scholarly journals Isotopic fractionation of carbonyl sulfide in the atmosphere: Implications for the source of background stratospheric sulfate aerosol

2002 ◽  
Vol 29 (10) ◽  
pp. 112-1-112-4 ◽  
Author(s):  
Fok-Yan T. Leung ◽  
Agustín J. Colussi ◽  
Michael R. Hoffmann ◽  
Geoffrey C. Toon
Keyword(s):  
Carbonyl Sulfide ◽  
Isotopic Fractionation ◽  
Sulfate Aerosol

scholarly journals Ultraviolet absorption cross sections of carbonyl sulfide isotopologues OC<sup>32</sup>S, OC<sup>33</sup>S, OC<sup>34</sup>S and O<sup>13</sup>CS: isotopic fractionation in photolysis and atmospheric implications

2011 ◽  
Vol 11 (19) ◽  
pp. 10293-10303 ◽  
Author(s):  
S. Hattori ◽  
S. O. Danielache ◽  
M. S. Johnson ◽  
J. A. Schmidt ◽  
H. G. Kjaergaard ◽  
...  
Keyword(s):  
Cross Sections ◽  
Carbonyl Sulfide ◽  
Isotopic Fractionation ◽  
High Energy ◽  
Ultraviolet Absorption ◽  
Absorption Cross ◽  
Rare Isotopes ◽  
Mass Dependent ◽  
Franck Condon ◽  
Energy Side

Abstract. We report measurements of the ultraviolet absorption cross sections of OC32S, OC33S, OC34S and O13CS from 195 to 260 nm. The OCS isotopologues were synthesized from isotopically-enriched elemental sulfur by reaction with carbon monoxide. The measured cross section of OC32S is consistent with literature spectra recorded using natural abundance samples. Relative to the spectrum of the most abundant isotopologue, substitution of heavier rare isotopes has two effects. First, as predicted by the reflection principle, the Gaussian-based absorption envelope becomes slightly narrower and blue-shifted. Second, as predicted by Franck-Condon considerations, the weak vibrational structure is red-shifted. Sulfur isotopic fractionation constants (33ε, 34ε) as a function of wavelength are not highly structured, and tend to be close to zero on average on the high energy side and negative on the low energy side. The integrated photolysis rate of each isotopologue at 20 km, the approximate altitude at which most OCS photolysis occurs, was calculated. Sulfur isotopic fractionation constants at 20 km altitude are (−3.7 ± 4.5)‰ and (1.1 ± 4.2)‰ for 33ε and 34ε, respectively, which is inconsistent with the previously estimated large fractionation of over 73‰ in 34ε. This demonstrates that OCS photolysis does not produce sulfur isotopic fractionation of more than ca. 5‰, suggesting OCS may indeed be a significant source of background stratospheric sulfate aerosols. Finally, the predicted isotopic fractionation constant for 33S excess (33E) in OCS photolysis is (−4.2 ± 6.6)‰, and thus photolysis of OCS is not expected to be the source of the non-mass-dependent signature observed in modern and Archaean samples.

Sulfur Isotopic Fractionation of Carbonyl Sulfide during Degradation by Soil Bacteria

2016 ◽  
Vol 50 (7) ◽  
pp. 3537-3544 ◽  
Author(s):  
Kazuki Kamezaki ◽  
Shohei Hattori ◽  
Takahiro Ogawa ◽  
Sakae Toyoda ◽  
Hiromi Kato ◽  
...  
Keyword(s):  
Soil Bacteria ◽  
Carbonyl Sulfide ◽  
Isotopic Fractionation

scholarly journals On the isotopic fingerprint exerted on carbonyl sulfide by the stratosphere

2012 ◽  
Vol 12 (9) ◽  
pp. 25329-25353 ◽  
Author(s):  
J. A. Schmidt ◽  
S. Hattori ◽  
N. Yoshida ◽  
S. Nanbu ◽  
M. S. Johnson ◽  
...  
Keyword(s):  
Cross Sections ◽  
Potential Energy Surfaces ◽  
Carbonyl Sulfide ◽  
Isotopic Fractionation ◽  
Data Sets ◽  
Mechanical Formalism ◽  
Model Study ◽  
Quantum Mechanical Formalism ◽  
Energy Surfaces ◽  
Good Agreement

