1,721,107 research outputs found
Differential absorption lidar for volcanic CO2 sensing tested in an unstable atmosphere
No full textMotivated by the need for an extremely durable and portable instrument to quantify volcanic CO2 we have produced a corresponding differential absorption lidar (DIAL). It was tested on a volcano (Vulcano, Italy), sensing a non-uniform volcanic CO2 signal under turbulent atmospheric conditions. The measured CO2 mixing ratio trend agrees qualitatively well but quantitatively poorly with a reference CO2 measurement. The disagreement is not in line with the precision of the DIAL determined under conditions that largely exclude atmospheric effects. We show evidence that the disagreement is mainly due to atmospheric turbulence. We conclude that excluding noise associated with atmospheric turbulence, as commonly done in precision analysis of DIAL instruments, may largely underestimate the error of measured CO2 concentrations in turbulent atmospheric conditions. Implications for volcanic CO2 sensing with DIAL are outlined. © 2015 Optical Society of America
Lidar detection of carbon dioxide in volcanic plumes
No full textVolcanic gases give information on magmatic processes. In particular, anomalous releases of carbon dioxide precede volcanic eruptions. Up to now, this gas has been measured in volcanic plumes with conventional measurements that imply the severe risks of local sampling and can last many hours. For these reasons and for the great advantages of laser sensing, the thorough development of volcanic lidar has been undertaken at the Diagnostics and Metrology Laboratory (UTAPRAD-DIM) of the Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA). In fact, lidar profiling allows one to scan remotely volcanic plumes in a fast and continuous way, and with high spatial and temporal resolution. Two differential absorption lidar instruments will be presented in this paper: BILLI (BrIdge voLcanic LIdar), based on injection seeded Nd:YAG laser, double grating dye laser, difference frequency mixing (DFM) and optical parametric amplifier (OPA), and VULLI (VULcamed Lidar), based on injection seeded Nd:YAG laser and optical parametric oscillator (OPO). The first one is funded by the ERC (European Research Council) project BRIDGE and the second one by the ERDF (European Regional Development Fund) project VULCAMED. While VULLI has not yet been tested in a volcanic site, BILLI scanned the gas emitted by Pozzuoli Solfatara (Campi Flegrei volcanic area, Naples, Italy) during a field campaign carried out from 13 to 17 October 2014. Carbon dioxide concentration maps were retrieved remotely in few minutes in the crater area. Lidar measurements were in good agreement with well-established techniques, based on different operating principles. To our knowledge, it is the first time that carbon dioxide in a volcanic plume is retrieved by lidar, representing the first direct measurement of this kind ever performed on an active volcano and showing the high potential of laser remote sensing in geophysical research. © 2015 Copyright SPIE
Spectroscopic considerations on DIAL measurement of carbon dioxide in volcanic emissions
No full textThe true magnitude of CO2 emissions from volcanic activity is poorly constrained, limiting our understanding of the natural carbon cycle. CO2-sensitive lidars could be used to measure the distribution of CO2 in a volcanic plume, thereby allowing volcanic CO2 fluxes to be measured directly. The recently-begun ERC research project CO2VOLC aims to produce such an instrument based on the differential absorption lidar (DIAL) technique. In this paper we investigate the ON and OFF wavelengths which offer optimal CO2 detection and identify the spectral requirements of the lidar transmitter, in the context of commercially available solid-state laser sources
Fast tracking of wind speed with a differential absorption LiDAR system: First results of an experimental campaign at Stromboli volcano
No full textCarbon dioxide (CO2) is considered a precursor gas of volcanic eruptions by volcanologists. Monitoring the anomalous release of this parameter, we can retrieve useful information for the mitigation of volcanic hazards, such as for air traffic security. From a dataset collected during the Stromboli volcano field campaign, an assessment of the wind speed, in both horizontal and vertical paths, performing a fast tracking of this parameter was retrieved. This was determined with a newly designed shot-per-shot differential absorption LiDAR system operated in the near-infrared spectral region due to the simultaneous reconstruction of CO2 concentrations and wind speeds, using the same sample of LiDAR returns. A correlation method was used for the wind speed retrieval in which the transport of the spatial inhomogeneities of the aerosol backscattering coefficient, along the optical path of the system, was analyzed. © 2017 Society of Photo-Optical Instrumentation Engineers (SPIE)
