1,720,981 research outputs found
Comparazione dei metodi di valutazione della vulnerabilità costiera nella piana del Sele (Salerno).
Full text linkLa ricerca interdisciplinare degli ultimi 20 anni evidenzia il rischio da erosione che colpisce molte coste sottoposte ad arretramento e inondazione da parte delle azioni naturali. Le condizioni critiche di vulnerabilità costiera possono diventare più gravi in particolare nelle pianure costiere, che ospitano importanti centri urbani e industriali, infrastrutture e attività turistiche, spesso accoppiate con paesaggi tutelati e / o siti archeologici. Pertanto è necessaria una corretta valutazione della vulnerabilità costiera, tenendo conto sia della vulnerabilità da inondazioni costiere sia da erosione. In questo lavoro viene valutata la vulnerabilità da eventi meteomarini estremi della piana costiera del Sele (Salerno). La stima della vulnerabilità viene effettuata combinando sia l’erosione a breve termine che quella a lungo termine valutata attraverso una simulazione numerica delle onde e le caratteristiche morfo-sedimentarie della spiaggia. L'analisi dell’evoluzione costiera per effetto della tempesta è stata esaminata per mezzo di due indicatori, calcolati lungo un certo numero di profili di spiaggia realizzati tra il 2008 e il 2009: il wave run-up (come misura di inondazione costiera) e l’arretramento della spiaggia (come misura dell’erosione potenziale). Inoltre, l’evoluzione costiera a lungo termine è stata valutata attraverso i tassi di erosione derivati dal confronto di ortofoto in sequenze multi-temporali e multi-scala. I risultati sono stati espressi utilizzando diversi indici di vulnerabilità costiera, ottenuti sommando i punteggi relativi alla erosione a breve termine ea lungo termine. L'esame dei risultati finali ha evidenziato diverse risposte dei profili costieri in funzione dell’indice utilizzato
Assessment of a geomorphological-based design for coastal protection: The case of a wave-cut platform on the Bogliasco coast (Liguria Region, NW Italy)
No full textCoastal erosion processes and the associated risks pose a significant challenge for coastal urban settlement administrations. Coastal managers are often seeking new approaches and solutions for coastal protection. Introducing protective structures such as breakwaters and groins often poses problems for management, e.g. modification of the natural panorama, changes within the local coastal dynamics and associated implications with regard to coastal hazards and risks. This paper describes a geomorphological-based approach to coastal structure design, taking as its study case the Bogliasco coast in the region of Liguria, near the eastern border of the municipality of Genova (Northwest Italy). Bogliasco is a stretch of rocky coast exposed to the most intense storms of the Liguria Sea and where the urban settlement reaches the edge of the cliff. To prevent cliff collapse and coastal flooding (and mitigate the associated risks), this study proposes an approach based on the structural recovery of an ancient wave-cut platform currently consumed by erosion. The recovered structure dissipates incoming waves, helping to mitigate both the erosive phenomena at the foot of the cliff and the risk of coastal flooding. The performance of the coastal protection project was evaluated by comparing the results of the XBeach model simulations for ante-operam and post-operam scenarios. The results indicate that the adopted solution contributes to a reduction of wave impact on the coast and the mitigation of flood hazards and risks. A geomorphological-based approach is therefore seen as a winning approach from both an engineering and management viewpoint
Cavity detection using a pseudo-3D electric resistivity tomography at the Palaeolithic/Neolithic site of Scaloria Cave, Apulia, Italy: integrated assessment of synthetic and field data sets
No full textA pseudo-3D electrical resistivity tomography (ERT) survey has been carried out to detect cavities at the Neolithic/Palaeolithic site of Grotta Scaloria, close to Manfredonia, Apulia, Italy. Scaloria Cave has a rich history of archaeological research of more than 80 years and is one of the most important Neolithic complexes in the Mediterranean. Synthetic data modelling allowed to check the adequacy of the geophysical method and to develop a proper experimental setup at the survey design stage. Indeed, the results of the field data inversion revealed high resistivity anomalies which can be related to cavities and provided a good definition of the main geological structures and boundaries. Moreover, the results suggest that unknown and speleological unexplored cavities are still present at the Scaloria Cave study site. These findings may provide further insights on pseudo-3D ERT applicability, particularly for cavity detection. Furthermore, the approach used in this study yields fruitful information for further archaeological survey design and for the interpretation of ERT investigations targeting similar geological features and structures
Rip currents investigation on a Ligurian pocket beach, NW Mediterranean
