Influenza del clima ondoso e delle mareee sulla posizione della linea di riva: Lido Signorino (Marsala)

La conoscenza della posizione della linea di riva nel tempo è indispensabile per verificare la necessità di opere di difesa e per lo sviluppo di piani di gestione costiera. Essa rappresenta l’intersezione tra la superficie marina e quella terrestre, non è un’entità geometrica fissa, ma varia continuamente a causa del moto ondoso e delle fluttuazioni del livello marino ed è in continuo movimento a causa dei fenomeni di trasporto solido. La maggior difficoltà riscontrata nelle operazioni di rilievo è la determinazione esatta della sua posizione. Risulta pertanto necessaria la comprensione delle caratteristiche del moto ondoso (conoscenza delle mareggiate), dei livelli marini e del profilo trasversale della spiaggia al momento del rilievo. Questo lavoro di ricerca ha come principale obbiettivo l’analisi dell'influenza del clima ondoso e della marea sulla stima della posizione della linea di riva attraverso immagini telerilevate, inoltre viene proposta una nuova metodologia messa a punto su un caso di studio reale. La metodologia proposta ha carattere multi disciplinare, considera infatti, sia aspetti geomorfologici, sia aspetti idraulico marittimi e utilizza strumenti tipici del telerilevamento. Lo studio del clima ondoso è stato condotto a partire dalla mareggiata ordinaria fatta propagare nell'area in studio attraverso un modello di onda spettrale (SWAN: Simulating WAves Nearshore). Inoltre si sono considerate sia le oscillazioni mareali sia la massima altezza raggiunta dall’onda sulla spiaggia emersa (run-up). Il caso in studio ha messo in evidenza gli errori prodotti nella stima della posizione della linea di riva mediante la semplice individuazione della stessa attraverso ortofoto georiferite (1994, 2000, 2006) infatti in tal modo il tracciamento della linea di riva viene eseguito considerando solamente l'interfaccia "asciutto/bagnato". Riportando sulle ortofoto lo spostamento della linea di riva determinato dal clima ondoso associato all’ordinaria mareggiata e riportando anche le massime oscillazioni mareali, si è riscontrato che durante l’intervallo temporale analizzato l’errore aggiuntivo prodotto risulterebbe superiore a 15 m, inficiando l’attendibilità di uno studio diacronico dell'evoluzione della linea di riva

Soil water content assessment: Critical issues concerning the operational application of the triangle method

Knowledge of soil water content plays a key role in water management efforts to improve irrigation efficiency. Among the indirect estimation methods of soil water content via Earth Observation data is the triangle method, used to analyze optical and thermal features because these are primarily controlled by water content within the near-surface evaporation layer and root zone in bare and vegetated soils. Although the soil-vegetation-atmosphere transfer theory describes the ongoing processes, theoretical models reveal limits for operational use. When applying simplified empirical formulations, meteorological forcing could be replaced with alternative variables when the above-canopy temperature is unknown, to mitigate the effects of calibration inaccuracies or to account for the temporal admittance of the soil. However, if applied over a limited area, a characterization of both dry and wet edges could not be properly achieved; thus, a multi-temporal analysis can be exploited to include outer extremes in soil water content. A diachronic empirical approach introduces the need to assume a constancy of other meteorological forcing variables that control thermal features. Airborne images were acquired on a Sicilian vineyard during most of an entire irrigation period (fruit-set to ripening stages, vintage 2008), during which in situ soil water content was measured to set up the triangle method. Within this framework, we tested the triangle method by employing alternative thermal forcing. The results were inaccurate when air temperature at airborne acquisition was employed. Sonic and aerodynamic air temperatures confirmed and partially explained the limits of simultaneous meteorological forcing, and the use of proxy variables improved model accuracy. The analysis indicates that high spatial resolution does not necessarily imply higher accuracies

