count a total of about 200 rain-gauges; for some stations, data at 5-minute resolution are available since the 1996 (CAE network), whereas Micros-SIAP works continuously and at high resolution since the early 2000s. Over the last two decades, the temporal resolution of stations has been progressively increased up to 1-minute step.
In this work, we propose a comprehensive analysis of the available dataset at high temporal resolution (i.e. 30 min, 5 min and 1 min) in order to verify whether trends in very short rainfall duration are underway. At this aim, we first analyzed the continuous time series of data recorded by a sample of rain-gauges by the two networks. A preliminary analysis aims at verifying the consistency of the dataset at the higher resolutions. Statistical trends are then assessed by comparing two methods, i.e., the classical Mann-Kendall and the quantile regression at different thresholds and durations. The quantile regression method, which is increasingly used in hydrology, allows to detect changes in the tails of the rainfall distributions and to screen the whole rainfall time series, differently than the traditional methods that require a subset of data (e.g., the rainfall annual maxima)
A physically-based and distributed approach to analyze rainfall-triggered landslides at a watershed scale
Full text linkAnalysis of high-resolution rain records in FVG, northeastern Italy
Full text linkThe Friuli Venezia Giulia (FVG) region, northeastern Italy, records the heaviest precipitation annual totals of the country. The region counts on a dense ground-station network constituted by 2 main rain-gauges networks, whose sampling frequency has been progressively increased from 60 up to 1min step. In this work,
we propose a comprehensive analysis of the available dataset of continuous series at high temporal resolution (i.e. 60, 30, 5 and 1min) to verify whether trends in very short rainfalls are underway. We adopt the quantile regression (QR) method which allows to detect changes in the tails of the rainfall distributions and to screen the whole rainfall time series. At this aim, we first introduce a method to check and correct the continuous series by removing the suspicious outliers, based on references values. Significant increasing trends at 5% of significant level have been detected on some of the analysed stations
Analisi preliminare di dati di pioggia ad alta risoluzione in Friuli Venezia Giulia, Italia
No full textIl Friuli Venezia Giulia (FVG) è caratterizzato da una pioggia media annuale che varia da 950 mm nell’area costiera fino a 3150 mm nella zona pre-alpina.
A causa dell'orografia complessa e di altri fattori, gli effetti delle precipitazioni estreme sono particolarmente dannosi. Inoltre, i bacini montani dell'area alpina sono caratterizzati da tempi di concentrazione molto brevi, quindi gli eventi estremi di breve durata sono particolarmente rilevanti.
La regione è dotata di pluviometri di ultima generazione, capaci di registrare dati con una frequenza fino a 1 minuto. Tuttavia, possono sorgere dei problemi legati (i) alla qualità dei dati e (ii) alla lunghezza della serie temporale, spesso non sufficientemente lunghe per essere impiegate in qualsivoglia analisi statistica
Calibrazione di un modello idrologico semi-distribuito per l'analisi delle colate detritiche nel bacino del fiume Fella, Friuli-Venezia Giulia
No full textIl nord-est dell’Italia e, in particolare, la regione del Friuli-Venezia Giulia (FVG) sono caratterizzati da precipitazioni abbondanti ed intense che causano spesso fenomeni di colate detritiche. In particolare, una delle aree maggiormente colpite da colate detritiche riguarda la parte alto-orientale del bacino del fiume Fella, affluente del Tagliamento, che si estende sulle Alpi Giulie. Il lavoro mira a perseguire due obiettivi principali:
i) implementare un framework idro-morfodinamico per l'analisi delle colate detritiche innescate da intense precipitazioni;
ii) sfruttare, per la prima volta, la flessibilità del modello idrologico semi-distribuito GEOframe-NewAge per la simulazione di eventi pluviometrici ad alta risoluzione temporale (5 minuti)
Assessing the solid-liquid discharge and rheological behavior of debris flow. A numerical model of a case study.
Full text linkThe Friuli Venezia Giulia (FVG) region, located in the northeast of Italy, is characterised by frequent heavy precipitations that recurrently trigger debris flow phenomena. On August 2003, an intense rainfall concentrated in the north-eastern Julian Alps of FVG produced several floods and debris flow events, widespread on the entire basin of the Fella river watershed, with great economic damage and some casualties.
In the light of this, forecasting tools for the debris-flow analysis are useful with a view to a territorial planning. The general aim of our research is to develop a hydro-morphodynamical framework to study debris flow phenomena, which includes the hydrological modelling of the rainfall triggering event, the estimate of the solid-liquid discharge of the debris-flow and the hydraulic modelling of its propagation.
While previous works have accomplished the hydrological analysis, in the present study we focus on the evaluation of the solid-liquid discharge and the simulation of its propagation down the slope till its stop. Specifically, we considered a sub-basin of the Fella river watershed, the Uque at Ugovizza, and, in particular, a sub-area of the basin from which the debris flow that swept the village of Ugovizza in 2003 came off. The resulting liquid discharge obtained from the previous hydrological analysis was the input data to derive the solid-liquid discharge of the debris flow, which was assessed by using a formulation proposed in literature.
In order to study the propagation of the debris flow, we first identified a rheology model suitable to represent this kind of events. This was then implemented into an in-house numerical model, which integrates the bidimensional shallow water equations by means of finite volume techniques. Furthermore, an appropriate runout criterion was also assessed, so that the final stages of the phenomenon can be represented.
The first results of the application of the developed hydro-morphodynamic framework to this case study are presented and discussed
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