Observation of Upper-Ocean Mixing in the Region West of the Luzon Strait in Spring

Abstract

Abstract Zhang, S.; Xie, L; Cao, R., and Zhao, H., 2012. Observation of upper ocean mixing in the region west of the Luzon Strait in spring. The west Luzon Strait is a hot spot where water and energy exchange is strongly influenced by the westward intrusion of Kuroshio water. Shipboard observations carried out during spring 2010 quantify the upper-ocean mixing in the region west of the Luzon Strait. The observations indicate that strong turbulent mixing occurs in the upper 300 m near the Luzon Strait, where turbulent kinetic energy dissipation rates increase to magnitude of about O(10−6 W kg−1) and turbulent eddy diffusivity reaches O(10−2 m2 s−1). This enhanced mixing is plausibly associated with shear instability of the Kuroshio intrusion. As important as the internal tides and wind forcing emphasized in the classical paradigm, our observation implies also that an unstable current such as the Kuroshio intrusion may be an energy source for enhanced ocean mixing. The dependency further shows that dissipat...