The mechanisms of gas exchange at the air-ocean interface are of
considerable importance in estimating fluxes of gas absorbed or released by the
ocean. This interfacial gas transfer is very complex. The air and the water
are usually in turbulent motion, and the interface between them is irregular,
and disturbed by waves, sometimes accompanied by breaking, spray and bubble
formation. Thus the transfer involves a wide variety of physical phenomena
occurring over a wide range of scales. A major goal is to develop links
between the atmospheric wind stress, surface wave field, near-surface flow,
surfactant films, and gas transfer. Surfactants have a first-order effect on
the gas transfer velocity-wind speed relationship up to moderate wind speeds
and the surface mean-square-wave slope offers a very good parameterization of
gas transfer velocity. Simultaneous measurements of these parameters are needed
to determine mechanisms involving Marangoni viscoelastic damping of waves and
In this talk, an independent method of estimating the in-situ flux of biogenic gases will will be presented. Recent field evaluation of systems designed to directly measure the flux of CO2 using the eddy correlation method and DMS using the atmospheric profile technique have been performed. During these field tests, flux estimates were combined with measurements of the air-sea concentration difference to determine the transfer coefficients in coastal waters. The success of these field tests indicate that these methods would enable investigations of a number of the physical processes controlling air-sea gas exchange.
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