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Clerbaux, C.
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Clerbaux, C.
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- PublicationOpen AccessVolcanic SO2 fluxes derived from satellite data: a survey using OMI, GOME-2, IASI and MODIS(2013)
; ; ; ; ; ; ; ; ; ; ; ; ; ;Theys, N.; Belgian Institute for Space Aeronomy ;Campion, R.; Université Libre de Bruxelles ;Clarisse, L.; Université Libre de Bruxelles ;van Gent, J.; Belgian Institute for Space Aeronomy ;Dils, B.; Belgian Institute for Space Aeronomy ;Corradini, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Merucci, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Coheur, P. F.; Université Libre de Bruxelles ;Van Roozendael, M.; Belgian Institute for Space Aeronomy ;Hurtmans, D.; Université Libre de Bruxelles ;Clerbaux, C.; Univ. Paris ;Tait, S.; Institut de Physique du Globe de Paris ;Ferrucci, F.; Institut de Physique du Globe de Paris; ; ; ; ; ; ; ; ; ; ; ; Sulphur dioxide (SO2)fluxes of active degassing volcanoes are routinely measured with ground-based equipment to characterize and monitor volcanic activity. SO2 of unmonitored volcanoes or from explosive volcanic eruptions, can be measured with satellites. However, remote-sensing methods based on absorption spectroscopy generally provide integrated amounts of already dispersed plumes of SO2 and satellite derived flux estimates are rarely reported. Here we review a number of different techniques to derive volcanic SO2 fluxes using satellite measurements of plumes of SO2 and investigate the temporal evolution of the total emissions of SO2 for three very different volcanic events in 2011: Puyehue-Cord on Caulle (Chile), Nyamulagira (DR Congo) and Nabro (Eritrea). High spectral resolution satellite instruments operating both in the ultravioletvisible (OMI/Aura and GOME-2/MetOp-A) and thermal infrared (IASI/MetOp-A) spectral ranges, and multispectral satellite instruments operating in the thermal infrared (MODIS/Terra-Aqua) are used. We show that satellite data can provide fluxes with a sampling of a day or less (few hours in the best case). Generally the flux results from the different methods are consistent, and we discuss the advantages and weaknesses of each technique. Although the primary objective of this study is the calculation of SO2 fluxes, it also enables us to assess the consistency of the SO2 products from the different sensors used.448 4858 - PublicationRestrictedMeasuring volcanic degassing of SO2 in the lower troposphere with ASTER band ratios(2010)
; ; ; ; ; ; ; ; ; ; ;Campion, R.; Université Libre de Bruxelles, Département des Sciences de la Terre et de l'Environnement. ;Salerno, G. G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Coheur, P. F.; Université Libre de Bruxelles, Chimie Quantique et Photophysique, ;Hurtmans, D.; Université Libre de Bruxelles, Chimie Quantique et Photophysique ;Clarisse, L.; Université Libre de Bruxelles, Chimie Quantique et Photophysique ;Kazahaya, K.; Geological Survey of Japan, Institute of Advanced Science and Technology, ;Burton, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Caltabiano, T.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Clerbaux, C.; Université Libre de Bruxelles, Chimie Quantique et Photophysique, ;Bernard, A.; Université Libre de Bruxelles, Département des Sciences de la Terre et de l'Environnement.; ; ; ; ; ; ; ; ; We present a new method for measuring SO2 with the data from the ASTER (Advanced Spaceborne Thermal Emission and Reflectance radiometer) orbital sensor. The method consists of adjusting the SO2 column amount until the ratios of radiance simulated on several ASTER bands match the observations. We present a sensitivity analysis for this method, and two case studies. The sensitivity analysis shows that the selected band ratios depend much less on atmospheric humidity, sulfate aerosols, surface altitude and emissivity than the raw radiances. Measurements with b25% relative precision are achieved, but only when the thermal contrast between the plume and the underlying surface is higher than 10 K. For the case studies we focused on Miyakejima and Etna, two volcanoes where SO2 is measured regularly by COSPEC or scanning DOAS. The SO2 fluxes computed from a series of ten images of Miyakejima over the period 2000–2002 is in agreement with the long term trend of measurement for this volcano. On Etna, we compared SO2 column amounts measured by ASTER with those acquired simultaneously by ground-based automated scanning DOAS. The column amounts compare quite well, providing a more rigorous validation of the method. The SO2 maps retrieved with ASTER can provide quantitative insights into the 2D structure of non-eruptive volcanic plumes, their dispersion and their progressive depletion in SO2.185 28