SO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; and BrO emissions of Masaya volcano from 2014 to 2020

Dinger, Florian; Kleinbek, Timo; Dörner, Steffen; Bobrowski, Nicole; Platt, U.; Wagner, Thomas; Ibarra, Martha; Espinoza, Eveling

doi:10.5194/acp-21-9367-2021

Cited by 10 publications

(6 citation statements)

References 85 publications

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“…Finally, Jourdain et al (2016) focuses on the wider-scale impact of volcanic emissions, whereas this study focuses more on the detailed mechanisms of halogen cycling in the early plume with cross-validation against ozone and halogen radical observations. WRF-Chem has been used in several studies to model tropospheric volcanic plumes, generally showing good agreement with observations (Stuefer et al, 2013;Burton et al, 2020;Egan et al, 2020;Rizza et al, 2020;Hirtl et al, 2019Hirtl et al, , 2020. Such studies have predominantly focused on ash and SO 2 distribution, and there have been none, to our knowledge, that incorporate halogen chemistry.…”

Section: Numerical Modellingmentioning

confidence: 63%

Observation and modelling of ozone-destructive halogen chemistry in a passively degassing volcanic plume

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Roberts²,

Bekki

2021

Atmos. Chem. Phys.

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Abstract. Volcanoes emit halogens into the atmosphere that undergo complex chemical cycling in plumes and cause destruction of ozone. We present a case study of the Mount Etna plume in the summer of 2012, when the volcano was passively degassing, using aircraft observations and numerical simulations with a new 3D model “WRF-Chem Volcano” (WCV), incorporating volcanic emissions and multi-phase halogen chemistry. Measurements of SO2 – an indicator of plume intensity – and ozone were made in the plume a few tens of kilometres from Etna, revealing a strong negative correlation between ozone and SO2 levels. From these observations, using SO2 as a tracer species, we estimate a mean in-plume ozone loss rate of 1.3×10−5 molecules of O3 per second per molecule of SO2. This value is similar to observation-based estimates reported very close to Etna's vents, indicating continual ozone loss in the plume up to at least tens of kilometres downwind. The WCV model is run with nested grids to simulate the plume close to the volcano at 1 km resolution. The focus is on the early evolution of passively degassing plumes aged less than 1 h and up to tens of kilometres downwind. The model is able to reproduce the so-called “bromine explosion”: the daytime conversion of HBr into bromine radicals that continuously cycle in the plume. These forms include the radical BrO, a species whose ratio with SO2 is commonly measured in volcanic plumes as an indicator of halogen ozone-destroying chemistry. The species BrO is produced in the ambient-temperature chemistry, with in-plume BrO / SO2 ratios on the order of 10−4 mol/mol, similar to those observed previously in Etna plumes. Wind speed and time of day are identified as non-linear controls on this ratio. Sensitivity simulations confirm the importance of near-vent radical products from high-temperature chemistry in initiating the ambient-temperature plume halogen cycling. Heterogeneous reactions that activate bromine also activate a small fraction of the emitted chlorine; the resulting production of chlorine radical Cl strongly enhances the methane oxidation and hence the formation of formaldehyde (HCHO) in the plume. Modelled rates of ozone depletion are found to be similar to those derived from aircraft observations. Ozone destruction in the model is controlled by the processes that recycle bromine, with about three-quarters of this recycling occurring via reactions between halogen oxide radicals. Through sensitivity simulations, a relationship between the magnitude of halogen emissions and ozone loss is established. Volcanic halogen cycling profoundly impacts the overall plume chemistry in the model, notably hydrogen oxide radicals (HOx), nitrogen oxides (NOx), sulfur, and mercury chemistry. In the model, it depletes HOx within the plume, increasing the lifetime of SO2 and hence slowing sulfate aerosol formation. Halogen chemistry also promotes the conversion of NOx into nitric acid (HNO3). This, along with the displacement of nitrate out of background aerosols in the plume, results in enhanced HNO3 levels and an almost total depletion of NOx in the plume. The halogen–mercury model scheme is simple but includes newly identified photo-reductions of mercury halides. With this set-up, the mercury oxidation is found to be slow and in near-balance with the photo-reduction of the plume. Overall, the model findings demonstrate that halogen chemistry has to be considered for a complete understanding of sulfur, HOx, reactive nitrogen, and mercury chemistry and of the formation of sulfate particles in volcanic plumes.

