Impact of modifying the wind stress to include high resolution sea surface temperature and ocean currents

Traditionally, the wind stress over the ocean has been estimated independent of the state of the ocean. Recently published research suggests that estimating the surface wind stress as a function of the atmospheric winds alone is incomplete, and that the wind stress is impacted by air-sea interaction. This paper examines the impact of small-scale sea surface temperature (SST) and wind-current shear in the wind stress formulation with a focus on changes in the mean and variability of the wind stress magnitude, eddy kinetic energy (EKE), wind work and mesoscale eddy properties. The inclusion of fine resolution SST in the wind stress parameterization, which modifies the atmospheric boundary layer stability, increases the wind stress magnitude across the North Atlantic and Pacific subpolar gyres, the Antarctic Circumpolar Current region and parts of the tropics. The additional inclusion of wind-current shear largely negates the previous stress increases over most of the ocean compared to traditional estimates. The inclusion of fine resolution SST and wind-current shear in the wind stress formulation reduces the total number of ocean eddies. The wind stress change has a larger impact on stronger eddies, as measured by a larger decrease in the eddy rotational velocity. The wind stress change results in a reduction of the basin averaged EKE. We note modest improvements in the realism of the simulated surface EKE compared to EKE computed from surface drifters in the Kuroshio, Gulf Stream and Agulhas Retroflection regions. Mean globally integrated work on the geostrophic circulation of .86-1.20 TW is consistent with previous published estimates. The root mean square work variability is significantly smaller than the mean work, except at the latitude of the energetic northern hemisphere western boundary currents (approximately 35°N), where the work variability is nearly as large as the work itself.