An application of tomographic reconstruction of atmospheric CO/sub 2/ over a volcanic site based on open-path ir laser measurements

Belotti, Claudio; Cuccoli, Fabrizio; Facheris, Luca; Vaselli, Orlando

doi:10.1109/tgrs.2003.815400

Cited by 20 publications

(12 citation statements)

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“…Instantaneous CO 2 concentration in air was measured along predefined optical paths by a differential spectroscopy absorption (DSA) instrument (Belotti et al 2003) consisting of an IR portable diode laser system operating at 1,580 nm (Cuccoli et al 2000) and passive retro-reflectors (Fig. 2).…”

Section: Methodsmentioning

confidence: 99%

A Geochemical Multi-Methodological Approach in Hazard Assessment of CO2-Rich Gas Emissions at Mt. Amiata Volcano (Tuscany, Central Italy)

Tassi

Vaselli

Cuccoli³

et al. 2008

Water Air Soil Pollut: Focus

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The present work aims to assess the hazard for human health related to CO 2 anomalous concentrations in air emitted from dry gas vents located in the NE area of Mt. Amiata volcano (Tuscany, central Italy). A geochemical multi-methodological approach is adopted to determine the composition and the flux rate of the gas discharges in order to establish (1) the origin of the gas vents and (2) the behaviour of the discharged gases in the areas surrounding the emission sites. The gas vents are hosted within subcircular morphological depressions (∅∼10-30 m), which likely originated by the collapse of cavities formed at shallow depth in the ground by dissolution of Triassic anhydrite formations and recent travertine deposits. CaCO 3 and CaSO 4 dissolution is mainly related to the underground circulation of CO 2 -rich fluids whose hydrological pattern is regulated by local and regional tectonics. The CO 2 -rich (up to 996,070 μmol/mol) gases tend to accumulate within the topographic lows, thus creating a sort of CO 2 ponds, and the knowledge of their evolution in time and space is important to evaluate the related hazard. Consequently, a conceptual model of CO 2 diffusion in air is developed to understand the dynamic of the CO 2 accumulation/dispersion process based on (1) a 24-h continuous measurement of the CO 2 flux from one of the main emission sites and (2) the recording of the main meteoric parameters, i.e. air temperature, wind direction and speed to check their influence. The results indicate that the threshold of CO 2 concentrations considered dangerous for the human health is frequently overcome. Moreover, when meteoric conditions, i.e. low wind and cloudy weather, did not allow a rapid dispersion of the gas phase emitted from the dry vents, CO 2 -rich clouds periodically overflowed the morphological depressions for several tens of meters without any significant mixing with air. On the basis of these considerations, the monitoring of the output rate from the main gas emissions, combined with the continuous control of the local meteorological parameters, may be considered an efficient procedure to mitigate the CO 2 hazard deriving from dry gas vents. An improvement of the protocol can be achieved in case of installations of CO 2 sensors located in the most sensitive areas and Water Air Soil Pollut: Focus (

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Section: Methodsmentioning

confidence: 99%

A Geochemical Multi-Methodological Approach in Hazard Assessment of CO2-Rich Gas Emissions at Mt. Amiata Volcano (Tuscany, Central Italy)

Tassi

Vaselli

Cuccoli³

et al. 2008

Water Air Soil Pollut: Focus

Self Cite

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“…While the latter is a rather complex task and is examined in the following, the first can be easily solved adopting a suitable network of infrared optical laser links and tomographic processing, as discussed in [8] and [9] and applied in [11]. IR laser systems nowadays available based on transmit/receive units and passive retroreflectors can provide integrated gas measurements along rectilinear paths up to 1 km length in real time on a continuous basis [5]- [7].…”

