Variation of air--water gas transfer with wind stress and surface viscoelasticity
Frew, Nelson M.
Bock, Erik J.
McGillis, Wade R.
Karachintsev, Andrey V.
air-sea gas exchange | wind stress | surface viscoelasticity
Previous parameterizations of gas transfer velocity have attempted to cast
this quantity as a function of wind speed or wind-stress. This study demonstrates
that the presence of a surface film is effective at reducing the gas
transfer velocity at constant wind-stress. Gas exchange experiments were
performed at WHOI and UH using annular wind-wave tanks of different
scales. Systematic variations of wind-stress and surfactant concentration
(Triton-X-100) were explored to determine their influence on gas transfer
velocity. Attempts to characterize the surface properties of the surfactant
solutions were performed using mechanically generated capillary-wave
packets. Results indicate a strong inverse relationship between gas transfer
velocity and enhanced wave damping.