Observations of the structure of turbulent mixing across the Kuroshio

Abstract

The mean structure of turbulence intensity across the Kuroshio in spring is presented by compositing microstructure profiles on a stream coordinate. The composite mean of turbulent energy dissipation rate was high near fronts on both cyclonic and anticyclonic sides. On the cyclonic side, > 10 -8 Wkg -1 (vertical diffusivity of>3×10 -5 m 2 s -1) was observed in the region of strong vertical shear of geostrophic velocity. Depth-averaged within the depth range 50-150m (150-250m) was significantly higher at 0 to 50km (-25 to 50km) compared with>50km from the axis. Although lower than on the cyclonic side, at depths of 50-150m on the anticyclonic side near the front was again enhanced. On this side, the total vertical shear of horizontal velocity was strong, whereas the geostrophic shear was weak. © 2012. American Geophysical Union. All Rights Reserved.