Air/Sea Transfer of Highly Soluble Gases Over Coastal Waters

• Published in: Geophysical Research Letters
• Main Authors: Porter, JG, Bruyn, WJ, Miller, SD, Saltzman, ES
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: eScholarship, University of California 2020
• Subjects: Meteorology & Atmospheric Sciences; North Atlantic
• Online Access: https://escholarship.org/uc/item/5fk9m9br; https://escholarship.org/content/qt5fk9m9br/qt5fk9m9br.pdf; https://doi.org/10.1029/2019gl085286

The deposition of soluble trace gases to the sea surface is not well studied due to a lack of flux measurements over the ocean. Here we report simultaneous air/sea eddy covariance flux measurements of water vapor, sulfur dioxide (SO2), and momentum from a coastal North Atlantic pier. Gas transfer velocities were on average about 20% lower for SO2 than for H2O. This difference is attributed to the difference in molecular diffusivity between the two molecules (DSO2/DH2O = 0.5), in reasonable agreement with bulk parameterizations in air/sea gas models. This study demonstrates that it is possible to observe the effect of molecular diffusivity on air-side resistance to gas transfer. The slope of observed relationship between gas transfer velocity and friction velocity is slightly smaller than predicted by gas transfer models, possibly due to wind/wave interactions that are unaccounted for in current models.