1,720,962 research outputs found
Utilizzo di immagini satellitari nella gestione post evento degli incendi boschivi
Full text linkL’area Mediterranea è sistematicamente colpita da incendi che danneggiano vaste aree vegetate. Gli incendi boschivi hanno un impatto rilevante sugli ecosistemi e possono causare fenomeni di erosione del terreno, instabilità dei pendii, tendenza alla desertificazione. L’impatto interessa anche l’ambito economico colpito dall’inevitabile diminuzione del turismo.
Ogni anno, in alcune aree del Mediterraneo, come l’Italia, la Francia, il Portogallo, la Spagna e la Grecia, centinaia di migliaia di ettari di foreste sono vittima degli incendi [1]: circa 65000 incendi bruciano approssimativamente 500000 ettari di aree vegetate. Negli ultimi 30 anni, nonostante le nuove tecniche antincendio, le diverse strategie per il contenimento e la tecnologia per l’informazione e la comunicazione, lo scenario non è cambiato. Per apportare miglioramenti nell’informazione e prevenire gli incendi boschivi, è necessario valorizzare l’uso di prodotti derivanti da misure satellitari, i sistemi di rivelazione degli incendi mediante osservazione da terra e dallo spazio ed è necessario migliorare la stima degli effetti dell’incendio sulla vegetazione per stabilire la priorità per gli interventi di ripristino.
Lo scopo del progetto europeo PREFER (Space-based Information Support for Prevention and REcovery of Forest Fires Emergency in the MediteRranean Area) è generare prodotti a supporto delle attività di prevenzione incendi e la fase di recupero e ricostruzione [2], [3].
Il lavoro, svolto grazie al coinvolgimento in questo progetto Europeo, riguarda lo sviluppo di una metodologia per la generazione di mappe di severità del danno da incendio sulla vegetazione (fire damage severity maps) che rientra nell’attività di recupero e ricostruzione. Le mappe vengono ottenute mediante un algoritmo automatico che, utilizzando immagini Landsat 8 ad alta risoluzione spaziale ( 30 m) e bassa risoluzione temporale (16 giorni), calcola gli indici differential Normalized Burn Ratio (DNBR), Burn Severity Index (BSI) e Damage Severity Index (DSI) [4]. Con le soglie del danno per l’indice DSI si ottengono le soglie per gli altri indici e vengono così generate tre mappe del livello di danno per ogni area bruciata.
I risultati ottenuti sono validati con immagini RapidEye ad altissima risoluzione spaziale ( 5 m) prima e dopo l’evento e con foto acquisite in situ.
Viene studiata inoltre l’influenza dell’atmosfera e degli aerosol sulla stima del livello del danno
Detection of volcanic gases and particles by satellite
No full textIn this paper the detection of components of volcanic eruption has been carried out investigating, in appropriate bands of the electromagnetic spectrum (6.25, 8.7, 10.8, 12 μm), the values of the brightness temperature. The analysis has been performed in the Thermal Infrared Region (TIR) studying both the absorption-emission and scattering phenomena related to the interactions between electromagnetic radiation and volcanic emissions. The results have been achieved by means of a combined use of numerical simulations, devoted to examining the behaviour of the atmosphere gases and volcanic components, and remotely sensed satellite images. The proposed methodologies allow an estimate of the amount of gaseous and solid components, of the size of the emitted particles, of the height of the volcanic plume and of the distance of the volcanic components from the crater. The processed images come from the Spinning Enhanced Visible and InfraRed Imager (SEVIRI) sensor on board the geo-stationary satellite Meteosat Second Generation (MSG) and take into consideration an eruption of the Etna volcano as a study case (1st of April 2012, 04:30 and 05:30 UTC). The procedures are general and may therefore be extended to any other similar case. © 2013 IAA
Achievements of the prefer project in the prevention phase of the forest fire management
No full textThe three years FP7 project PREFER (Space-based information support for the Prevention and Recovery of Forest Fires Emergency in the Mediterranean Area) devoted to develop a satellite based service infrastructure capable to provide up-to-date information to support the preparedness, prevention, recovery and reconstruction phases of the Forest Fires emergency cycle in the European Mediterranean Region, has been successfully completed at the end of 2015. However, the project consortium will make available its products for the 2016 summer season, too. The present paper aims at presenting the project achievements emphasizing the most innovative information products developed in the framework of the project. For such products the methodology, validation and demonstration results will be presented and discussed
