Options
Von Glasow, R.
Loading...
Preferred name
Von Glasow, R.
6 results
Now showing 1 - 6 of 6
- PublicationOpen AccessThe tropospheric processing of acidic gases and hydrogen sulphide in volcanic gas plumes as inferred from field and model investigations(2006)
; ; ; ; ; ; ; ; ;Aiuppa, A.; Dipartimento CFTA, Universit `a di Palermo, Palermo, Italy ;Franco, A.; Dipartimento CFTA, Universit `a di Palermo, Palermo, Italy ;von Glasow, R.; Institut f ¨ ur Umweltphysik, University of Heidelberg, Germany ;Allen, A. G.; School of Geography, Earth and Environmental Sciences, University of Birmingham, UK ;D'Alessandro, W.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Mather, T. A.; Earth Science Department, University of Oxford, UK ;Pyle, D. M.; Earth Science Department, University of Oxford, UK ;Valenza, M.; Dipartimento CFTA, Universit `a di Palermo, Palermo, Italy; ; ; ; ; ; ; Improving the constraints on the atmospheric fate and depletion rates of acidic compounds persistently emitted by non-erupting (quiescent) volcanoes is important for quantitatively predicting the environmental impact of volcanic gas plumes. Here, we present new experimental data coupled with modelling studies to investigate the chemical processing of acidic volcanogenic species during tropospheric dispersion. Diffusive tube samplers were deployed at Mount Etna, a very active open-conduit basaltic volcano in eastern Sicily, and Vulcano Island, a closed-conduit quiescent volcano in the Aeolian Islands (northern Sicily). Sulphur dioxide (SO2), hydrogen sulphide (H2S), hydrogen chloride (HCl) and hydrogen fluoride (HF) concentrations in the volcanic plumes (typically several minutes to a few hours old) were repeatedly determined at distances from the summit vents ranging from 0.1 to 10 km, and under different environmental conditions. At both volcanoes, acidic gas concentrations were found to decrease exponentially with distance from the summit vents (e.g., SO2 decreases from 10 000 μg/m3 at 0.1 km from Etna’s vents down to 7 μg/m3 at 10 km distance), reflecting the atmospheric dilution of the plume within the acid gas-free background troposphere. Conversely, SO2/HCl, SO2/HF, and SO2/H2S ratios in the plume showed no systematic changes with plume aging, and fit source compositions within analytical error. Assuming that SO2 losses by reaction are small during short-range atmospheric transport within quiescent (ash-free) volcanic plumes, our observations suggest that, for these short transport distances, atmospheric reactions for H2S and halogens are also negligible. The one-dimensional model MISTRA was used to simulate quantitatively the evolution of halogen and sulphur compounds in the plume of Mt. Etna. Model predictions support the hypothesis of minor HCl chemical processing during plume transport, at least in cloud-free conditions. Larger variations in the modelled SO2/HCl ratios were predicted under cloudy conditions, due to heterogeneous chlorine cycling in the aerosol phase. The modelled evolution of the SO2/H2S ratios is found to be substantially dependent on whether or not the interactions of H2S with halogens are included in the model. In the former case, H2S is assumed to be oxidized in the atmosphere mainly by OH, which results in minor chemical loss for H2S during plume aging and produces a fair match between modelled and measured SO2/H2S ratios. In the latter case, fast oxidation of H2S by Cl leads to H2S chemical lifetimes in the early plume of a few seconds, and thus SO2 to H2S ratios that increase sharply during plume transport. This disagreement between modelled and observed plume compositions suggests that more in-detail kinetic investigations are required for a proper evaluation of H2S chemical processing in volcanic plumes.222 116 - PublicationOpen AccessThe tropospheric processing of acidic gases and hydrogen sulphide in volcanic gas plumes as inferred from field and model investigations(2007-03-13)
; ; ; ; ; ; ; ; ;Aiuppa, A.; Università di Palermo, Dipartimento CFTA ;Franco, A.; Università di Palermo, Dipartimento CFTA ;von Glasow, R.; Institut für Umweltphysik, University of Heidelberg, Germany ;Allen, A. G.; School of Geography, Earth and Environmental Sciences, University of Birmingham, UK ;D'Alessandro, W.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Mather, T. A.; Earth Science Department, University of Oxford, UK ;Pyle, D. M.; Earth Science Department, University of Oxford, UK ;Valenza, M.; Università di Palermo, Dipartimento CFTA; ; ; ; ; ; ; Improving the constraints on the atmospheric fate and depletion rates of acidic compounds persistently emitted by non-erupting (quiescent) volcanoes is important for quantitatively predicting the environmental impact of volcanic gas plumes. Here, we present new experimental data coupled with modelling studies to investigate the chemical processing of acidic volcanogenic species during tropospheric dispersion. Diffusive tube samplers were deployed at Mount Etna, a very active open-conduit basaltic volcano in eastern Sicily, and Vulcano Island, a closed-conduit quiescent volcano in the Aeolian Islands (northern Sicily). Sulphur dioxide (SO2), hydrogen sulphide (H2S), hydrogen chloride (HCl) and hydrogen fluoride (HF) concentrations in the volcanic plumes (typically several minutes to a few hours