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Section: Numerical Modellingmentioning

confidence: 63%

Observation and modelling of ozone-destructive halogen chemistry in a passively degassing volcanic plume

Surl

Roberts²,

Bekki

2021

Atmos. Chem. Phys.

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“…Gas accumulation in the crater has been proposed to account for correlations between wind speed and SO 2 emission rate at Masaya volcano (Dinger et al., 2021), but it seems unlikely that it could account for the common periodicities identified here, owing to the range of volcano types and surface activity. Despite explosive emissions creating poor measurement conditions, SO 2 emission rates used in this study span episodes of both explosive activity and passive degassing (Figure A1).…”

Section: Resultsmentioning

confidence: 84%

“…For measurements conducted under ideal conditions, it is well‐known that plume speeds are the main source of error in SO 2 emission rates (Arellano et al., 2021) and correlations have been observed between SO 2 emission rate and wind speed at several volcanoes (e.g., Dinger et al., 2021). The fact that these correlations translate into periodicities implies a systematic error in the calculation of SO 2 emission rates.…”

Section: Resultsmentioning

confidence: 99%

“…This range in reported periodicities may reflect the behavior and state of the system, but also depends on the instrumental techniques and therefore sampling rate used to study volcanic gases. Periodicities have been observed in time series of diffuse gas emanations of radon (Aumento, 2002;Cigolini et al, 2009) and CO 2 (Viveiros et al, 2015), as well as in the relative concentrations of plume-gas species recorded by electrochemical sensors (Moussallam et al, 2017) and ground-based remote sensing techniques, including Fourier-Transform Infrared (FTIR; Allard et al, 2016) and Differential Optical Absorption Spectroscopy (DOAS; Dinger et al, 2018Dinger et al, , 2021Warnach et al, 2019). The emission rate of SO 2 as a plume-gas is an important parameter for forecasting activity and monitoring ongoing eruptions for the world's most active volcanoes.…”

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confidence: 99%

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Wind Speed as a Dominant Source of Periodicities in Reported Emission Rates of Volcanic SO₂

et al. 2022

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Volcanoes have been found to display periodicities or cyclic trends in a wide range of phenomena. These include the eruptive activity itself, but also in the time series of geophysical and geochemical monitoring data such as volcanic degassing. Here, we test the existence of periodicities of volcanic degassing at 32 volcanoes using the time series of sulfur dioxide (SO2) emission rates from data of the Network of Volcanic and Atmospheric Change (NOVAC). We use the Lomb‐Scargle periodogram to analyze the SO2 data which allows efficient computation of a Fourier‐like power spectrum from unevenly sampled data. We were able to calculate False‐Alarm Probabilities in 28 of the 32 volcanoes, and we identified significant periodicities in the SO2 emission rates in 17 of the 28 volcanoes. However, we find that most of these periodicities are also present in the plume speeds used to determine SO2 emission rates. Periodicities at about 30–70, ∼120, and ∼180 days were identified at volcanoes located between 16°N and 16°S and are related to intraseasonality and interseasonality in global trade winds and not volcanic in origin. Periodicities between 30 and 70 days in both plume speed and SO2 emission rates are associated to the Madden‐Julian Oscillation that is responsible for intraseasonal variability in the tropical atmosphere. Our study highlights the importance of using local wind data for deriving realistic SO2 emissions and the identification of short‐term periodicity in volcanic behavior.

