High Wind Gas exchange Study (HiWinGS): Measurements to improve air-sea gas transfer parameterizations

Models of air-sea gas exchange are highly uncertain at high wind speeds, due to a lack of reliable high-wind flux observations needed for model development. In moderate winds gas exchange is driven mostly by tangential stress and surface renewal. At higher winds, however, wave breaking and associated processes increase bubble-mediated gas transfer, and this exchange is understood to also be mediated by the chemical properties of the gas species.

For example, exchange of dimethylsulfide is not significantly enhanced (compared against carbon dioxide) at high winds due to the relatively higher solubility of the gas. Simultaneously measuring the exchange velocities (obtained from direct flux measurement and air-sea concentration gradient) for several gases over a range of solubilities, temperatures, wave spectra and wave breaking statistics, bubble and whitecap characterization, and wind speeds will enable development of high wind exchange parameterizations.

With recent technological developments in-hand, an experimental effort is underway by a collaborative group of researchers to undertake the challenge of open ocean air-sea gas exchange measurements in high wind conditions. The presentation will demonstrate the background for the effort, an expression of the capabilities for the partners involved, and outline the experimental plan of attack for the project.