old) were repeatedly determined at distances from the summit vents ranging from 0.1 to ~10 km, and under different environmental conditions. At both volcanoes, acidic gas concentrations were found to decrease exponentially with distance from the summit vents (e.g., SO2 decreases from ~10,000 μg/m3 at 0.1 km from Etna’s vents down to ~7 _μg/m3 at ~10km distance), reflecting the atmospheric dilution of the plume within the acid gas-free background troposphere. Conversely, SO2/HCl, SO2/HF, and SO2/H2S ratios in the plume showed no systematic changes with plume aging, and fit source compositions within analytical error. Assuming that SO2 losses by reaction are small during short-range atmospheric transport within quiescent (ash-free) volcanic plumes, our observations suggest that, for these short transport distances, atmospheric reactions for H2S and halogens are also negligible. The one-dimensional model MISTRA was used to simulate quantitatively the evolution of halogen and sulphur compounds in the plume of Mt. Etna. Model predictions support the hypothesis of minor HCl chemical processing during plume transport, at least in cloud-free conditions. Larger variations in the modelled SO2/HCl ratios were predicted under cloudy conditions, due to heterogeneous chlorine cycling in the aerosol phase. The modelled evolution of the SO2/H2S ratios is found to be substantially dependent on whether or not the interactions of H2S with halogens are included in the model. In the former case, H2S is assumed to be oxidized in the atmosphere mainly by OH, which results in minor chemical loss for H2S during plume aging and produces a fair match between modelled and measured SO2/H2S ratios. In the latter case, fast oxidation of H2S by Cl leads to H2S chemical lifetimes in the early plume of a few seconds, and thus SO2 to H2S ratios that increase sharply during plume transport. This disagreement between modelled and observed plume compositions suggests that more in-detail kinetic investigations are required for a proper evaluation of H2S chemical processing in volcanic plumes.167 92 - PublicationRestrictedGas emission strength and evolution of the molar ratio of BrO/SO2 in the plume of Nyiragongo in comparison to Etna(2015-01-12)
; ; ; ; ; ; ; ; ; ;Bobrowski, N.; Institut für Umweltphysik, University of Heidelberg, Heidelberg, Germany ;von Glasow, R.; 2Centre for Ocean and Atmospheric Sciences, School of Environmental Sciences, University of East Anglia, Norwich, United Kingdom ;Giuffrida, G. B.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Tedesco, D.; Department of Environmental Sciences, Second University of Napoli, Caserta, Italy ;Aiuppa, A.; Dipartimento Scienze della Terra e del Mare, University of Palermo, Palermo, Italy, ;Yalire, M.; Observatoire Volcanologique de Goma, Goma, Democratic Republic of Congo ;Arellano, S.; Department of Earth and Space Sciences, Chalmers University of Technology, Göteborg, Sweden ;Johansson, M.; Department of Earth and Space Sciences, Chalmers University of Technology, Göteborg, Sweden ;Galle, B.; Department of Earth and Space Sciences, Chalmers University of Technology, Göteborg, Sweden; ; ; ; ; ; ; ; Airborne and ground-based differential optical absorption spectroscopy observations have been carried out at the volcano Nyiragongo (Democratic Republic of Congo) tomeasure SO2 and bromine monoxide (BrO) in the plume inMarch 2004 and June 2007, respectively. Additionally filter pack andmulticomponent gas analyzer system (Multi-GAS)measurements were carried out in June 2007. Ourmeasurements provide valuable information on the chemical composition of the volcanic plume emitted fromthe lava lake of Nyiragongo. The main interest of this study has been to investigate for the first time the bromine emission flux of Nyiragongo (a rift volcano) and the BrO formation in its volcanic plume. Measurement data and results from a numerical model of the evolution of BrO in Nyiragongo volcanic plume are compared with earlier studies of the volcanic plume of Etna (Italy). Even though the bromine flux from Nyiragongo (2.6 t/d) is slightly greater than that from Etna (1.9 t/d), the BrO/SO2 ratio (maximum 7 × 10 5) is smaller than in the plume of Etna (maximum 2.1 × 10 4). A one-dimensional photochemical model to investigate halogen chemistry in the volcanic plumes of Etna and Nyiragongo was initialized using data from Multi-GAS and filter pack measurements. Model runs showed that the differences in the composition of volcanic volatiles led to a smaller fraction of total bromine being present as BrO in the Nyiragongo plume and to a smaller BrO/SO2 ratio.344 35 - PublicationOpen AccessQuantification of the depletion of ozone in the plume of Mount Etna(2015-03-09)
