Bubble Models of Air-sea Gas Exchange, a Synthesis

Extrapolations of empirical air-sea gas transfer velocity models to an unmeasured gas, or to another water temperature, can be in error if the basis of that extrapolation is flawed. For the most well-known empirical gas transfer velocity models that do not explicitly account for bubble-mediated transfer, this is a recognized issue. On the other hand, mechanistic models - strictly enforcing a distinction between direct and bubble-mediated transfer - are hindered by an incomplete knowledge of the mechanisms of air-sea gas transfer. We describe a hybrid model that incorporates a mechanistic view ánd uses empirical data from eddy flux measurements of dimethyl sulphide (DMS) to calibrate the model. This results in simple algorithms, using oceanic whitecap coverage, which can be easily applied within schemes to calculate local, regional or global air-sea fluxes of gases.