First laboratory study of air–sea gas exchange at hurricane wind speeds

Abstract

In a pilot study conducted in October and November 2011, air sea gas transfer velocities of the two sparingly soluble trace gases hexafluorobenzene and 1,4- difluorobenzene were measured in the unique high-speed wind-wave tank at Kyoto University, Japan. This air sea interaction facility is capable of producing hurricane strength wind speeds of up to u10 = 67ms-1. This constitutes the first lab study of gas transfer at such high wind speeds. The measured transfer velocities k600 spanned two orders of magnitude, lying between 11 cmh-1 and 1180 cmh-1 with the latter being the highest ever measured wind-induced gas transfer velocity. The measured gas transfer velocities are in agreement with the only available data set at hurricane wind speeds (McNeil and D Asaro, 2007). The disproportionately large increase of the transfer velocities found at highest wind speeds indicates a new regime of air sea gas transfer, which is characterized by strong wave breaking, enhanced turbulence and bubble cloud entrainment. © Author(s) 2014. CC Attribution 3.0 License.