Investigating the effect of aerosol droplets in a volcanic plume for increasing sensitivity of a CO2 DIAL measurement
No full textVolcanic CO2 emissions are an important element of the carbon cycle, but they are very poorly constrained. This is due to the great challenge posed by the quantification of a potentially small volcanic CO2 signal against a strong background atmospheric signal. There is therefore great interest in developing and applying novel, sensitive techniques which may be able to remotely quantify trace volcanic CO2 amounts. Differential Absorption LIDAR (DIAL) is one such technique which may allow remote monitoring of volcanic CO2 emissions. CO2 is typically the second most abundant volcanic gas, the first being H2O, which can condense upon emission, producing dense aerosol clouds. These aerosols will strongly affect absorption and backscattering of the probing DIAL light. We employ Mie's equations to calculate their scattering and extinction properties. We consider two extreme droplet number densities. We find that both backscattering and extinction coefficient increase by more than 4 orders of magnitude with respect to the case without any liquid water in the volcanic plume. The fraction of light scattered back to the DIAL instrument in a single scattering event increases by a factor of 100 relative to the clear atmosphere. For the LIDAR signal this implies a relative increase in backscattered light by up to 4 and 5 orders of magnitude for the low density and high density cloud scenario, respectively. The results suggest that a condensed water cloud within the plume region may act as a strong reflector, and greatly enhances the signal strength and hence sensitivity of a DIAL system compared with backscattering in the clear atmosphere. © 2013 SPIE
Groundwater fluorescence analysis in Southern Italian regions affected by desertification processes
No full textDesertification is the degradation of land in arid, semi-arid, and dry sub-humid areas and it is primarily due to human activities and climatic variations. Nowadays, this matter does not refer only to the expansion of existing deserts but it occurs because dryland ecosystems are extremely vulnerable to climate changes, over-exploitation and inappropriate land use.
In the Italian scenario, the impact of desertification is restricted to the southern regions where the risk is linked to water erosion, strong human aggressiveness, intense precipitations and to water and soil salinization.
To this respect, the Italian project RIADE (Integrated Research for Applying new technologies and processes for combating DEsertification), has selected the area of Syracuse and the alluvial plain of the Licata town for an integrated application of the hydrogeochemical and spectroscopical methods in order to settle on qualitative characteristics of the water resources.
Laser Induced Fluorescence (LIF) spectroscopy has been chosen for its intrinsic skills to be employed in real time water quality parameter determinations, with portable instruments during intensive monitoring campaigns. This technique allows to perform qualitative and quantitative in situ determination of dissolved (humic and fulvic acids, pollutants) or particulate (phytoplankton) organic matter. The ENEA laser remote sensing laboratory has designed and developed a new portable instrument, in order to match the requests of monitoring skills on relevance sites for RIADE.
In the late Spring 2005 (May 22 – 25), a joint campaign has been performed in the Licata area (Sicily, Agrigento province), along the Salso river and in different wells in the neighbourhood territory. Distribution maps of the measured parameters as: a) dissolved matter, i.e. CDOM (Chromophoric Dissolved Organic Matter), tyrosine and tryptophan; b) particulate matter (algae); c) groundwater depth; d) electrical conductivity; e) pH; f): temperature; will be presented and discussed in term of emerging information on ongoing desertification processes
In-situ and stand-off detection of radionuclides by laser spectroscopy. A feasibility study
