Quantifying air-sea gas exchange using noble gases in a coastal upwelling zone

[摘要] The diffusive and bubble-mediated components of air-sea gas exchange can be quantified separately using time-series measurements of a suite of dissolved inert gases. We have evaluated the performance of four published air-sea gas exchange parameterizations using a five-day time-series of dissolved He, Ne, Ar, Kr, and Xe concentration in Monterey Bay, CA. We constructed a vertical model including surface air-sea gas exchange and vertical diffusion. Diffusivity was measured throughout the cruise from profiles of turbulent microstructure. We corrected the mixed layer gas concentrations for an upwelling event that occurred partway through the cruise. All tested parameterizations gave similar results for Ar, Kr, and Xe; their air-sea fluxes were dominated by diffusive gas exchange during our study. For He and Ne, which are less soluble, and therefore more sensitive to differences in the treatment of bubble-mediated exchange, the parameterizations gave widely different results with respect to the net gas exchange flux and the bubble flux. This study demonstrates the value of using a suite of inert gases, especially the lower solubility ones, to parameterize air-sea gas exchange.

[发布机构] Massachusetts Institute of Technology, Woods Hole Oceanogr. Institution Joint Program in Oceanography/Applied Ocean Science and Engineering, Woods Hole; MA; 02543, United States^1;Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole; MA; 02543, United States^2;Department of Chemistry, Wellesley College, Wellesley; MA; 02481, United States^3;Center for Ocean Solutions, Stanford University, Stanford; CA; 94305, United States^4

[关键词] Air sea flux;Coastal upwelling;Gas concentration;Gas exchange;Measurements of;Monterey Bay;Turbulent microstructure;Vertical diffusion