266 research outputs found
GHG emissions inventory at urban scale: the Sassari case study
No full textWithin current initiatives dedicated to provide information on the status of greenhouse gases emissions, the town of Sassari represents a pilot site for estimating the net exchange of carbon dioxide (emissions and sinks) at municipal level in Sardinia (Italy). A spatial and temporal high resolution greenhouse gas emissions inventory for the urban area of Sassari is currently under construction in line with European and international standard protocols to establish a baseline for tracking emission trends. This paper presents the preliminary results of the development of a simplified local emissions inventory where estimates of the atmospheric emissions are collected and cataloged by type of greenhouse gases, productive activity and emissive source on annual basis
Applicazione dei laser scanner terrestri in campo agro-forestale e ambientale
No full textLe tecniche di laser scanning terrestre suscitano un interesse sempre più crescente sia in campo ambientale sia in campo agro-forestale in quanto consentono un’acquisizione rapida e affidabile di nuvole di punti 3D in grado di rappresentare tridimensionalmente gli oggetti rilevati. In un lasso di tempo relativamente breve, tali tecniche hanno aperto la strada ad un ampio spettro di applicazioni in pieno campo. Al di là della misura interattiva di nuvole georeferenziate di punti, le tecniche per il rilevamento automatizzato di oggetti, la determinazione delle loro caratteristiche geometriche e l’analisi della risposta del segnale laser rappresentano temi di ricerca prioritari. L’elevata qualità delle nuvole di punti 3D generate dai sistemi di laser scanning insieme alla possibilità di automatizzare le successive post-elaborazioni dei dati hanno esteso il potenziale applicativo dei laser scanner terrestri anche ai settori ambientali e agro-forestali. Questo contributo illustra innanzitutto lo stato dell’arte dei sistemi laser scanner terrestri dal punto di vista tecnologico e discute le diverse soluzioni tecnologiche e i diversi parametri di sistema in relazione alle possibili applicazioni in campo ambientale e forestale. Nella seconda parte saranno invece presentati alcuni casi di studio esplicativi delle potenzialità e delle limitazioni operative della tecnica di laser scanning terrestre in campo ambientale e agro-forestale.Terrestrial laser scanning techniques find rapidly growing interest in both environmental and agro-forestry fields as efficient tools for fast and reliable 3D point data acquisition and 3D representation of the object viewed by the scanners. They have opened a wide range of application fields within a rather short period of time. Beyond interactive measurement in 3D point clouds, techniques for the automatic detection of objects, the determination of geometric parameters, and the analysis of the reflectance signal form high priority research issues. The high quality of 3D point clouds generated by laser scanners and the data process automation potential make terrestrial laser scanning also an interesting tool for environmental and agro-forestry applications. The paper will first review current laser scanner systems from a technological point of view and discuss different scanner technologies and system parameters regarding their suitability for environmental and agro-forestry applications. In the second part of the paper, results of case studies on potentials and limitations of terrestrial laser scanners in environmental and agro-forestry fields will be presented
Ricostruzione dei flussi di CO2di un ecosistema a macchia mediterranea mediante reti neurali
No full textNell’ultimo decennio sono state realizzate numerose reti di monitoraggio dei flussi di massa ed energia
a scala regionale, che utilizzano come standard di misura la tecnica dell’Eddy Covariance. La continuità del
monitoraggio dei flussi è una condizione difficilmente realizzabile a causa sia della complessità degli apparati di misura
sia di alcune limitazioni di carattere modellistico: in generale dopo i controlli di congruità fisica e biologica, non più del
65% dei dati risulta utilizzabile per la costruzione dei bilanci annuali. Negli ultimi anni sono state sviluppate
metodologie per la ricostruzione dei dati mancanti dei flussi di energia e materia negli ecosistemi terrestri; tuttavia,
attualmente non esiste una metodologia di ricostruzione standardizzata. In questo lavoro vengono realizzati modelli
basati sulle reti neurali per la ricostruzione dei flussi di CO2in un ecosistema a macchia mediterranea; le prestazioni
fornite da tali modelli vengono confrontate con quelle di altre tecniche recentemente proposte dalla comunità
internazionale. I dati sono stati raccolti nel corso del biennio 1998-99 in un sito sperimentale del progetto europeo
MEDEFLU situato nella Sardegna nord-occidentale. I modelli basati sulle reti neurali hanno fornito in genere
prestazioni superiori rispetto agli altri metodi, con valori dell’errore quadratico medio compresi tra 0.9 e 2.9 μmol m-2 s-
1 di CO2. Questi risultati confermano le possibilità applicative delle reti neurali nella ricostruzione dei flussi provenienti
da reti di monitoraggio
A web-based wildfire simulator for operational applications
