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An advanced modeling study on the impacts and atmospheric implications of multiphase dimethyl sulfide chemistry

Hoffmann, Erik Hans; Tilgner, Andreas; Schrödner, Roland LU ; Braeura, Peter; Wolke, Ralf and Herrmann, Hartmut (2016) In The Proceedings of the National Academy of Sciences 113(42). p.11776-11781
Abstract
Oceans dominate emissions of dimethyl sulfide (DMS), the major natural sulfur source. DMS is important for the formation of non-sea salt sulfate (nss-SO42−) aerosols and secondary particulate matter over oceans and thus, significantly influence global climate. The mechanism of DMS oxidation has accordingly been investigated in several different model studies in the past. However, these studies had restricted oxidation mechanisms that mostly underrepresented important aqueous-phase chemical processes. These neglected but highly effective processes strongly impact direct product yields of DMS oxidation, thereby affecting the climatic influence of aerosols. To address these shortfalls, an extensive multiphase DMS chemistry mechanism, the... (More)
Oceans dominate emissions of dimethyl sulfide (DMS), the major natural sulfur source. DMS is important for the formation of non-sea salt sulfate (nss-SO42−) aerosols and secondary particulate matter over oceans and thus, significantly influence global climate. The mechanism of DMS oxidation has accordingly been investigated in several different model studies in the past. However, these studies had restricted oxidation mechanisms that mostly underrepresented important aqueous-phase chemical processes. These neglected but highly effective processes strongly impact direct product yields of DMS oxidation, thereby affecting the climatic influence of aerosols. To address these shortfalls, an extensive multiphase DMS chemistry mechanism, the Chemical Aqueous Phase Radical Mechanism DMS Module 1.0, was developed and used in detailed model investigations of multiphase DMS chemistry in the marine boundary layer. The performed model studies confirmed the importance of aqueous-phase chemistry for the fate of DMS and its oxidation products. Aqueous-phase processes significantly reduce the yield of sulfur dioxide and increase that of methyl sulfonic acid (MSA), which is needed to close the gap between modeled and measured MSA concentrations. Finally, the simulations imply that multiphase DMS oxidation produces equal amounts of MSA and sulfate, a result that has significant implications for nss-SO42− aerosol formation, cloud condensation nuclei concentration, and cloud albedo over oceans. Our findings show the deficiencies of parameterizations currently used in higher-scale models, which only treat gas-phase chemistry. Overall, this study shows that treatment of DMS chemistry in both gas and aqueous phases is essential to improve the accuracy of model predictions. (Less)
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author
publishing date
type
Contribution to journal
publication status
published
subject
keywords
marine multiphase chemistry, dimethyl sulfide, multiphase modeling, CAPRAM, marine aerosols
in
The Proceedings of the National Academy of Sciences
volume
113
issue
42
pages
11776 - 11781
external identifiers
  • scopus:84991699789
DOI
10.1073/pnas.1606320113
language
English
LU publication?
no
id
9af8b87a-736d-47ba-b700-99037dc60d2d
date added to LUP
2017-07-05 14:41:41
date last changed
2017-09-24 05:13:02
@article{9af8b87a-736d-47ba-b700-99037dc60d2d,
  abstract     = {Oceans dominate emissions of dimethyl sulfide (DMS), the major natural sulfur source. DMS is important for the formation of non-sea salt sulfate (nss-SO42−) aerosols and secondary particulate matter over oceans and thus, significantly influence global climate. The mechanism of DMS oxidation has accordingly been investigated in several different model studies in the past. However, these studies had restricted oxidation mechanisms that mostly underrepresented important aqueous-phase chemical processes. These neglected but highly effective processes strongly impact direct product yields of DMS oxidation, thereby affecting the climatic influence of aerosols. To address these shortfalls, an extensive multiphase DMS chemistry mechanism, the Chemical Aqueous Phase Radical Mechanism DMS Module 1.0, was developed and used in detailed model investigations of multiphase DMS chemistry in the marine boundary layer. The performed model studies confirmed the importance of aqueous-phase chemistry for the fate of DMS and its oxidation products. Aqueous-phase processes significantly reduce the yield of sulfur dioxide and increase that of methyl sulfonic acid (MSA), which is needed to close the gap between modeled and measured MSA concentrations. Finally, the simulations imply that multiphase DMS oxidation produces equal amounts of MSA and sulfate, a result that has significant implications for nss-SO42− aerosol formation, cloud condensation nuclei concentration, and cloud albedo over oceans. Our findings show the deficiencies of parameterizations currently used in higher-scale models, which only treat gas-phase chemistry. Overall, this study shows that treatment of DMS chemistry in both gas and aqueous phases is essential to improve the accuracy of model predictions.},
  author       = {Hoffmann, Erik Hans and Tilgner, Andreas and Schrödner, Roland and Braeura, Peter and Wolke, Ralf and Herrmann, Hartmut},
  keyword      = {marine multiphase chemistry,dimethyl sulfide,multiphase modeling,CAPRAM,marine aerosols},
  language     = {eng},
  month        = {10},
  number       = {42},
  pages        = {11776--11781},
  series       = {The Proceedings of the National Academy of Sciences},
  title        = {An advanced modeling study on the impacts and atmospheric implications of multiphase dimethyl sulfide chemistry},
  url          = {http://dx.doi.org/10.1073/pnas.1606320113},
  volume       = {113},
  year         = {2016},
}