306,146 research outputs found
Analysis of extreme events over Mediterranean sea with coupled numerical models
No full textQuesta tesi studia l’applicazione di simulazioni numeriche relative ad eventi estremi, sia atmosferici che oceanici, che si verificano nel bacino del Mediterraneo e che sono fortemente influenzati dall'interazione aerea-mare. Nella prima fase di questo lavoro viene proposta la caratterizzazione fisica degli eventi studiati. I fenomeni studiati sono: i) un evento di Cold Air Outbreak (CAO) avvenuto nell'inverno del 2012 nell'area del Mediterraneo centrale, e in particolare nel nord dell'Italia; ii) un evento di Dense Waters Formation (DWF) prodotta da questo evento CAO; e iii) un evento di "Tropical-Like Cyclone" (TLC) (chiamato "ROLF") che si è sviluppato sulle isole Baleari tra il 6 e il 9 novembre 2011. Inoltre vengono proposti i risultati preliminari di uno studio su un Flood Flash formato sulla Laguna di Venezia. Discuteremo le caratteristiche fisiche che governano questi fenomeni, in particolare l'interazione oceano-atmosfera. Dopo aver descritto questi fenomeni, proponiamo alcune considerazioni sulle applicazioni numeriche necessarie per una corretta simulazione di questi fenomeni, basandoci principalmente su tre approcci numerici. Il primo approccio numerico utilizzato è del tipo "Uncoupled", che consiste nell'uso di modelli atmosferici non accoppiati con modelli oceanici ricavano i dati di SST da datasets satellitari. Il secondo approccio utilizzato si riferisce all'uso di modelli accoppiati di atmosfera-oceano, mentre il terzo presenta l'accoppiamento completo tra atmosfera-oceano ed onde. Lo scopo di queste tecniche di modellizzazione è cercare di descrivere con maggiore precisione i flussi di momento e di calore che si esplicano all’interfaccia aria-mare e che caratterizzano e guidano l’evoluzione di alcuni fenomeni estremi, atmosferici ed oceanici. I risultati mostrano che l'uso di modelli accoppiati fornisce risultati migliori se comparato ad applicazioni non accoppiate, suggerendo spunti significativi per lavori futuri anche nel campo climatologico.This thesis is the result of the work carried out in the three years of course, dealing with the issue of the application of numerical simulations related to extreme events, both atmospheric and oceanic, that appear over the Mediterranean basin and that are strongly influenced by the air-sea interaction. In the first phase of this work the physical characterization of the studied events is proposed. The phenomena studied are i) a case of Cold Air Outbreak (CAO) formed in the winter of 2012 on the central Mediterranean area, and in particular in the north of Italy; ii) a Dense Waters Formation (DWF) produced by this CAO event; and iii) one event of "Tropical-Like Cyclone" (TLC) (called “ROLF”) that developed on the Balearic Islands between the 6th and the 9th of November 2011. Moreover, preliminary results about a Flash Flood formed over the Venice Lagoon are showed in the end of this manuscript. We will discuss the physical characteristics that govern these phenomena, in particular the interaction between sea and atmosphere. After describing and studying the above mentioned phenomena, we propose some considerations regarding the numerical applications that are needed in order to obtain better results. The modeling techniques used for this thesis are mainly three. The first approach used is a classical "Uncoupled", which consists in the use of atmospheric models uncoupled to ocean models and wave models that exploit SST satellite data. The second approach used refers to the use of "Coupled" ocean-atmosphere models, and the third presents the ocean-wave atmosphere coupling. The purpose of these modeling techniques is to try to describe accurately the momentum and heat fluxes that appear at the air-sea interface, and that characterize, very often, some atmospheric and oceanic phenomena. Results show that the use of coupled models provide improved results, having this approach a direct impact mostly on some heat and momentum fluxes and the SST evolution, fundamental in some applications. Moreover, other indirect implications brought along by the use of coupled models, that are often important at the basin scale and regarding also the case of deep marine ventilation, are presented and discussed (Benetazzo et al., 2013, Carniel et al., 2016, Ricchi et al., 2016, Ricchi et al., 2017, Bonaldo et al., 2017)
Towards assessing the Adriatic Sea coastal vulnerability to regional climate change scenarios: preliminary results
No full textPreliminary results from numerical climate simulations of the Adriatic sea at
high resolution (1/25°), performed during two time-slice integrations, are presented
for the period 1960-90 and the 21st century (2070-2100), according to the “A1b”
scenario defined by IPCC.