APPROCCIO CLINICO E RIABILITATIVO AL PAZIENTE PROTESIZZATO D'ARTO INFERIORE

Nella chirurgia sostitutiva protesica, ripercorrendo le tappe riabilitative e analizzandone le modalità e le tecniche, si evince che è possibile permettere al paziente il riapprendimento della corretta deambulazione con la riorganizzazione di tutte le fasi e della gestualità corrente per il reinserimento efficace nel contesto sociale di appartenenza. Oltre che dal punto di vista puramente motorio, il soggetto deve essere seguito anche sotto l’aspetto della psicomotricità e nel rispetto di importanti esigenze psicologiche. Viene sorretto, incoraggiato, ma soprattutto responsabilizzato sul fatto che per la ripresa completa si rende indispensabile la sua partecipazione attiva e la costanza dell’impegno. I riflessi pratici di una guarigione efficace e completa sono quindi estremamente proficui per il soggetto, il quale avverte in sé la capacità di ottemperare all’impegno del proprio recupero; seppur con stati d’ansia che insidiano il suo equilibrio, egli tenderà a proiettarsi nel suo futuro che quindi non apparirà denso di incognite. Non vi sarà commiserazione né emarginazione, ma voglia di vivere in una società che, anche se disumanizza i rapporti fra le differenti fasce di età, offre interessi e spazi per quanti sappiano organizzare la propria esistenza senza frustrazioni, remore e tentennamenti. La riabilitazione del protesizzato è un processo complesso perché non riguarda solamente il recupero della funzionalità della singola articolazione ma è rivolto a un riaddestramento globale del soggetto a una nuova modalità di vita relazionale. Il programma riabilitativo, quindi, deve essere personalizzato sul singolo e deve proporsi obiettivi differenti in base alle condizioni generali (anche cognitive). È necessario rendere possibile il raggiungimento di un livello di autosufficienza e autonomia motoria tale da permettere il ritorno alle normali attività di vita quotidiana

Errata: Mapping soil water content under sparse vegetation and changeable sky conditions: comparison of two thermal inertia approaches

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The impact of soil erosion on soil fertility and vine vigor. A multidisciplinary approach based on field, laboratory and remote sensing approaches

Soil erosion processes in vineyards, beyond surface runoff and sediment transport, have a strong effect on soil organic carbon (SOC) loss and redistribution along the slope. Variation in SOC across the landscape can determine differences in soil fertility and vine vigor. The goal of this research was to analyze the interactions among vines vigor, sediment delivery and SOC in a sloping vineyard located in Sicily. Six pedons were studied along the slope by digging 6 pits up to 60 cmdepth. Soilwas sampled every 10 cm and SOC, water extractable organic carbon (WEOC) and specific ultraviolet absorbance (SUVA) were analyzed. Erosion rates, detachment and deposition areas were measured by the pole height method which allowed mapping of the soil redistribution. The vigor of vegetation, expressed as Normalized Difference Vegetation Index (NDVI), derived from highresolution satellite multispectral data, was compared with measured pruning weight. Results confirmed that soil erosion, sediment redistribution and SOC across the slope was strongly affected by topographic features, slope and curvature. The erosion ratewas 16Mg ha−1 y−1 since the timeof planting (6 years). SOC redistribution was strongly correlated with the detachment or deposition areas as highlighted by pole height measurements. The off-farm SOC loss over six years amounted to 1.2 Mg C ha−1. SUVA254 values, which indicate hydrophobic material rich in aromatic constituents of WEOC, decreased significantly along the slope, demonstrating that WEOC in the detachment site ismore stable in comparison to deposition sites. The plant vigor was strongly correlated with WEOC constituents. Results demonstrated that high resolution passive remote sensing data combined with soil and plant analyses can survey areas with contrasting SOC, soil fertility, soil erosion and plant vigor. Thiswill allowmonitoring of soil erosion and degradation risk areas and support decision-makers in developing measures for friendly environmental management

Power Sensitivity Analysis of Multi-Frequency, Multi-Polarized, Multi-Temporal SAR Data for Soil-Vegetation System Variables Characterization

