Atmospheric transport and deposition of Indonesian volcanic emissions

A regional climate model has been used to study the transport and deposition of sulfur (SO<sub>2</sub> and SO<sub>4</sub><sup>2-</sup>) and PbCl<sub>2</sub> emissions from Indonesian volcanoes. The sensitivity of the atmospheric loss of these trace spe...

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Main Authors: M. A. Pfeffer, B. Langmann, H.-F. Graf
Format: Article
Language:English
Published: Copernicus Publications 2006-01-01
Series:Atmospheric Chemistry and Physics
Online Access:http://www.atmos-chem-phys.net/6/2525/2006/acp-6-2525-2006.pdf
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spelling doaj-849bfcd4de564955a7d4951aa7e8a62a2020-11-24T22:49:23ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242006-01-016925252537Atmospheric transport and deposition of Indonesian volcanic emissionsM. A. PfefferB. LangmannH.-F. GrafA regional climate model has been used to study the transport and deposition of sulfur (SO<sub>2</sub> and SO<sub>4</sub><sup>2-</sup>) and PbCl<sub>2</sub> emissions from Indonesian volcanoes. The sensitivity of the atmospheric loss of these trace species to meteorological conditions and their solubility was examined. Two experiments were conducted: 1) volcanic sulfur released as primarily SO<sub>2</sub> and subject to transport, deposition, and oxidation to SO<sub>4</sub><sup>2-</sup>; and 2) PbCl<sub>2</sub> released as an infinitely soluble passive tracer subject to only transport and deposition. The first experiment was used to calculate SO<sub>2</sub> loss rates from each active Indonesian volcano producing an annual mean loss rate for all volcanoes of 1.1&times;10<sup>-5</sup> s<sup>-1</sup>, or an e-folding rate of approximately 1 day. SO<sub>2</sub> loss rate was found to vary seasonally, be poorly correlated with wind speed, and uncorrelated with temperature or relative humidity. The variability of SO<sub>2</sub> loss rates is found to be correlated with the variability of wind speeds, suggesting that it is much more difficult to establish a 'typical'' SO<sub>2</sub> loss rate for volcanoes that are exposed to changeable winds. Within an average distance of 70 km away from the active Indonesian volcanoes, 53% of SO<sub>2</sub> loss is due to conversion to SO<sub>4</sub><sup>2-</sup>, 42% due to dry deposition, and 5% due to lateral transport away from the dominant direction of plume travel. The solubility of volcanic emissions in water is shown to influence their atmospheric transport and deposition. High concentrations of PbCl<sub>2</sub> are predicted to be deposited near to the volcanoes while volcanic S travels further away until removal from the atmosphere primarily via the wet deposition of H<sub>2</sub>SO<sub>4</sub>. The ratio of the concentration of PbCl<sub>2</sub> to SO<sub>2</sub> is found to exponentially decay at increasing distance from the volcanoes. The more rapid removal of highly soluble species should be considered when observing SO<sub>2</sub> in an aged plume and relating this concentration to other volcanic species. An assumption that the ratio between the concentrations of highly soluble volcanic compounds and SO<sub>2</sub> within a plume is equal to that observed in fumarolic gases is reasonable at small distances from the volcanic vent, but will result in an underestimation of the emission flux of highly soluble species.http://www.atmos-chem-phys.net/6/2525/2006/acp-6-2525-2006.pdf
collection DOAJ
language English
format Article
sources DOAJ
author M. A. Pfeffer
B. Langmann
H.-F. Graf
spellingShingle M. A. Pfeffer
B. Langmann
H.-F. Graf
Atmospheric transport and deposition of Indonesian volcanic emissions
Atmospheric Chemistry and Physics
author_facet M. A. Pfeffer
B. Langmann
H.-F. Graf
author_sort M. A. Pfeffer
title Atmospheric transport and deposition of Indonesian volcanic emissions
title_short Atmospheric transport and deposition of Indonesian volcanic emissions
title_full Atmospheric transport and deposition of Indonesian volcanic emissions
title_fullStr Atmospheric transport and deposition of Indonesian volcanic emissions
title_full_unstemmed Atmospheric transport and deposition of Indonesian volcanic emissions
title_sort atmospheric transport and deposition of indonesian volcanic emissions
publisher Copernicus Publications
series Atmospheric Chemistry and Physics
issn 1680-7316
1680-7324
publishDate 2006-01-01
description A regional climate model has been used to study the transport and deposition of sulfur (SO<sub>2</sub> and SO<sub>4</sub><sup>2-</sup>) and PbCl<sub>2</sub> emissions from Indonesian volcanoes. The sensitivity of the atmospheric loss of these trace species to meteorological conditions and their solubility was examined. Two experiments were conducted: 1) volcanic sulfur released as primarily SO<sub>2</sub> and subject to transport, deposition, and oxidation to SO<sub>4</sub><sup>2-</sup>; and 2) PbCl<sub>2</sub> released as an infinitely soluble passive tracer subject to only transport and deposition. The first experiment was used to calculate SO<sub>2</sub> loss rates from each active Indonesian volcano producing an annual mean loss rate for all volcanoes of 1.1&times;10<sup>-5</sup> s<sup>-1</sup>, or an e-folding rate of approximately 1 day. SO<sub>2</sub> loss rate was found to vary seasonally, be poorly correlated with wind speed, and uncorrelated with temperature or relative humidity. The variability of SO<sub>2</sub> loss rates is found to be correlated with the variability of wind speeds, suggesting that it is much more difficult to establish a 'typical'' SO<sub>2</sub> loss rate for volcanoes that are exposed to changeable winds. Within an average distance of 70 km away from the active Indonesian volcanoes, 53% of SO<sub>2</sub> loss is due to conversion to SO<sub>4</sub><sup>2-</sup>, 42% due to dry deposition, and 5% due to lateral transport away from the dominant direction of plume travel. The solubility of volcanic emissions in water is shown to influence their atmospheric transport and deposition. High concentrations of PbCl<sub>2</sub> are predicted to be deposited near to the volcanoes while volcanic S travels further away until removal from the atmosphere primarily via the wet deposition of H<sub>2</sub>SO<sub>4</sub>. The ratio of the concentration of PbCl<sub>2</sub> to SO<sub>2</sub> is found to exponentially decay at increasing distance from the volcanoes. The more rapid removal of highly soluble species should be considered when observing SO<sub>2</sub> in an aged plume and relating this concentration to other volcanic species. An assumption that the ratio between the concentrations of highly soluble volcanic compounds and SO<sub>2</sub> within a plume is equal to that observed in fumarolic gases is reasonable at small distances from the volcanic vent, but will result in an underestimation of the emission flux of highly soluble species.
url http://www.atmos-chem-phys.net/6/2525/2006/acp-6-2525-2006.pdf
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