12:00 PM - 12:15 PM
[AAS07-11] Atmospheric sulfur cycle elucidated by isotopologue measurements
–JpSAC Young Scientist Award Lecture–
★Invited Papers
Keywords:Sulfate aerosols, Sulfur cycle, Triple oxygen isotopic composition
Atmospheric sulfur cycle is important by forming atmospheric sulfate (SO42−) aerosols which have a notable but uncertain impact on the global radiation budget and cloud lifetimes. Atmospheric SO42− also comprises a major component of fine particulate matter mass in urban regions, affecting visibility and public health. However, the scientific understanding of the climatic and environmental impacts of SO42− aerosols is low, because there are multiple sources of sulfur in the atmosphere, including anthropogenic and natural sources, and there are many unknowns about the atmospheric chemical reaction processes involved in aerosols formation.
Stable isotope composition is an effective new indicator to track the origin of sulfur and atmospheric chemical reactions. Particularly, the mass-independent fractionation (MIF) for oxygen isotopes (defined as D17O) of SO42− provides insight into sulfate formation mechanisms. I have used isotopic information of sulfur species for elucidation of the source and formation mechanisms for the stratospheric and tropospheric sulfate, by combining these observations of ice cores and atmospheric aerosols and global chemical transport models implemented with isotope tracers.
To date, I have contributed the following three scientific topics about the atmospheric sulfur cycle by using our unique isotopic measurements: (1) Missing source of atmospheric carbonyl sulfide (OCS) (Hattori et al. 2020 PNAS), (2) Identification of climate-impacting volcanism (Hattori et al. 2013 PNAS; Gautier et al. 2019 Nature Comm.), (3) Application of triple oxygen isotopes for sulfate formation pathways (Hattori et al. 2021 Science Advances; Wang et al. 2021 Atmos. Chem. Phys.; Itahashi, Hattori et al. 2022 Env. Sci. Tech.). In the presentation, I mainly introduce the recent publications of sulfate formation pathways using D17O measurements and a global chemical transport model.