Transfer of SO, and other reactive gases across the air-sea interface’

Using results obtained from experimental studies of the atmospheric transport of sensible heat, water vapour and momentum over the sea, deposition velocities of sol-uble and raactive trace gases are evaluated. The deposition velocities that result vary with the height of observation; they are nearly linearly dependent upon wind speed and are a function of the prevailing stability regime. In near-neutral stratification, i t appears best to take the deposition velocity to be about 0.13 % of the wind speed when observations are made at 10 m height. When data are collected at 1 m height, this factor becomes about 0.2 ”/. Although the evaluations are intended to apply particu-larly to the case of SO, transfer, consideration of the molecular diffusivities of other gases that are similarly reactive (e.g., NH,, HCl, NO, and SO,) suggests that less than 10 yo error will result from adopting the present results for SO, for these gases as well. When the liquid phase resistance is important, as is the case for CO, for example, then the deposition velocities are decreased to a limiting lower value specific for each gas. The present model considers only the simpler case in which the liquid phase resistance is negligible. 1