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
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
development and validation of fire damage-severity indices in the framework of the PREFER project
No full textPREFER (space-based information support for prevention and recovery of forest fires emergency in the Mediterranean area) is one of the Copernicus FP7 Emergency projects funded in 2012. It is uniquely devoted to forest pre- and post-fire management. The overall goal of the project is to develop and demonstrate a preoperational portfolio of products, based on Earth observation data for helping fire management on a Mediterranean scale. Samples of the PREFER information products are available to stakeholders through the project Geoserver (prefer.cgspace.it). The project foresees the utilization of satellite images' optical and SAR at medium (MODIS-moderate resolution imaging spectroradiometer), high (Landsat, Spot-Satellite Pour l'Observation de la Terre), and very high (KOMPSAT-Korea Multi-Purpose Satellite, RapidEye, Pleiades, COSMO-SkyMed-constellation of small satellites for Mediterranean basin observation, and TanDEM-X-TerraSAR-X add on for digital elevation measurement) spatial resolution, and a refresh rate of the products varying from high (days) to low (twice a month) to very low (once a year). The present paper is devoted to introducing the methodology developed for computing one of the project product, i.e., the damage-severity map. These maps provide the level of damage caused in vegetated areas by fires. Further, the paper aims at presenting the results of the validation of such product carried out during the first semester of 2015. The methodology is based on the utilization of Landsat8/OLI images
The PREFER FP7 project: damage severity maps validation results
No full textPREFER is one of the Copernicus FP7 Emergency projects funded in 2012. It is uniquely devoted to forest pre-and post-fire management. The overall goal of the project is to develop and demonstrate a pre-operational portfolio of products, based on Earth Observation data for helping fires management at Mediterranean scale. Samples of the PREFER (Space-based Information Support for Prevention and REcovery of Forest Fires Emergency in the MediteRranean Area) information products are available to stakeholders through the project Geoserver (prefer.cgspace.it). The project foresees the utilization of satellite images optical and SAR at low (MODIS), medium (Landsat, Spot) and high (Kompsat, RapidEye, Pleiades, Cosmo-SkyMed, TanDEM-X, etc.) spatial resolution and a refresh rate of the products varying from high (days) to low (twice a month) to very low (once a year). The present paper is devoted to introduce the methodology developed for computing the maps of the level of damage caused in vegetated areas by fires and to present the results of the validation process just starte
Monitoring volcanic ash by using geostationary satellite
No full textVolcanic hazards are of major national and international importance, affecting many regions of the globe and potentially having an impact on people both on the ground and in transit in the air. The authors of this paper have been involved as part team in the GMES FP7 `Downstream' Service project called EVOSS (European Volcano Observatory Space Services) aiming at developing a portfolio of services for supporting the volcanic hazard monitoring. In the framework of this project a study of the possibility of detecting the components of volcanic eruption has been carried out investigating, in appropriate bands of the electromagnetic spectrum (6.25, 8.7, 10.8, 12 μm), the values of the brightness temperature. The results have been achieved by means of a combined use of numerical simulations, devoted to examining the behavior of the atmosphere gases and volcanic components, and remotely sensed satellite images. The processed images come from the SEVIRI (Spinning Enhanced Visible and InfraRed Imager) sensor on board the geo-stationary satellite Meteosat Second Generation (MSG). When the monitoring system was tested by using real-time data from MSG it became clear the need of improving the cloud mask algorithm in order to minimize the false alarms. This paper describes the technique followed to minimize the impact of clouds on the detection of ash plume. The priority was given to the reduction of false alarms, that is: confuse meteorological clouds with ash and provide plume extension much larger than the actual siz
- …