Section: Flux Estimation Conceptmentioning

confidence: 99%

“…Tomographic processing is typically applied with the main purpose of retrieving the distribution of concentration, for instance, in order to locate the concentration maxima, while in the context of this paper, it is exploited only to provide average gas concentrations over a plane. Though such averages could be estimated directly by means of weighted sums of the linear concentrations measured along the laser links, the tomographic procedure is preferable because of its ability of individuating the concentration maxima also in zones that are not crossed by the links of the measurement network (see the tomographic result in [11] or the Rousseau index applied to the results in [8]). Therefore, the tomographic estimate of the average concentration is expected to be more accurate especially when the measurement network resolution is scarce, as in one of the two cases discussed in this paper.…”

Section: Flux Estimation Conceptmentioning

confidence: 99%

“…They are small, compact and require small amount of power. Depending on the arrangement of the optical links, 2-D and 3-D concentration fields of the monitored gas can be reconstructed in the air volume close to the emission area by means of specific tomographic data-processing algorithms [8]- [11]. During the last five years, many field campaigns using an infrared laser system for CO 2 measurement in air were carried out in several locations (volcanic, geothermal, industrial, and waste disposal sites) [12], [13].…”

Section: Introductionmentioning

confidence: 99%

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Volumetric IR Laser Monitoring for the Estimation of the Gas Emission Flux by Surface Sources: Method and Simulation Results

Cuccoli

Facheris

2011

IEEE Trans. Geosci. Remote Sensing

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A measurement approach is presented for estimating the gas emission flux by a surface source based on the use of infrared laser measurements along optical links. An ad hoc arrangement optical links surrounding the emission area allows one to measure gas concentration over a close surface corresponding to an air volume that covers the whole emission area. We show some simulation results of surface flux measurements assuming that the concentration measurements are made over five faces of a parallelepiped, while the sixth (bottom) face is the emission surface. We discuss some estimation results based on a stationary diffusion model applied to point sources where the air diffusion and transportation phenomena are due mainly to the horizontal wind.

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“…It has, for example, become possible to resolve features in nonuniform flow fields from one, or at most two, distinct absorption features. [2][3][4][5][6][7] To permit successful tomographic reconstructions, line-of-sight measurements must be performed along multiple directions using either parallel or fanned beam arrangements, both require mechanical means for angular beam displacement and thus spatial resolution is obtained at the cost of reduced temporal resolution. This is a problem for application in fast-changing turbulent flames.…”

mentioning

confidence: 99%

A tomographic technique for the simultaneous imaging of temperature, chemical species, and pressure in reactive flows using absorption spectroscopy with frequency-agile lasers

Kaminski

2014

Applied Physics Letters

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This paper proposes a technique that can simultaneously retrieve distributions of temperature, concentration of chemical species, and pressure based on broad bandwidth, frequency-agile tomographic absorption spectroscopy. The technique holds particular promise for the study of dynamic combusting flows. A proof-of-concept numerical demonstration is presented, using representative phantoms to model conditions typically prevailing in near-atmospheric or high pressure flames. The simulations reveal both the feasibility of the proposed technique and its robustness. Our calculations indicate precisions of ∼70 K at flame temperatures and ∼0.05 bars at high pressure from reconstructions featuring as much as 5% Gaussian noise in the projections.

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An application of tomographic reconstruction of atmospheric CO/sub 2/ over a volcanic site based on open-path ir laser measurements

Cited by 20 publications

References 7 publications

A Geochemical Multi-Methodological Approach in Hazard Assessment of CO2-Rich Gas Emissions at Mt. Amiata Volcano (Tuscany, Central Italy)

A Geochemical Multi-Methodological Approach in Hazard Assessment of CO2-Rich Gas Emissions at Mt. Amiata Volcano (Tuscany, Central Italy)

Volumetric IR Laser Monitoring for the Estimation of the Gas Emission Flux by Surface Sources: Method and Simulation Results

A tomographic technique for the simultaneous imaging of temperature, chemical species, and pressure in reactive flows using absorption spectroscopy with frequency-agile lasers

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