A Practical bi-parameter formula of gas transfer velocity depending on wave states

Physical Oceanography Laboratory, Ocean University of China, Qingdao, 266100 China
Journal of Oceanography (Impact Factor: 1.46). 10/2010; 66(5):663-671. DOI: 10.1007/s10872-010-0054-4

ABSTRACT The parameter that describes the kinetics of the air-sea exchange of a poorly soluble gas is the gas transfer velocity which
is often parameterized as a function of wind speed. Both theoretical and experimental studies suggest that wind waves and
their breaking can significantly enhance the gas exchange at the air-sea interface. A relationship between gas transfer velocity
and a turbulent Reynolds number related to wind waves and their breaking is proposed based on field observations and drag
coefficient formulation. The proposed relationship can be further simplified as a function of the product of wind speed and
significant wave height. It is shown that this bi-parameter formula agrees quantitatively with the wind speed based parameterizations
under certain wave age conditions. The new gas transfer velocity attains its maximum under fully developed wave fields, in
which it is roughly dependent on the square of wind speed. This study provides a practical approach to quantitatively determine
the effect of waves on the estimation of air-sea gas fluxes with routine observational data.

KeywordsGas transfer velocity-wind speed-wind wave-significant wave height

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