Modeling the pathways of generation of O-MIF in tropospheric sulfates

Tommaso Galeazzo 1 Slimane Bekki 1 Erwan Martin 2
1 STRATO - LATMOS
LATMOS - Laboratoire Atmosphères, Milieux, Observations Spatiales
Abstract : Volcanic emissions are among the major natural sources of sulfur and SO2 in the atmosphere. However, there are still significant uncertainties pertaining to atmospheric oxidation pathways of SO2 and its implications on the budget of atmospheric sulfate particles. Mass- independent fractionations (MIF) can be used as quantitative markers to detect atmospheric pathways of reaction. The majority of the oxygen isotopic anomalies observed in sulfates originate from ozone and it is transferred during tropospheric oxidation of SO2. An oxygen isotopic chemistry scheme for sulfate is implemented into a photochemical box- model (CiTTyCAT) that contains a detailed description of tropospheric chemistry. The chemical scheme has been extended with heterogeneous chemistry of S(IV) and S(VI) species. The mass transfer and oxidation in liquid phases are explicitly treated with no assumptions regarding phase equilibria of soluble gases, and the acid-base equilibrium. The oxygen isotopes MIF scheme has been implemented to simulate the evolution of O-MIF of tropospheric sulfate. The model is used to determine pathways of sulfate formation during the oxidation of volcanic SO2. Comparisons within isotopic compositions of sulfate from volcanic deposits and modeled O-MIF suggest that SO2 is oxidized by O2/TMI in the liquid phase within the volcanic plume.
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Submitted on : Wednesday, January 17, 2018 - 4:44:30 PM
Last modification on : Tuesday, May 14, 2019 - 11:05:29 AM

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  • HAL Id : hal-01686737, version 1

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Tommaso Galeazzo, Slimane Bekki, Erwan Martin. Modeling the pathways of generation of O-MIF in tropospheric sulfates. GOLDSCHMIDT 2017, Aug 2017, Paris, France. ⟨hal-01686737⟩

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