A miniaturised ultraviolet spectrometer for remote sensing of SO2 fluxes: a new tool for volcano surveillance

Phil. Trans. R. Soc. A.

2005

Self Cite

ReuseUnless indicated otherwise, fulltext items are protected by copyright with all rights reserved. The copyright exception in section 29 of the Copyright, Designs and Patents Act 1988 allows the making of a single copy solely for the purpose of non-commercial research or private study within the limits of fair dealing. The publisher or other rights-holder may allow further reproduction and re-use of this version -refer to the White Rose Research Online record for this item. Where records identify the publisher as the copyright holder, users can verify any specific terms of use on the publisher's website. TakedownIf you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing eprints@whiterose.ac.uk including the URL of the record and the reason for the withdrawal request. The chemical compositions and emission rates of volcanic gases carry important information about underground magmatic and hydrothermal conditions, with application in eruption forecasting. Volcanic plumes are also studied because of their impacts upon the atmosphere, climate and human health. Remote sensing techniques are being increasingly used in this field because they provide real-time data and can be applied at safe distances from the target, even throughout violent eruptive episodes. However, notwithstanding the many scientific insights into volcanic behaviour already achieved with these approaches, technological limitations have placed firm restrictions upon the utility of the acquired data. For instance, volcanic SO 2 emission rate measurements are typically inaccurate (errors can be greater than 100%) and have poor time resolution (ca once per week). Volcanic gas geochemistry is currently being revolutionized by the recent implementation of a new generation of remote sensing tools, which are overcoming the above limitations and are providing degassing data of unprecedented quality. In this article, I review this field at this exciting point of transition, covering the techniques used and the insights thereby obtained, and I speculate upon the breakthroughs that are now tantalizingly close.

Section: (B ) Ultraviolet Spectroscopymentioning

confidence: 99%

Volcano remote sensing with ground-based spectroscopy

Phil. Trans. R. Soc. A.

2005

Self Cite

“…Because of its abundance in volcanic plumes, low ambient concentrations and highly structured absorption features from 260-340 nm [Manatt and Lane, 1993] SO 2 is also well suited for volcano plume remote sensing . During the last thirty years many studies have been conducted with correlation spectrometers [Stoiber et al, 1983], and more recently compact charge coupled device (CCD) detector based instruments [McGonigle et al, 2002[McGonigle et al, , 2004Galle et al, 2003], to monitor remotely volcanic SO 2 fluxes for purposes of eruption prediction, and to investigate the environmental and atmospheric impacts of these emissions.…”

Section: Introductionmentioning

confidence: 99%

SO₂ depletion in tropospheric volcanic plumes

Geophysical Research Letters

Delmelle

Oppenheimer

et al. 2004

[1] Ground based remote sensing techniques are used to measure volcanic SO 2 fluxes in efforts to characterise volcanic activity. As these measurements are made several km from source there is the potential for in-plume chemical transformation of SO 2 to sulphate aerosol (conversion rates are dependent on meteorological conditions), complicating interpretation of observed SO 2 flux trends. In contrast to anthropogenic plumes, SO 2 lifetimes are poorly constrained for tropospheric volcanic plumes, where the few previous loss rate estimates vary widely (from (1 to >99% per hour). We report experiments conducted on the boundary layer plume of Masaya volcano, Nicaragua during the dry season. We found that SO 2 fluxes showed negligible variation with plume age or diurnal variations in temperature, relative humidity and insolation, providing confirmation that remote SO 2 flux measurements (typically of %500-2000 s old plumes) are reliable proxies for source emissions for ash free tropospheric plumes not emitted into cloud or fog.

“…5. This provides confidence in the inter calibration of both approaches, hence the scope of the UV camera to succeed spectrometer based SO 2 flux observations (e.g., McGonigle et al, 2002;Galle et al, 2003), under appropriate circumstances. Further work now remains in advancing the efforts of Kern et al (2009) in considering the exact under or overestimations incurred in both the spectroscopic and camera based SO 2 retrievals, caused by in-plume and between plume and observer UV scattering.…”

Section: Measurementmentioning

confidence: 72%

Protocols for UV camera volcanic SO2 measurements

Kantzas

Journal of Volcanology and Geothermal Research

Tamburello

et al. 2010

Ultraviolet camera technology offers considerable promise for enabling 1 Hz timescale acquisitions of volcanic degassing phenomena, providing two orders of magnitude improvements on sampling frequencies from conventionally applied scanning spectrometer systems. This could, for instance enable unprecedented insights into rapid processes, such as strombolian explosions, and non-aliased corroboration with volcano geophysical data. The uptake of this technology has involved disparate methodological approaches, hitherto. As a means of expediting the further proliferation of such systems, we here study these diverse protocols, with the aim of suggesting those we consider optimal. In particular we cover: choice and set up of hardware, calibration for vignetting and for absolute concentrations using quartz SO 2 cells, the retrieval algorithm and whether one or two filters, or indeed cameras, are necessary. This work also involves direct intercomparisons with narrowband observations obtained with a scanning spectrometer system, employing a differential optical absorption spectroscopic evaluation routine, as a means of methodological validation.