Abstract. The isotopic fractionation in OCS photolysis is studied theoretically from first principles. UV absorption cross sections for OCS, OC33S, OC34S, OC36S and O13CS are calculated using the time-depedent quantum mechanical formalism and recent potential energy surfaces for the lowest four singlet and lowest four triplet electronic states. The calculated isotopic fractionations as a function of wavelength are in good agreement with recent measurements by Hattori et al. (2011) and indicate that photolysis leads to only a small enrichment of 34S in the remaining pool of OCS. A simple stratospheric model is constructed taking into account the main stratospheric sink reactions of OCS and it is found that stratospheric removal overall slightly favors light OCS in constrast to the findings of Leung et al. (2002). These results show, based on isotopic considerations, that OCS is an acceptable source of background stratosperic sulfate aerosol in agreement with a recent model study of Brühl et al. (2012). The 13C isotopic fractionation due to photolysis of OCS is significant and will leave a strong signal in the pool of remaining OCS making it a candidate for tracing using the ACE-FTS and MIPAS data sets.

scholarly journals Ultraviolet absorption cross sections of carbonyl sulfide isotopologues OC<sup>32</sup>S, OC<sup>33</sup>S, OC<sup>34</sup>S and O<sup>13</sup>CS: isotopic fractionation in photolysis and atmospheric implications

2011 ◽  
Vol 11 (7) ◽  
pp. 20487-20520 ◽  
Author(s):  
S. Hattori ◽  
S. O. Danielache ◽  
M. S. Johnson ◽  
J. A. Schmidt ◽  
H. G. Kjaergaard ◽  
...  
Keyword(s):  
Cross Sections ◽  
Carbonyl Sulfide ◽  
Isotopic Fractionation ◽  
High Energy ◽  
Ultraviolet Absorption ◽  
Absorption Cross ◽  
Rare Isotopes ◽  
Mass Dependent ◽  
Franck Condon ◽  
Energy Side

Abstract. We report measurements of the ultraviolet absorption cross sections of OC32S, OC33S, OC34S and O13CS from 195 to 260 nm. The OCS isotopologues were synthesized from isotopically-enriched elemental sulfur by reaction with carbon monoxide. The measured cross section of OC32S is consistent with literature spectra recorded using natural abundance samples. Relative to the spectrum of the most abundant isotopologue, substitution of heavier rare isotopes has two effects. First, as predicted by the reflection principle, the Gaussian-based absorption envelope becomes slightly more narrow and blue-shifted. Second, as predicted by Franck-Condon considerations, the weak vibrational structure is red-shifted. Sulfur isotopic fractionation constants (33ε, 34ε) as a function of wavelength are not highly structured, and tend to be close to zero on average on the high energy side and negative on the low energy side. Since OCS photolysis occurs in the lower stratosphere, the integrated photolysis rate of each isotopologue at 20 km was calculated. Sulfur isotopic fractionation constants at 20 km altitude are (−3.7 ± 4.5) ‰ and (1.1 ± 4.2) ‰ for 33ε and 34ε, respectively, which is inconsistent with the previously estimated large fractionation of over 73 ‰ in 34ε. This demonstrates that OCS photolysis does not produce sulfur isotopic fractionation of more than ca. 5 ‰, suggesting OCS may be the source of background stratospheric sulfate aerosols. Finally, the predicted isotopic fractionation constant for 33S excess (33E) in OCS photolysis is (−4.2 ± 6.6) ‰, and thus photolysis of OCS is not expected to be the source of the non-mass-dependent signature observed in modern and Archaean samples.

scholarly journals Isotopic Fractionation of Sulfur in Carbonyl Sulfide by Carbonyl Sulfide Hydrolase of Thiobacillus thioparus THI115

2017 ◽  
Vol 32 (4) ◽  
pp. 367-375 ◽  
Author(s):  
Takahiro Ogawa ◽  
Shohei Hattori ◽  
Kazuki Kamezaki ◽  
Hiromi Kato ◽  
Naohiro Yoshida ◽  
...  
Keyword(s):  
Carbonyl Sulfide ◽  
Isotopic Fractionation ◽  
Thiobacillus Thioparus

scholarly journals A novel approach to sulfate geoengineering with surface emissions of carbonyl sulfide

2021 ◽  
Author(s):  
Ilaria Quaglia ◽  
Daniele Visioni ◽  
Giovanni Pitari ◽  
Ben Kravitz
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Indirect Effects ◽  
Radiative Forcing ◽  
Climate Model ◽  
Stratospheric Ozone ◽  
Carbonyl Sulfide ◽  
Sulfate Aerosol ◽  
Stratospheric Water Vapor ◽  
Surface Emission