This aims at addressing the feasibility of downscaling procedure in a regional basin,
resolving features that are generally still not included when using global models and
gaining useful indications on climate-change induced impacts on the wave climate
and ocean circulation.
For this purpose, a fully coupled version of the ROMS-SWAN model has been implemented,
using interpolated meteorological forcings from the SINTA Project (SImulations
of climate chaNge in the mediTerranean Area, a joint scientific cooperation
of CMCC-INGV-Univ. of Belgrade).
Within the Impacts on Soil and Water Division (ISC) of the CMCC, the numerical
downscaling approach is integrated in a GIS-based Decision Support System
(DSS) aimed at the integrated analysis of climate change impacts and risks on coastal
zones at the regional, aimed at guiding decision-makers in the definition of adaptation
strategies.
Despite further experiments are needed to reach definitive results, the outcomes indicate
the feasibility of the numerical downscaling approach; nevertheless, they also
highlight uncertainties intrinsic to this approach that may be leading, at least at the
present state of the art, to results of difficult interpretation.CNR-ISMARPublished3.7. Dinamica del clima e dell'oceanoope
Neural networks and dynamical system techniques for volcanic tremor analysis
No full textA volcano can be seen as a dynamical system, the number of state variables being its dimension N. The state is usually confined on a manifold with a lower dimension f, manifold which is characteristic of a persistent «structural configuration». A change in this manifold may be a hint that something is happening to the dynamics of the volcano, possibly leading to a paroxysmal phase. In this work the original state space of the volcano dynamical system is substituted by a pseudo state space reconstructed by the method of time-delayed coordinates, with suitably chosen lag time and embedding dimension, from experimental time series of seismic activity, i.e. volcanic tremor recorded at Stromboli volcano. The monitoring is done by a neural network which first learns the dynamics of the persistent tremor and then tries to detect structural changes in its behaviour
Towards assessing the Adriatic Sea coastal vulnerability to regional climate change scenarios: preliminary results
No full textPreliminary results from numerical climate simulations of the Adriatic sea at
high resolution (1/25°), performed during two time-slice integrations, are presented
for the period 1960-90 and the 21st century (2070-2100), according to the “A1b”
scenario defined by IPCC.
This aims at addressing the feasibility of downscaling procedure in a regional basin,
resolving features that are generally still not included when using global models and
gaining useful indications on climate-change induced impacts on the wave climate
and ocean circulation.
For this purpose, a fully coupled version of the ROMS-SWAN model has been implemented,
using interpolated meteorological forcings from the SINTA Project (SImulations
of climate chaNge in the mediTerranean Area, a joint scientific cooperation
of CMCC-INGV-Univ. of Belgrade).
Within the Impacts on Soil and Water Division (ISC) of the CMCC, the numerical
downscaling approach is integrated in a GIS-based Decision Support System
(DSS) aimed at the integrated analysis of climate change impacts and risks on coastal
zones at the regional, aimed at guiding decision-makers in the definition of adaptation
strategies.