Full text linkIl Laboratorio Diagnostiche e Metrologia (FSN-TECFIS-DIM) dell’Agenzia Nazionale per le Nuove Tecnologie, l’Energia e lo Sviluppo Economico Sostenibile (ENEA) ha applicato da anni la spettroscopia laser fotoacustica (LPAS) alla sicurezza alimentare (in situ) e il lidar ad assorbimento differenziale (DIAL) alla rilevazione di esplosivi e al monitoraggio ambientale (a distanza). Tenendo conto del recente rinnovato interesse per l’energia nucleare, da un lato, e della perdurante preoccupazione dell’opinione pubblica sulla sicurezza e protezione nucleare, dall’altro, è stato condotto uno studio di fattibilità preliminare sulla rilevazione di iodio mediante LPAS e DIAL. I suoi risultati sono promettenti per lo ioduro di metile, una forma volatile di radioiodio, e aprono la strada allo sviluppo di sensori laser in situ e a distanza per la sicurezza nucleare. Il Laboratorio di Metodi e Tecniche per la Sicurezza Nucleare, il Monitoraggio e la Tracciabilità (FSN-SICNUC-TNMT) applica la spettroscopia gamma per il monitoraggio di radionuclidi mobili nell’ambiente e potrebbe utilizzare le tecniche LPAS e DIAL per supportare la valutazione e lo studio della concentrazione di radionuclidi rilevanti per la sicurezza e protezione nucleareThe Diagnostics and Metrology Laboratory (FSN-TECFIS-DIM) of the Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA) applied for years laser photoacoustic spectroscopy (LPAS) to food safety (in-situ) and differential absorption lidar (DIAL) to explosive detection and environmental monitoring (stand-off). Taking into account the recent renewed interest in nuclear energy, from one hand, and the long-lasting public concern on nuclear safety and security, from the other one, a preliminary feasibility study on iodine detection by LPAS and DIAL has been carried out. Its results are promising for methyl iodide, a volatile form of radioiodine, and pave the way for the development of in-situ and stand-off laser sensors for nuclear security. The Laboratory for Methods and Techniques for Nuclear Security, Traceability and Monitoring (FSN-SICNUC-TNMT) applies gamma spectroscopy for monitoring mobile radionuclides in the environment and could use the LPAS and DIAL techniques to support the evaluation and the study of the concentration of relevant radionuclides for nuclear safety and security
Ecological transition. Economic, environmental and social challenges
Full text linkIn questo tempo di crisi, scopriamo la necessità di valori antropologici per guidare la navigazione della nostra specie su questo pianeta. Dal 2000 EcoOne, sezione ecologica dell’Associazione Internazionale New Humanity-NGO (status consultivo generale dell’ECOSOC delle Nazioni Unite, partner ufficiale dell’UNESCO, accreditata presso l’UNEP) ha organizzato numerose conferenze internazionali su temi ambientali. L’incontro del 2020 “Nuove vie verso l’ecologia integrale” ha discusso le sfide economiche, ambientali e sociali della transizione ecologica: alcuni paper selezionati della conferenza sono pubblicati in questo rapporto.In this time of crisis, we discover the need for anthropological values to guide the navigation of our species on this planet. Since 2000 EcoOne, the ecological section of the International New Humanity Association-NGO (general consultative status of the United Nations ECOSOC, official partner of UNESCO, accredited to UNEP) has organized numerous international conferences on environmental issues. The 2020 meeting “New Pathways to Integral Ecology” discussed the economic, environmental and social challenges of the ecological transition: some selected papers from the conference are published in this report
Compact laser spectrofluorometer for water monitoring campaigns of Southern Italian regions affected by salinization and desertification processes.
No full textA compact laser spectrofluorometer has been developed and employed in the diagnosis of
water quality parameters in the frame of the Italian project Integrated Research for Applying
new technologies and processes for combating DEsertification (RIADE). The instrument has
been designed to be autonomously operated in field campaigns as that conducted in the
groundwater-bearing areas of Licata (Southern Italy), affected by high salinity contents
induced by the Salso river and by coastal seawater intrusion phenomena. Dissolved
(chromophoric dissolved organic matter, tyrosine and tryptophan) and particulate (algae)
matter was monitored during the abovementioned field campaign (May 2005) in different
wells within the countryside around the Licata area. Measurements of that monitoring activity
were therefore compared to: a) the groundwater depth of wells, b) the in situ measurement of
chemical-physical parameters (electrical conductivity, pH and temperature) and c) the
geochemical composition of the groundwater. The results stress the reduction of water retain
due to salt releases in the aquifers. Georeferenced maps of the measured parameters are
presented and discussed
Volcanic CO2 detection with a DFM/OPA-based lidar
No full textThe DFM/OPA-based lidar BILLI was used to investigate the volcanic plume released by the hydrothermal vent of Pisciarelli, in the Campi Flegrei volcano. BILLI remotely measured CO2 concentrations in cross-sections of the nearvent plume using the differential absorption technique. To our knowledge, this is the first example of lidar-based measurement of volcanic CO2 . The spatial resolution was 1.5 m and the temporal resolution 20 s. © 2015 Optical Society of America
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