The relationship between ocean surface turbulence and air-sea gas transfer velocity: An in-situ evaluation

Although the air-sea gas transfer velocity k is usually parameterized with wind speed, the so-called small-eddy model suggests a relationship between k and ocean surface dissipation of turbulent kinetic energy ϵ. Laboratory and field measurements of k and ϵ have shown that this model holds in various ecosystems. Here, field observations are presented supporting the theoretical model in the open ocean. These observations are based on measurements from the Air-Sea Interaction Profiler and eddy covariance CO₂ and DMS air-sea flux data collected during the Knorr11 cruise. We show that the model results can be improved when applying a variable Schmidt number exponent compared to a commonly used constant value of 1/2. Scaling to the viscous sublayer allows us to investigate the model at different depths and to expand its applicability for more extensive data sets.