120 research outputs found
"Corrigendum to ""Coupling of high-resolution meteorological and wave models over southern Italy"", published in Nat. Hazards Earth Syst. Sci., 9, 1267?1275, 2009"
No abstract availabl
A meteo-hydrological prediction system based on a multi-model approach for precipitation forecasting
International audienceThe precipitation forecasted by a numerical weather prediction model, even at high resolution, suffers from errors which can be considerable at the scales of interest for hydrological purposes. In the present study, a fraction of the uncertainty related to meteorological prediction is taken into account by implementing a multi-model forecasting approach, aimed at providing multiple precipitation scenarios driving the same hydrological model. Therefore, the estimation of that uncertainty associated with the quantitative precipitation forecast (QPF), conveyed by the multi-model ensemble, can be exploited by the hydrological model, propagating the error into the hydrological forecast. The proposed meteo-hydrological forecasting system is implemented and tested in a real-time configuration for several episodes of intense precipitation affecting the Reno river basin, a medium-sized basin located in northern Italy (Apennines). These episodes are associated with flood events of different intensity and are representative of different meteorological configurations responsible for severe weather affecting northern Apennines. The simulation results show that the coupled system is promising in the prediction of discharge peaks (both in terms of amount and timing) for warning purposes. The ensemble hydrological forecasts provide a range of possible flood scenarios that proved to be useful for the support of civil protection authorities in their decision
High resolution simulations of a flash flood near Venice.
Abstract. During the MAP D-PHASE (Mesoscale Alpine Programme, Demonstration of Probabilistic Hydrological and Atmospheric Simulation of flood Events in the Alpine region) Operational Period (DOP, 1 June–30 November 2007) the most intense precipitation event observed south of the Alps occurred over the Venice Lagoon. In the early morning of 26 September 2007, a mesoscale convective system formed in an area of convergence between a south-easterly low level jet flowing along the Adriatic Sea and a north-easterly barrier-type wind south of the Alps, and was responsible for precipitation exceeding 320 mm in less than 12 h, 240 mm of which in only 3 h. The forecast rainfall fields, provided by several convection resolving models operated daily for the D-PHASE project, have been compared. An analysis of different aspects of the event, such as the relevant mechanisms leading to the flood, the main characteristics of the MCS, and an estimation of the predictability of the episode, has been performed using a number of high resolution, convection resolving models (MOLOCH, WRF and MM5). Strong sensitivity to initial and boundary conditions and to model parameterization schemes has been found. Although low predictability is expected due to the convective nature of rainfall, the forecasts made more than 24 h in advance indicate that the larger scale environment driving the dynamics of this event played an important role in favouring the achievement of a relatively good accuracy in the precipitation forecasts
How to better exploit the use of LCA analysis for Ultra High Performance Concrete (UHPC) through a constitutive law which integrates chloride and sulfate attack
Structural applications of advanced cementitious materials such as Ultra High Performance Concrete (UHPC) have been already assessed in harsh exposure conditions with presence of chlorides or sulfates. Nevertheless, the limited availability of design standards has not favoured so far a widespread use of these materials. Moreover, previous studies employed a constitutive model only partially representative of the real behavior of such materials when exposed to aggressive conditions. Therefore, this work, employing a “scenario dependent” constitutive law, estimates the serviceability limit state in correspondence of which it is needed to carry out the maintenance activities and investigates, through the Life Cycle Assessment (LCA) methodology, the ecological and economic profile of a UHPC water basin structure subjected to chloride and sulfate attack. The CML impact assessment method has been employed for the specific purpose to compare such structure to one made with ordinary reinforced concrete (ORC) using as system boundary the A1-B7 stages indicated in EN 15804
Crack healing under sustained load in concrete: An experimental/numerical study
The need of sustainable resilient structures and infrastructures push towards the use of cementitious materials able to heal micro-cracks and defects. For real structural application under service loading the time-dependent behavior is of the utmost importance, especially in presence of cracks which can lead to a nonlinear creep behavior that might cause the structural failure. Now the new challenge is to study and quantify the effect of crack-healing on the nonlinear creep behavior. This study aims at the following goals: 1) to characterize with experimental investigations the effect of the healing in tests in which the specimens, along the exposure time and under controlled environmental conditions, are under sustained load, the expected service load, determined as a fraction of the pre-cracking load; 2) develop a comprehensive numerical framework for the interpretation and simulation of the experimentally observed results. To this purpose an experimental investigation is currently ongoing at Politecnico di Milano with reference to an Ultra High-Performance Concrete developed in the framework of the H2020 ReSHEALience project for exposure to extremely aggressive environments. The numerical framework is based on the recent developments of the multiphysics lattice particle model
Overview of the first HyMeX Special Observation Period over Italy: observations and model results
