Transient tracers and air‐sea gas transfer

This paper provides a review of the physics and chemistry associated with air‐sea gas transfer of transient atmospheric trace gases and the available laboratory and field measurement techniques used to study air‐water gas transfer. The mechanistic principles and their relation to the measurement techniques are used to show that the error associated with estimating air‐sea transfer velocities of transient tracers from transfer velocities measured using proxy tracers can be significant if an incorrect dependence of the transfer velocity on molecular diffusivity is assumed. Bubble‐mediated transfer processes are also demonstrated to have a significant effect on the parameterization of the transfer velocity.