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“…Plume diameters close to volcanic vents are typically ≤ 1 km (see e.g. Bobrowski et al, 2003;Bobrowski and Platt, 2007;Dinger et al, 2021). Thus, we assume as a standard scenario a plume with an extension of 1 × 1 × 1 km 3 .…”

Section: Sizes Of the Volcanic Plumesmentioning

confidence: 99%

Investigation of three-dimensional radiative transfer effects for UV–Vis satellite and ground-based observations of volcanic plumes

et al. 2023

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Abstract. We investigate effects of the three-dimensional (3D) structure of volcanic plumes on the retrieval results of satellite and ground-based UV–Vis observations. For the analysis of such measurements, 1D scenarios are usually assumed (the atmospheric properties only depend on altitude). While 1D assumptions are well suited for the analysis of many atmospheric phenomena, they are usually less appropriate for narrow trace gas plumes. For UV–Vis satellite instruments with large ground pixel sizes like the Global Ozone Monitoring Experiment-2 (GOME-2), the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) or the Ozone Monitoring Instrument (OMI), 3D effects are of minor importance, but usually these observations are not sensitive to small volcanic plumes. In contrast, observations of the TROPOspheric Monitoring Instrument (TROPOMI) on board Sentinel-5P have a much smaller ground pixel size (3.5 × 5.5 km2). Thus, on the one hand, TROPOMI can detect much smaller plumes than previous instruments. On the other hand, 3D effects become more important, because the TROPOMI ground pixel size is smaller than the height of the troposphere and also smaller than horizontal atmospheric photon path lengths in the UV–Vis spectral range. In this study we investigate the following 3D effects using Monte Carlo radiative transfer simulations: (1) the light-mixing effect caused by horizontal photon paths, (2) the saturation effect for strong SO2 absorption, (3) geometric effects related to slant illumination and viewing angles and (4) plume side-effects related to slant illumination angles and photons reaching the sensor from the sides of volcanic plumes. The first two effects especially can lead to a strong and systematic underestimation of the true trace gas content if 1D retrievals are applied (more than 50 % for the light-mixing effect and up to 100 % for the saturation effect). Besides the atmospheric radiative transfer, the saturation effect also affects the spectral retrievals. Geometric effects have a weaker influence on the quantitative analyses but can lead to a spatial smearing of elevated plumes or even to virtual double plumes. Plume side-effects are small for short wavelengths but can become large for longer wavelengths (up to 100 % for slant viewing and illumination angles). For ground-based observations, most of the above-mentioned 3D effects are not important because of the narrow field of view (FOV) and the closer distance between the instrument and the volcanic plume. However, the light-mixing effect shows a similar strong dependence on the horizontal plume extension as for satellite observations and should be taken into account for the analysis of ground-based observations.

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SO<sub>2</sub> and BrO emissions of Masaya volcano from 2014 to 2020

Cited by 10 publications

References 85 publications

Observation and modelling of ozone-destructive halogen chemistry in a passively degassing volcanic plume

Observation and modelling of ozone-destructive halogen chemistry in a passively degassing volcanic plume

Wind Speed as a Dominant Source of Periodicities in Reported Emission Rates of Volcanic SO₂

Investigation of three-dimensional radiative transfer effects for UV–Vis satellite and ground-based observations of volcanic plumes

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SO&lt;sub&gt;2&lt;/sub&gt; and BrO emissions of Masaya volcano from 2014 to 2020

Cited by 10 publications

References 85 publications

Observation and modelling of ozone-destructive halogen chemistry in a passively degassing volcanic plume

Observation and modelling of ozone-destructive halogen chemistry in a passively degassing volcanic plume

Wind Speed as a Dominant Source of Periodicities in Reported Emission Rates of Volcanic SO2

Investigation of three-dimensional radiative transfer effects for UV–Vis satellite and ground-based observations of volcanic plumes

Contact Info

Product

Resources

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SO<sub>2</sub> and BrO emissions of Masaya volcano from 2014 to 2020

Wind Speed as a Dominant Source of Periodicities in Reported Emission Rates of Volcanic SO₂