Recorded presentation11B.1
Parameterization of gas exchange from the southern ocean gas exchange experiment
Alejandro Cifuentes-Lorenzen, University of Connecticut, Groton, CT; and C. J. Zappa, L. Bariteau, J. B. Edson, W. McGillis, and C. W. Fairall
Momentum, mass and heat are transferred across the air-sea interface mediating the biogeochemical cycling processes that facilitates life on earth. A particular relevant process is the carbon transfer between atmosphere and ocean via the exchange of CO2. A micrometeorological approach is taken in order to parameterize the gas transfer velocity (k) under a variety of atmospheric and oceanic conditions due to wind speeds ranging up to 20 m/s. CO2, momentum and heat fluxes are calculated via the direct covariance method and analyzed versus different atmospheric forcing. This process captures the physical variability in the transfer velocity due to different atmospheric states, particularly as a function of wind speed. As successful as this approach is, it is not complete because it ignores the role played by surface waves and the state of the ocean in the gas transfer process. Surface waves play an essential role in the transfer of momentum across the air-sea interface and evidence for a wave-coherent heat transfer has been recently presented. Therefore it is logical to include and analyze the ocean surface layer in the CO2 gas transfer process. It is assumed that the limiting step for the transfer occurs at the viscous micro-layer located at the air-sea interface, therefore analyzing how the ocean turbulence affects/disrupts this viscous layer is key to develop a phenomenological understanding of the transfer process. Directional spectra of the wave field, significant wave height, whitecap coverage and breaking frequency are analyzed versus transfer velocities. Our goal is to develop a CO2 transfer velocity parameterization as a function of the air-sea boundary layer state and the hydrodynamic variables affecting it.
Session 11B, In situ turbulent air-sea flux measurements, including gas exchange
Wednesday, 14 January 2009, 4:00 PM-5:30 PM, Room 128B
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