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Sulfur Dioxide Processing in Remote Marine Environments Studied in Depth

Strategic Insights

— 1 min read

A recent study conducted over the equatorial ocean during the Pacific Atmospheric Sulfur Experiment (PASE) has provided a unique opportunity to explore the principal pathways of sulfur processing in remote marine environments. Researchers from the University of California, led by I. Faloona, conducted fast airborne measurements of SO2 using the Drexel University APIMS instrument, which provided unprecedented insight into the complete budget of sulfur dioxide. The study revealed that the average heterogeneous loss rate of sulfur dioxide was found to be 0.05 h(-1), and the average dry deposition velocity was found to be 0.4 cm s(-1), about 30% lower than predicted by standard parameterizations.

Key Takeaways:

  • The study revealed that approximately 57% of the sulfur dioxide in the marine boundary layer (MBL) is lost to aerosols, 27% is subject to dry deposition, 7% is mixed into the buffer layer (BuL), and 10% is oxidized by OH.
  • Fast airborne measurements of SO2 using the Drexel University APIMS instrument provided unprecedented insight into the complete budget of sulfur dioxide.
  • The average heterogeneous loss rate of sulfur dioxide was found to be 0.05 h(-1), indicating that supermicron aerosols maintain a near-neutral pH.
  • The average dry deposition velocity of sulfur dioxide was found to be 0.4 cm s(-1), about 30% lower than predicted by standard parameterizations.
  • The yield of sulfur dioxide from DMS oxidation was found to be near unity.
  • The study concluded that the mission averages indicate a significant impact of sulfur dioxide on the marine environment.

Statistics:

  • 57% of sulfur dioxide in the MBL is lost to aerosols
  • 27% of sulfur dioxide is subject to dry deposition
  • 7% of sulfur dioxide is mixed into the BuL
  • 10% of sulfur dioxide is oxidized by OH
  • 0.05 h(-1) is the average heterogeneous loss rate of sulfur dioxide
  • 0.4 cm s(-1) is the average dry deposition velocity of sulfur dioxide
  • The yield of sulfur dioxide from DMS oxidation is near unity

Sources:

  • Journal of Atmospheric Chemistry, Sulfur dioxide in the tropical marine boundary layer: dry deposition and heterogeneous oxidation observed during the Pacific Atmospheric Sulfur Experiment
  • I. Faloona et al., University of California, Dept. of Land Air & Water Resources, Davis, CA 95616, USA
  • Springer, Van Godewijckstraat 30, 3311 Gz Dordrecht, Netherlands

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