Abstract. The Special Observation Period (SOP1), part of the HyMeX campaign (Hydrological cycle in the Mediterranean Experiments, 5 September–6 November 2012), was dedicated to heavy precipitation events and flash floods in the western Mediterranean, and three Italian hydro-meteorological monitoring sites were identified: Liguria–Tuscany, northeastern Italy and central Italy. The extraordinary deployment of advanced instrumentation, including instrumented aircrafts, and the use of several different operational weather forecast models, including hydrological models and marine models, allowed an unprecedented monitoring and analysis of high-impact weather events around the Italian hydro-meteorological sites. This activity has seen strong collaboration between the Italian scientific and operational communities. In this paper an overview of the Italian organization during SOP1 is provided, and selected Intensive Observation Periods (IOPs) are described. A significant event for each Italian target area is chosen for this analysis: IOP2 (12–13 September 2012) in northeastern Italy, IOP13 (15–16 October 2012) in central Italy and IOP19 (3–5 November 2012) in Liguria and Tuscany. For each IOP the meteorological characteristics, together with special observations and weather forecasts, are analyzed with the aim of highlighting strengths and weaknesses of the forecast modeling systems, including the hydrological impacts. The usefulness of having different weather forecast operational chains characterized by different numerical weather prediction models and/or different model set up or initial conditions is finally shown for one of the events (IOP19)
The RISKMED project : philosophy, methods and products
This paper presents RISKMED, a project targeted to create an Early Warning System (EWS) in case of severe or extreme weather events in the central and eastern Mediterranean and specifically in southern Italy, northwestern Greece, Malta and Cyprus. As severe or extreme weather events are considered, cases when the values of some meteorological parameters (temperature, wind, precipitation) exceed certain thresholds, and/or a severe weather phenomenon (thunderstorm, snowfall) occurs. For an accurate weather forecast, selected meteorological models have been operated daily, based on a nesting strategy using two or three domains, providing detailed forecasts over the above mentioned areas. The forecast results are further exploited for the evaluation and prediction of human discomfort and fire weather indices. Finally, sea wave models have also been operating daily over the central and eastern Mediterranean Sea. In case a severe or extreme weather event is forecasted within the next 48 or 72 h for selected target areas (sub-regions defined by their morphological and population characteristics), the local authorities and the public are informed via a user-friendly graphic system, the so-called RISK MAP. On the web page of the Project (http://www.riskmed.net), additional information is provided about the real-time values of some meteorological parameters, the latest satellite picture and the time and space distribution of lightning during the last 24 h. The RISKMED project was financed by the EU and the Ministries of National Economy of Greece, Italy, Malta and Cyprus, in the frame of INTERREG IIIB/ARCHIMED programme.peer-reviewe
Multidisciplinary assessment and prediction tools addressing coastal vulnerability to erosion and sea level rise. Lesson learnt from the RITMARE Project
Natural processes and human activities are strongly connected, and sometimes con icting, in the evolution of coastal and transitional environments. The strong anthropic pressure on coastal regions, together with the e ects of a changing climate, demands nowadays more pressingly for e cient tools to characterise and predict the behaviour of such systems in order to de ne appropriate response strategies. This requires a deep understanding of the connections among di erent drivers and di erent scales, a multidisciplinary challenge in which heterogeneous data, approaches and scales need to be framed within a consistent dynamical description.
To this aim, a speci c research line was dedicated to \u201cCoastal Vulnerability to Erosion and Sea Level Rise\u201d within the RITMARE Project, supported by the Italian Ministry of University and Research with the purpose of integrating the Italian Marine community in shared research elds in the period 2012-2017. The activities carried out in this framework have been moving along interconnected branches tackling the themes related with sea level rise, ocean modelling, and geomorphological assessment in present conditions and in di erent climate change scenarios, with an eye on the exploitation of marine sand as a strategic resource.
In this contribution we review the main outcomes of this multidisciplinary and coordinated research. Besides discussing the advances and the possibilities from state-of-the art technologies and methodologies, we point out that a coordinated use of the described tools should be promoted in the design of survey and monitoring activities, as well as in the exploitation of already collected data. Expected outcomes of this strategy include the implementation of improved policies and infrastructures for coastal protection, anked by reliable short-term forecasting systems and e cient rapid response protocols, in the framework of an integrated coastal planning at the multi-decadal scale
Assessing the coastal hazard of Medicane Ianos through ensemble modelling
On 18 September 2020, Medicane Ianos hit the western coast of Greece,
resulting in flooding and severe damage at several coastal locations.
In this work, we aim at evaluating its impact on sea conditions and the
associated uncertainty through the use of an ensemble of numerical
simulations. We applied a coupled wave–current model to an unstructured
mesh, representing the whole Mediterranean Sea, with a grid resolution
increasing in the Ionian Sea along the cyclone path and the landfall
area. To investigate the uncertainty in modelling sea levels and waves
for such an intense event, we performed an ensemble of ocean
simulations using several coarse (10 km) and high-resolution (2 km)
meteorological forcings from different mesoscale models. The performance of the ocean and wave models was evaluated against observations retrieved from fixed monitoring stations and satellites. All model runs emphasized the occurrence of severe sea conditions along the cyclone path and at the coast. Due to the rugged and complex coastline, extreme sea levels are localized at specific coastal sites. However, numerical results show a large spread of the simulated sea conditions for both the sea level and waves, highlighting the large uncertainty in simulating this kind of extreme event. The multi-model and multi-physics approach allows us to assess how the uncertainty propagates from meteorological to ocean variables and the subsequent coastal impact. The ensemble mean and standard deviation were combined to prove the hazard scenarios of the potential impact of such an
extreme event to be used in a flood risk management plan.</p
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