No full textWave-induced currents play a key role in coastal sedimentary and hydrodynamics processes, and in particular, rip currents are probably the most widely studied aspect. Rip currents are characterized by a strong seaward-directed flow, which can transport sediments, planktonic organisms, nutrients, pollutants, and suspended material. However, rip currents are also a hazard for beachgoers and constitute a well known risk to bathers. Several studies have been conducted to describe rip current dynamics and their implications along oceanic beaches, although only a few studies have considered rip dynamics along Mediterranean coasts. This study is an accurate investigation of rip current development in the Levanto pocket beach (Ligurian sea, NW Italy). Coastal video-monitoring, coastal modelling, field surveys, and laboratory analysis are well known methodologies used to study the behaviour of rip currents, but each has its limitations. To overcome this problem, we propose an integrated approach where different tools are integrated among these to obtain mutual validation among several different approaches. The results show how the rip currents investigated in this study can reach and exceed velocities of 1 ms−1, comparable with those of oceanic rip currents, and how these are a key component in the coastal processes that occur along a Mediterranean pocket beach
Detached breakwaters, yes or not? A modelling approach to evaluate and plan their removal
No full textDetached breakwaters have been widely employed as a measure against beach erosion and for coastal protection. However, this type of structures may cause different critical issues, and the advantages are not always evident. Water stagnation, rip currents development in the gaps between multiple structures, and obstruction of the natural panorama are well-recognised issues. However, their removal is always problematic because it is generally associated with rapid erosion of the beach and high costs. This work proposes a modelling approach to obtain a preliminary evaluation of a theoretical removal intervention and discusses its possible consequences. The study case is the Moneglia beach, a tourist beach located on the eastern Ligurian coast, NW Italy. The beach is characterised by the presence of three detached breakwaters, arranged over the entire length of the beach. A dataset consisting of LiDAR data, multibeam data, single-beam data and DGPS data was used to obtain an accurate digital elevation model (DEM) of the study area. Subsequently, the XBeach model was used to simulate three scenarios: i) state-of-the-art scenario (S0), ii) detached breakwaters removal scenario (S1), iii) detached breakwaters removal scenario + nourishment (S1N). The S1 scenario was implemented to evaluate the beach morphodynamic response in the case of a removal intervention. S1N was implemented to simulate a beach recovery plan through a beach nourishment intervention. Once the S1N final scenario was obtained, XBeach was implemented to get a comparison with the sea flooding hazard in the S0 and S1 scenarios. The sea flooding hazard assessment was performed considering storm events with a return time of 50 and 100 years, respectively. The results showed both the potential of the XBeach model as a tool and the sustainability of a theoretical detached breakwater removal intervention
Shoreline measurement obtained with direct and remote techniques on a sandy beach in Gulf of Pozzuoli (Campania)
No full textIn this paper the comparison between video-based and GPS-derived shoreline measurements was performed on a sandy beach located in the Gulf of Pozzuoli (Italy). The comparison between video camera and DGPS coastline has been carried out measuring the error as deviation from the DGPS line computed along the normal to DGPS itself. The deviations between the two dataset were examined in order to establish possible spatial dependence on video camera point of view in the intertidal zone. The results revealed that, generally, the error increases with the distance from the acquisition system. The comparison shows that the proposed model correctly represents the cameras error in coastline image extraction process
The role of Crassostrea gigas (Thunberg, 1793) in the vertical microplastic transfer: A plankton-benthos linkage laboratory protocol
No full textMicroplastics are nowadays recognized as one of the most important pollution sources in the aquatic environment. Their presence has been investigated and certified in various parts of the globe and, most importantly, in a wide variety of species belonging to different trophic levels. However, the process of microplastics vertical distribution among the trophic chains is yet to be disclosed, especially when approaching the plankton-benthos linkage and its consequences in terms of plastic particles transfer from the water column to the benthic biota and environment. We propose a laboratory protocol that simulates microplastics inclusion in organic matter and their subsequent ingestion by the Pacific Oyster Crassostrea gigas (Thunberg, 1793) by the mean of Na-alginate microspheres containing synthetic microplastics. The bivalve sorting mechanisms were also tested by providing phytoplanktonic microalgae and evaluating their proficiency in feeding selectivity. Overall, the Pacific oyster specimens exposed to organic coated microplastics ingested a third (0.1 MP/h vs. 0.3 MP/h) of plastic particles whenever microalgae were available in solution under the same conditions
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
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