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Saballos, Armando
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Saballos, Armando
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- PublicationOpen AccessSynoptic analysis of a decade of daily measurements of SO2 emission in the troposphere from volcanoes of the global ground-based Network for Observation of Volcanic and Atmospheric Change(2021)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ; ; ; ; ; ; ; ; ; ;; ; ; ;; Volcanic plumes are common and far-reaching manifestations of volcanic activity during and be-tween eruptions. Observations of the rate of emission and composition of volcanic plumes are essential to rec-ognize and, in some cases, predict the state of volcanic activity. Measurements of the size and location of theplumes are important to assess the impact of the emission from sporadic or localized events to persistent orwidespread processes of climatic and environmental importance. These observations provide information onvolatile budgets on Earth, chemical evolution of magmas, and atmospheric circulation and dynamics. Space-based observations during the last decades have given us a global view of Earth’s volcanic emission, particularlyof sulfur dioxide (SO2). Although none of the satellite missions were intended to be used for measurementof volcanic gas emission, specially adapted algorithms have produced time-averaged global emission budgets.These have confirmed that tropospheric plumes, produced from persistent degassing of weak sources, dominatethe total emission of volcanic SO2. Although space-based observations have provided this global insight intosome aspects of Earth’s volcanism, it still has important limitations. The magnitude and short-term variabilityof lower-atmosphere emissions, historically less accessible from space, remain largely uncertain. Operationalmonitoring of volcanic plumes, at scales relevant for adequate surveillance, has been facilitated through the useof ground-based scanning differential optical absorption spectrometer (ScanDOAS) instruments since the be-ginning of this century, largely due to the coordinated effort of the Network for Observation of Volcanic andAtmospheric Change (NOVAC). In this study, we present a compilation of results of homogenized post-analysisof measurements of SO2flux and plume parameters obtained during the period March 2005 to January 2017of 32 volcanoes in NOVAC. This inventory opens a window into the short-term emission patterns of a diverseset of volcanoes in terms of magma composition, geographical location, magnitude of emission, and style oferuptive activity. We find that passive volcanic degassing is by no means a stationary process in time and thatlarge sub-daily variability is observed in the flux of volcanic gases, which has implications for emission budgetsproduced using short-term, sporadic observations. The use of a standard evaluation method allows for intercom-parison between different volcanoes and between ground- and space-based measurements of the same volcanoes.The emission of several weakly degassing volcanoes, undetected by satellites, is presented for the first time. Wealso compare our results with those reported in the literature, providing ranges of variability in emission notaccessible in the past. The open-access data repository introduced in this article will enable further exploitationof this unique dataset, with a focus on volcanological research, risk assessment, satellite-sensor validation, andimproved quantification of the prevalent tropospheric component of global volcanic emission.405 49 - PublicationOpen AccessTracking Formation of a Lava Lake From Ground and Space: Masaya Volcano (Nicaragua), 2014-2017(2018-02)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ;; ; ; ;; ; ;; ;; A vigorously degassing lava lake appeared inside the Santiago pit crater of Masaya volcano (Nicaragua) in December 2015, after years of degassing with no (or minor) incandescence. Here we present an unprecedented-long (3 years) and continuous volcanic gas record that instrumentally characterizes the (re)activation of the lava lake. Our results show that, before appearance of the lake, the volcanic gas plume composition became unusually CO2 rich, as testified by high CO2/SO2 ratios (mean: 12.2 ± 6.3) and low H2O/CO2 ratios (mean: 2.3 ± 1.3). The volcanic CO2 flux also peaked in November 2015 (mean: 81.3 ± 40.6 kg/s; maximum: 247 kg/s). Using results of magma degassing models and budgets, we interpret this elevated CO2 degassing as sourced by degassing of a volatile-rich fast-overturning (3.6–5.2 m3 s−1) magma, supplying CO2-rich gas bubbles from minimum equivalent depths of 0.36–1.4 km. We propose this elevated gas bubble supply destabilized the shallow (<1 km) Masaya magma reservoir, leading to upward migration of vesicular (buoyant) resident magma, and ultimately to (re)formation of the lava lake. At onset of lava lake activity on 11 December 2015 (constrained by satellite-based MODIS thermal observations), the gas emissions transitioned to more SO2-rich composition, and the SO2 flux increased by a factor ∼40% (11.4 ± 5.2 kg/s) relative to background degassing (8.0 kg/s), confirming faster than normal (4.4 versus ∼3 m3 s−1) shallow magma convection. Based on thermal energy records, we estimate that only ∼0.8 of the 4.4 m3 s−1 of magma actually reached the surface to manifest into a convecting lava lake, suggesting inefficient transport of magma in the near-surface plumbing system.634 34 - PublicationOpen AccessHalogen activation in the plume of Masaya volcano: field observations and box model investigations(2021-03-04)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; Volcanic emissions are a source of halogens in the atmosphere. Rapid reactions convert the initially emitted hydrogen halides (HCl, HBr, and HI) into reactive species such as BrO, Br2, BrCl, ClO, OClO, and IO. The activation reaction mechanisms in the plume consume ozone (O3), which is entrained by ambient air that is mixed into the plume. In this study, we present observations of the oxidation of bromine, chlorine, and iodine during the first 11 min following emission, examining the plume from Santiago crater of the Masaya volcano in Nicaragua. Two field campaigns were conducted: one in July 2016 and one in September 2016. The sum of the reactive species of each halogen was determined by gas diffusion denuder sampling followed by gas chromatography–mass spectrometry (GC-MS) analysis, whereas the total halogens and sulfur concentrations were obtained by alkaline trap sampling with subsequent ion chromatography (IC) and inductively coupled plasma mass spectrometry (ICP-MS) measurements. Both ground and airborne sampling with an unoccupied aerial vehicle (carrying a denuder sampler in combination with an electrochemical SO2 sensor) were conducted at varying distances from the crater rim. The in situ measurements were accompanied by remote sensing observations (differential optical absorption spectroscopy; DOAS). The reactive fraction of bromine increased from 0.20 ± 0.13 at the crater rim to 0.76 ± 0.26 at 2.8 km downwind, whereas chlorine showed an increase in the reactive fraction from (2.7 ± 0.7) × 10−4 to (11 ± 3) × 10−4 in the first 750 m. Additionally, a reactive iodine fraction of 0.3 at the crater rim and 0.9 at 2.8 km downwind was measured. No significant change in BrO / SO2 molar ratios was observed with the estimated age of the observed plume ranging from 1.4 to 11.1 min. This study presents a large complementary data set of different halogen compounds at Masaya volcano that allowed for the quantification of reactive bromine in the plume of Masaya volcano at different plume ages. With the observed field data, a chemistry box model (Chemistry As A Boxmodel Application Module Efficiently Calculating the Chemistry of the Atmosphere; CAABA/MECCA) allowed us to reproduce the observed trend in the ratio of the reactive bromine to total bromine ratio. An observed contribution of BrO to the reactive bromine fraction of about 10 % was reproduced in the first few minutes of the model run.175 21