Abstract. Sulfate geoengineering (SG) methods based on lower stratospheric tropical injection of sulfur dioxide (SO2) have been widely discussed in recent years, focusing on the direct and indirect effects they would have on the climate system. Here a potential alternative method is discussed, where sulfur emissions are located at the surface in the form of carbonyl sulfide (COS) gas. A time-dependent chemistry-climate model experiment is designed from year 2021 to 2055, assuming a 40 Tg-S/yr artificial global flux of COS, geographically distributed following the present day anthropogenic COS surface emissions. The budget of COS and sulfur species is discussed, as well as the effects of SG-COS on the stratospheric sulfate aerosol optical depth (Δ τ = 0.080 in years 2046–2055), aerosol effective radius (0.46 μm), surface SOx deposition (+8.7 %) and tropopause radiative forcing (RF) (−2.0 W/m2 for clear sky conditions and −1.5 W/m2 including the cloud adjustment). Indirect effects on ozone, methane and stratospheric water vapor are also considered, along with the COS direct contribution (with an overall gas phase global radiative forcing of +0.23 W/m2). According to our model results, the resulting net RF of this SG-COS experiment is −1.3 W/m2 for the year 2050, and it is comparable to the corresponding RF of −1.7 W/m2 obtained with a sustained injection of 4 Tg-S/yr in the tropical lower stratosphere in the form of SO2 (SG-SO2, able to produce a comparable increase of the sulfate aerosol optical depth). Significant changes of the stratospheric ozone response are found in SG-COS with respect to SG-SO2 (+4.9 DU versus +1.5 DU, globally). According to the model results, the resulting UVB perturbation at the surface accounts to −4.3 % as a global-annual average (versus −2.4 % in the SG-SO2 case), with a springtime Antarctic decrease of −2.7 % (versus a +5.8 % increase in the SG-SO2 experiment). Overall, we find that an increase in COS surface emission may be feasible, and produce a more latitudinally-uniform forcing without the need for the deployment of stratospheric aircrafts.

scholarly journals Large volume sample system for measuring sulfur isotopic compositions of carbonyl sulfide

2018 ◽  
Author(s):  
Kazuki Kamezaki ◽  
Shohei Hattori ◽  
Enno Bahlmann ◽  
Naohiro Yoshida
Keyword(s):  
Collection Efficiency ◽  
Carbonyl Sulfide ◽  
Isotopic Fractionation ◽  
Isotopic Analysis ◽  
Ambient Air ◽  
Sampling System ◽  
Abstract Knowledge ◽  
Global Signal ◽  
Significant Difference ◽  
Institute Of Technology

Abstract. Knowledge related to sulfur isotopic composition of carbonyl sulphide (OCS or COS), the most abundant atmospheric sulfur species, remains scarce. Earlier method developed for sulfur isotopic analysis for OCS using S+ fragmentation is inapplicable for ambient air samples because of the large samples required (approx. 500 L of 500 pmol mol−1 OCS). To overcome this difficulty, herein we present a new sampling system for collecting approx. 10 nmol of OCS from ambient air coupled with a purification system. Salient system features are (i) accommodation of samples up to 500 L (= approx. 10 nmol) of air at 5 L min−1, (ii) portability of 7 inch tubes (approx. 1 cm3) for preserving samples, and (iii) purification OCS from other compounds such as CO2. We tested the OCS collection efficiency of the systems and sulfur isotopic fractionation during sampling. Results show precision (1σ) of δ33S(OCS), δ34S(OCS), and Δ33S(OCS) values, respectively, as 0.4 ‰, 0.2 ‰, and 0.4 ‰. Additionally, this report presents diurnal variation of δ34S(OCS) values collected from ambient air at Suzukakedai campus of Tokyo Institute of Technology located in Yokohama, Japan. The observed OCS concentrations and δ34S(OCS) values were, respectively, 447–520 pmol mol−1 and from 10.4 ‰ to 10.7 ‰. No significant difference was found between values obtained during the day and night. The observed δ34S(OCS) values in ambient air differed greatly from previously reported values ((4.9 ± 0.3) ‰) for compressed air collected at Kawasaki, Japan, presumably because of sampling conditions and collection processes for that sample. Consequently, previous values of δ34S(OCS) = (4.9 ± 0.3) ‰ were not representative samples for a global signal. When considering (10.5 ± 0.4) ‰ is postulated as the global signal of δ34S(OCS), this revised δ34S(OCS) value is consistent with previous estimation based on terrestrial and oceanic sulfur sources. The δ34S(OCS) value explains the reported δ34S(OCS) values for background stratospheric sulfate. The system presented herein is useful for application of δ34S(OCS) for investigation of OCS sources and sinks in the troposphere to elucidate its cycle and its contribution to background stratospheric sulfate.

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