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: 1.27). 10/2010; 66(5):663-671. DOI: 10.1007/s10872-010-0054-4


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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    • "In this article, uncertainty in CO 2 flux due to transfer velocity is estimated using data from TOPEX/Poseidon for the entire year 2000. Various wind-speed-dependent CO 2 transfer velocities (Liss and Merlivat 1986; Wanninkhof 1992; Wanninkhof and McGillis 1999; Wanninkhof et al. 2009; Jacobs, Kohsiek, and Oost 1999; Nightingale et al. 2000; Nightingale, Liss, and Schlosser 2000; McGillis et al. 2001, 2004; Kuss, Nagel, and Schneider 2004; Ho et al. 2006; Weiss et al. 2007; Sweeney et al. 2007; Asher 2009; Takahashi et al. 2009; Prytherch et al. 2010; Sarma et al. 2010) and sea-state-dependent parameterizations (Frew et al. 2007; Zhao and Xie 2010) are used to calculate the uncertainty. Global distributions of air–sea CO 2 transfer velocity and flux are retrieved. "
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    • "There are more physical phenomena that affect the water-side transfer velocity and for which there have been proposed algorithms to simulate them. Such are the cases of the formation of bubbles with high wind speeds and breaking waves (Memery and Merlivat, 1985; Woolf, 1997, 2005; Zhao et al., 2003; Duan and Martin, 2007), wave field (Taylor and Yelland, 2001; Oost et al., 2002; Fairall et al., 2003; Hwang, 2005; Zhao and Xie, 2010), rain (Ho et al., 2004; Zappa et al., 2009; Turk et al., 2010), surfactants (Frew et al., 2004) and the variability of the wind velocity over longer time intervals (Wanninkhof, 1992). The parameterization by Fairall et al. (2000) attempts to congregate the fundamental environmental factors over the open ocean. "
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