; ; ; ; ; ;Surl, L.; Centre for Ocean and Atmospheric Sciences, School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, UK ;Donohoue, D.; Centre for Ocean and Atmospheric Sciences, School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, UK - now at: Department of Chemistry, Lawrence University, Appleton, Wisconsin, 54911, USA ;Aiuppa, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Bobrowski, N.; Institut für Umweltphysik, Universität Heidelberg, Im Neuenheimer Feld 229, 69120 Heidelberg, Germany ;von Glasow, R.; Centre for Ocean and Atmospheric Sciences, School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, UK; ; ; ; Volcanoes are an important source of inorganic halogen species into the atmosphere. Chemical processing of these species generates oxidised, highly reactive, halogen species which catalyse considerable O3 destruction within volcanic plumes. A campaign of ground-based in situ O3, SO2 and meteorology measurements was undertaken at the summit of Mount Etna volcano in July/August 2012. At the same time, spectroscopic measurements were made of BrO and SO2 columns in the plume downwind. Depletions of ozone were seen at all in-plume measurement locations, with average O3 depletions ranging from 11–35 nmol mol1 (15–45 %). Atmospheric processing times of the plume were estimated to be between 1 and 4 min. A 1-D numerical model of early plume evolution was also used. It was found that in the early plume O3 was destroyed at an approximately constant rate relative to an inert plume tracer. This is ascribed to reactive halogen chemistry, and the data suggests the majority of the reactive halogen that destroys O3 in the early plume is generated within the crater, including a substantial proportion generated in a high-temperature “effective source region” immediately after emission. The model could approximately reproduce the main measured features of the ozone chemistry. Model results show a strong dependence of the near-vent bromine chemistry on the presence or absence of volcanic NOx emissions and suggest that near-vent ozone measurements can be used as a qualitative indicator of NOx emission.207 127 - PublicationOpen AccessReactive halogen chemistry in volcanic plumes(2007)
; ; ; ; ; ; ; ;Bobrowski, N.; Institut für Umweltphysik, University of Heidelberg, Germany ;von Glasow, R.; Institut für Umweltphysik, University of Heidelberg, Germany ;Aiuppa, A.; Dipartimento CFTA, Universita di Palermo, Italy ;Inguaggiato, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Louban, I.; Institut für Umweltphysik, University of Heidelberg, Germany ;Ibrahim, O. W.; Institut für Umweltphysik, University of Heidelberg, Germany ;Platt, U.; Institut für Umweltphysik, University of Heidelberg, Germany; ; ; ; ; ; Bromine monoxide (BrO) and sulphur dioxide (SO2) abundances as a function of the distance from the source were measured by ground-based scattered-light Multi AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) in the volcanic plumes of Mt. Etna on Sicily, Italy in August-October 2004 and May 2005 and Villarica in Chile in November 2004. BrO and SO2 spatial distributions in a cross section of Mt. Etna’s plume were also determined by Imaging DOAS. We observed an increase in the BrO/SO2 ratio in the plume from below the detection limit near the vent to about 4.5 x 10-4 at 19 km (Mt. Etna) and to about 1.3 x 10-4 at 3 km (Villarica) distance, respectively. Additional attempts were undertaken to evaluate the compositions of individual vents on Mt. Etna. Furthermore, we detected the halogen species ClO and OClO. This is the first time that OClO could be detected in a volcanic plume. Using calculated thermodynamic equilibrium compositions as input data for a one–dimensional photochemical model, we could reproduce the observed BrO and SO2 vertical columns in the plume and their ratio as function of distance from the volcano as well as vertical BrO and SO2 profiles across the plume with current knowledge of multiphase halogen chemistry, but only when we assumed the existence of an ”effective source region”, where volcanic volatiles and ambient air are mixed at about 600°C (in the proportions of 60% and 40%, respectively)199 819 - PublicationRestrictedThe effects of volcanic eruptions on atmospheric chemistry(2009-06-15)
; ; ; ;Von Glasow, R.; School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, UK ;Bobrowski, N.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Kern, C.; Institut für Umweltphysik, Universität Heidelberg, Im Neuenheimer Feld 229, 69120 Heidelberg, Germany; ; Volcanoes are very strong sources of sulphur, acids and other gases, as well as particles, that are of atmospheric relevance. Some gases only behave as passive tracers, others affect the formation, growth or chemical characteristics of aerosol particles and many lead to adverse effects on vegetation and human health when deposited in the vicinity of volcanoes. In this article the main effects of volcanic emissions on atmospheric chemistry are discussed, with a focus on sulphur and halogen compounds, and to a smaller extent on climate. We primarily focus on quiescent degassing but the main effects of explosive eruptions on the troposphere and stratosphere are covered as well. The key distinction between chemistry in magmatic and hydrothermal settings and the atmosphere is that the atmosphere is oxidising whereas the chemistry is typically reducing in the former cases due to very low oxygen concentrations. Rapid catalytic cycles involving radicals are a further characteristic of atmospheric chemistry. Most reaction cycles involve the photolysis of molecules as a key part of the reaction chains. Recent measurements of halogen radicals in volcanic plumes showed that volcanic plumes are chemically very active. We explain the formation mechanism of halogen oxides in plumes as well as their relevance for the atmosphere.668 53