The knowledge of spatial and temporal variability of soil water content and others soil-vegetation variables (leaf area index, fractional cover) assumes high importance in crop management. Where and when the cloudiness limits the use of optical and thermal remote sensing techniques, synthetic aperture radar (SAR) imagery has proven to have several advantages (cloud penetration, day/night acquisitions and high spatial resolution). However, measured backscattering is controlled by several factors including SAR configuration (acquisition geometry, frequency and polarization), and target dielectric and geometric properties. Thus, uncertainties arise about the more suitable configuration to be used. With the launch of the ALOS Palsar, Cosmo-Skymed and Sentinel 1 sensors, a dataset of multi-frequency (X, C, L) and multi-polarization (co- and cross-polarizations) images are now available from a virtual constellation; thus, significant issues concerning the retrieval of soil-vegetation variables using SAR are: (i) identifying the more suitable SAR configuration; (ii) understanding the affordability of a multi-frequency approach. In 2006, a vast dataset of both remotely sensed images (SAR and optical/thermal) and in situ data was collected in the framework of the AgriSAR 2006 project funded by ESA and DLR. Flights and sampling have taken place weekly from April to August. In situ data included soil water content, soil roughness, fractional coverage and Leaf Area Index (LAI). SAR airborne data consisted of multi-frequency and multi-polarized SAR images (X, C and L frequencies and HH, HV, VH and VV polarizations). By exploiting this very wide dataset, this paper, explores the capabilities of SAR in describing four of the main soil-vegetation variables (SVV). As a first attempt, backscattering and SVV temporal behaviors are compared (dynamic analysis) and single-channel regressions between backscattering and SVV are analyzed. Remarkably, no significant correlations were found between backscattering and soil roughness (over both bare and vegetated plots), whereas it has been noticed that the contributions of water content of soil underlying the vegetation often did not influence the backscattering (depending on canopy structure and SAR configuration). Most significant regressions were found between backscattering and SVV characterizing the vegetation biomass (fractional cover and LAI). Secondly, the effect of SVV changes on the spatial correlation among SAR channels (accounting for different polarization and/or frequencies) was explored. An inter-channel spatial/temporal correlation analysis is proposed by temporally correlating two-channel spatial correlation and SVV. This novel approach allowed a widening in the number of significant correlations and their strengths by also encompassing the use of SAR data acquired at two different frequencie

Particle tracking in a gap of aquatic vegetation meadow

Aquatic vegetation considerably affects the flow field in water bodies, with influence increasing as the depth decreases. As a consequence, vegetation also affects suspended particle transport. In inshore sandy beds less than 40 m deep of the Mediterranean Sea, meadows of Posidonia oceanica are widespread. This plant is constituted by a tuft of very thin and flexible ribbon-like leaves about 1 cm wide and up to 1.5 m long; the meadow areal density can reach 1000-1200 plant/m2. Frequently, such meadows are not continuous but vegetated areas alternate with sand strips (“gaps”). The presence of such discontinuities noticeably affects the flow field and gaps can actually act as particle traps. Some laboratory experiments were performed aiming at studying the flow field in a gap of artificial Posidonia oceanica canopy. In this paper, the measured flow field is used to track single particles within the gap. A simple particle tracking model which assumes no-slip condition and random velocity fluctuations is adopted. A large number of single-particle tracking were performed considering several release elevations of particles as well as several falling velocities of the latters. The examination of the whole tracks allows one to recognize the particle fate as the simulation parameters vary. In spite of the model assumptions, the study gives useful indications on the behavior of a gap towards the suspended particle transport

Power Sensitivity Analysis of Multi-Frequency, Multi-Polarized, Multi-Temporal SAR Data for Soil-Vegetation System Variables Characterization