Despite further experiments are needed to reach definitive results, the outcomes indicate
the feasibility of the numerical downscaling approach; nevertheless, they also
highlight uncertainties intrinsic to this approach that may be leading, at least at the
present state of the art, to results of difficult interpretation.CNR-ISMARPublished3.7. Dinamica del clima e dell'oceanoope
LICHENI E BIOACCUMULO: VERSO UNA NORMA EUROPEA
No full textL'applicazione delle metodologie di biomonitoraggio delle deposizioni di elementi in traccia mediante licheni è sempre più diffusa sia a livello nazionale che internazionale. In Italia tali metodologie, pur non essendo previste esplicitamente dalla legislazione vigente, sono saltuariamente introdotte in procedimenti di VIA e AIA su indicazione di enti locali o territoriali e in passato sono state utilizzate anche in alcuni delicati casi di contenzioso ambientale. A loro supporto esiste una vasta letteratura scientifica, e delle linee guida, mentre mancano dei protocolli riconosciuti dagli enti di normazione. Questa situazione ha suggerito la necessità di
intraprendere un iter di normazione per sviluppare protocolli che uniformino le fasi di progettazione ed esecuzione delle campagne di biomonitoraggio, gli
strumenti per l’interpretazione dei dati e che tutelino coloro che li applicano. Questo intervento si prefigge di descrivere lo stato dell’arte sul bioaccumulo
in licheni autoctoni e trapianti, evidenziando i limiti e i punti di forza delle nostre conoscenze scientifiche e delle metodologie attualmente applicate. Si ritiene che questa fase di analisi critica, che richiede l’apporto di tutti coloro i quali hanno acquisito esperienze in questo settore, sia da completarsi necessariamente prima o almeno contemporaneamente all’inizio del confronto con gli specialisti individuati dall’ente europeo di normazione (CEN) per l’esame del testo in corso di definizione
Spectral precursors of paroxysmal phases of Stromboli
No full textIn this work we investigate the characteristics of the seismicity at Stromboli volcano during more than two years, i.e. from 11 May 1992 to 21 August 1994. The three paroxysmal phases of 1993 mark significant changes in the Strombolian activity; nevertheless, these are not the only ones observed. In fact, the energy content, both in terms of volcanic tremor and of number of events drops to very low values after the periods of intense activity, accompanied by a change in the spectral content of the tremor. However, equally abrupt changes in the frequency content, not accompanied by evident intensity variations, can be observed some weeks after the end of the crises. The volcano seems therefore to behave like a dynamical system with many «quite stable » states with abrupt transitions between them. An interesting observation is the appearance of an energy concentration in the spectral sectors below 3 Hz before more violent eruptive episodes; although the duration of such a phenomenon is variable, it has to be investigated as a possible precursor of potentially dangerous activity of the volcano. A continuous monitoring of the spectral content of volcanic tremor on Stromboli is confirmed to be an essential tool in order to understand the behaviour of Stromboli volcano and to try to forecast its paroxysmal phases
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
On the persistency of crater assignment criteria for Stromboli explosion-quakes
No full textOn the basis of the results of previous works by our group, this paper aims to investigate the correlation between features of a kind of seismic events recorded at Stromboli (the so called explosion-quakes) and the source of such explosions, i.e. the different craters. The purpose is that of finding parameters in order to try an automatic assignment of new events to their crater of origin. These parameters must be searched for both in time and in frequency domain. Afterwards the stability in time of the discrimination is discussed. An important « side effect» of this analysis is the discovery that the percentage of summital explosions not producing seismic signals recordable by a 2 s seismometer is not negligible
Hybris. I limiti dell'uomo tra acque, cieli e terre
No full textLa parola hybris significa violenza, oltraggio, arroganza: è una parola degli uomini e indica la violazione di un limite, di una misura, di fronte agli dei, agli altri uomini, di fronte alla natura. È la violazione di un kosmos e di una armonia, una assenza di consapevolezza e di responsabilità. È avanzare in equilibrio su un filo fragile con la superbia e la sventatezza che lo possono spezzare. Hybris, allora, tra gli entusiasmi della tecnologia e le inquietudini ecologiche diviene una parola adatta per il nostro presente, ne avvertiamo sempre più le conseguenze in ogni nostra azione, sempre più forte il pericolo per la nostra stessa esistenza. È forse buona cosa pensarci. Ne discutiamo in questo libro unendo in maniera inconsueta le parole dei classici antichi e i pensieri della scienza moderna, per cercare di comprendere, a partire dall'idea di Prometeo che ha donato agli uomini il fuoco, le lettere e i numeri, se v'è ancora qualche equilibrio possibile tra la nostra hybris e il mondo che ci circonda
Indicadores para avaliação dos impactos ambientais e sociais das nano-cápsulas e nanopartículas na agricultura.
No full textResumo: A Nanotecnologia oferece a perspectiva de grandes avanços que permitirão melhorar a qualidade de vida e preservar o meio ambiente e os nano-produtos agrícolas ganham espaço com as descobertas de novas aplicações, muitas das quais já disponíveis no mercado. Este projeto visa desenvolver indicadores para avaliação dos impactos ambientais e sociais das nano-cápsulas e nano-partículas utilizadas na agricultura. Estes serão futuramente validados através de consultas a especialistas de áreas correlatas à Nanotecnologia na Agricultura e utilizados no software Impactos NanoAgri
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