On the effects of sea state on momentum flux

In recent years, there has been considerable effort spent on determining what (if any) effect the sea state has on air-sea surface fluxes. This problem has two components: the effect of wave age on fluxes in the absence of swell, and the additional effect of swell. In both situations, a lack of field data combining coincident measurements of direct fluxes and directional wave data has hindered progress.

Here we present recent eddy correlation stress measurements and coincident directional wave spectra from three field experiments: FETCH (measurements from an ASIS buoy in the Mediterranean), SWADE (from a SWATH ship in the Atlantic) and WAVES (from a tower in Lake Ontario). These data are used to address both aspects of sea state dependence. Data are found to support a wave age dependence in pure wind sea situations. Furthermore, the large parameter range of the combined data set allows us to study the effect of self-correlation of the variables. The effect of swell on momentum flux will also be investigated.