The knowledge of spatial and temporal variability of soil water content and others soil-vegetation variables (leaf area index, fractional cover) assumes high importance in crop management. Where and when the cloudiness limits the use of optical and thermal remote sensing techniques, synthetic aperture radar (SAR) imagery has proven to have several advantages (cloud penetration, day/night acquisitions and high spatial resolution). However, measured backscattering is controlled by several factors including SAR configuration (acquisition geometry, frequency and polarization), and target dielectric and geometric properties. Thus, uncertainties arise about the more suitable configuration to be used. With the launch of the ALOS Palsar, Cosmo-Skymed and Sentinel 1 sensors, a dataset of multi-frequency (X, C, L) and multi-polarization (co- and cross-polarizations) images are now available from a virtual constellation; thus, significant issues concerning the retrieval of soil-vegetation variables using SAR are: (i) identifying the more suitable SAR configuration; (ii) understanding the affordability of a multi-frequency approach. In 2006, a vast dataset of both remotely sensed images (SAR and optical/thermal) and in situ data was collected in the framework of the AgriSAR 2006 project funded by ESA and DLR. Flights and sampling have taken place weekly from April to August. In situ data included soil water content, soil roughness, fractional coverage and Leaf Area Index (LAI). SAR airborne data consisted of multi-frequency and multi-polarized SAR images (X, C and L frequencies and HH, HV, VH and VV polarizations). By exploiting this very wide dataset, this paper, explores the capabilities of SAR in describing four of the main soil-vegetation variables (SVV). As a first attempt, backscattering and SVV temporal behaviors are compared (dynamic analysis) and single-channel regressions between backscattering and SVV are analyzed. Remarkably, no significant correlations were found between backscattering and soil roughness (over both bare and vegetated plots), whereas it has been noticed that the contributions of water content of soil underlying the vegetation often did not influence the backscattering (depending on canopy structure and SAR configuration). Most significant regressions were found between backscattering and SVV characterizing the vegetation biomass (fractional cover and LAI). Secondly, the effect of SVV changes on the spatial correlation among SAR channels (accounting for different polarization and/or frequencies) was explored. An inter-channel spatial/temporal correlation analysis is proposed by temporally correlating two-channel spatial correlation and SVV. This novel approach allowed a widening in the number of significant correlations and their strengths by also encompassing the use of SAR data acquired at two different frequencie

Analisi multitemporale delle relazioni tra parametri produttivi e indice di vegetazione in viticoltura

L’efficacia degli interventi agronomici dipendono dalla capacità di programmazione in termini di tempo e intensità di intervento. Questultimi aspetti possono essere calibrati tramite una corretta conoscenza delle caratteristiche produttive e qualitative dei parametric di campo e della loro variabilità nel tempo e nello spazio. La viticoltura di precisione fornisce un supporto valido alla definizione della variabilità di campo e temporale dei parametric vegetative e produttivi. Questo lavoro sintetizza due anni di viticoltura di precisione in Sicilia, nelle campagne agronomiche consotte nel 2012 e 2013 in due aziende vitivinicole “Tenute Rapitalà” e “Donnafugata”. L’indice di vegetazione normalizzato, ottenuto da immagini in multispettrale (Rapideye) acquisite nelle fasi di allegagione, pre-invaiatura e maturazione, è stato relazionato con alcuni parametri produttivi alla raccolta (zuccheri e antociani totali) nella cultivar Nero d’Avola allevata a controspalliera. Il lavoro ha lo scopo di evidenziare la forza del legame esistente nei modelli lineari di relazione tra l’indice di vegetazione ed i parametric produttivi e mettere in evidenza: 1) l’epoca migliore per acquisire le immagini da correlare con i parametri produttivi alla raccolta; 2) se le relazioni sono significative tra gli anni oppure necessitano di ricalibrazione; 3) la trasferibilità delle relazioni nello spazio. I risultati confermano le tre ipotesi indagate per il parametro “zuccheri” alla raccolta ma non tutte per “antociani totali”. Questi risultati evidenziano comunque un possible utilizzo predittivo dei modelli di relazione rilevati da satellite e la possibilità di trasferirli nello spazio, quest’ultimo aspetto necessità però di verifiche svolte in pieno campo