No full textWildfire simulators and decision support systems can assist the incident command teams in charge of tactical wildfire suppression. This paper presents a web-based wildfire simulator developed to provide real-time support for wildfire management. The paper describes the overall software architecture, the modelling chain characteristics and the results produced by the simulator considering a set of actual wildfires that occurred in the island of Sardinia, Italy. The simulator consists of a graphical user interface that deals with data input-output management, a mass-consistent model devoted to the downscaling of wind fields, and a module that provides a spatially explicit representation of wildfire propagation. The simulator is a client'server application that is operated through a web-based graphical user interface that leaves the computational work to a dedicated server; most of the code is parallelised in order to minimise computational run-time. The validation phase demonstrated the capabilities of the simulator in providing wildfire predictions with a substantial agreement with actual wildfires, and a computational cost suitable for faster than real-time applications. The simulator is proposed as a tool to provide assistance to civil protection and fire management agencies during the incident response phase. The simulator is also appropriate for the training of personnel
Assessing the performance of fire danger indexes in a mediterranean area
No full textThe fire danger (FD) defines the conditions less or more favourable for a fire ignition success and its propagation. FD indexes, that integrates environmental variables related to FD in more or less complex equations and systems, are widely used in wildfire prone countries for both scientific and operational purposes. Assessing the performance of FD indexes is challenging and this issue is quite debated within the fire community, which has been trying to apply several methodologies to evaluate FD indexes. The main aim of this work is to give a contribution to this effort. The analysis was conducted using data from a fire-prone Mediterranean area (Sardinia island, Italy), where 8 FD indexes were evaluated and compared using different statistical approaches. We calculated the daily FD values for the period 2000-2007 over the study area. A set of statistical tools (namely Spearman rank correlation, Index Value Distribution and Percentile Analysis, and Logistic Regression) were applied to evaluate the performance of each FD index by comparing FD values with fire occurrence indicators. The statistical tests revealed a large variability in FD indexes performance, depending also on fire activity conditions. Our results showed that two of the tested FD indexes reached a good overall performance. Findings from this study can help both the scientific community and local fire managers, supporting the evaluation of early warning systems and fire prevention strategies in the Mediterranean Basin
Analysis of phenological behaviour of some mediterranean Shrub species in responses to warming and drought conditions
No full textA phenological behavior of Mediterranean species growing in a Mediterranean-type climate was described by developing a phenological scale. The sensitivity of some Mediterranean species to climate manipulations was evaluated. Climate manipulations were conducted on a Mediterranean macchia ecosystem that include sclerophyll species. The increase of daily minimum temperature of air and soil observed at 20 cm height and at 10 cm depth in the warming treatment was approximately equal to 0.5°C relative to control
An Automatic Algorithm for Mapping Burned Areas from Sentinel Data in Mediterranean Europe: Analysis of 2021 Major Fire Events in Italy and Greece
No full textThe 2021 European summer season has been one of the most intense for Mediterranean regions that experienced a heatwave in August, determining the onset of several fire events across regions in southern Europe [...
An automated approach for wood-leaf separation from terrestrial LIDAR point clouds using the density based clustering algorithm DBSCAN
No full textThe terrestrial light detection and ranging (LiDAR) technique has been recently used to provide 3D structural information of forest canopy at the individual tree level. However, the operational use of Terrestrial Laser Scanner (TLS) for canopy characterization of broadleaf non-deciduous forests needs further investigations. The estimation of wood volume, above-ground woody biomass, tree canopy characteristics and leaf area index often requires separation of photosynthetically active material and non-photosynthetically active material. This article describes an automated wood-leaves separation method, based on spatial geometric information of TLS point clouds, for broad leaved non-deciduous trees. Scans of seven individuals of Quercus suber L. trees were acquired by using the TLS phase-based Leica HDS6100. Point clouds were partitioned in cubic volumes (voxels) that were used as input to generate clusters through the point density algorithm DBSCAN. The clustering process led to the identification of wood and non-wood voxels. A specific automatic routine was written to process data from the point clouds to the visualization of clustering results. The analysis of results showed good performance for this approach, with the overall accuracy in classifying wood components of trees ranging from 95% to 97%. The largest accuracies were observed for branches larger than 5 cm in diameter whereas the accuracy of classification dropped, as expected, for branches with diameter lower than 3 cm. The results suggest that the proposed method can be conveniently used to extract woody components from point clouds of broad leaved non-deciduous trees
Seasonal weather forecasting and models for cultural prediction of yield of wheat in Emilia-Romagna
No full textDevelopment of equal empirical estimates and forecasts for level piezometers using data in the existing problems and precipitation
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