10:00 AM - 10:15 AM
[AOS11-05] The 100 km wide 100-1000 fold enhancement in turbulent mixing caused by the Kuroshio induced mesoscale hydraulic jump in the lee of Tokara Strait
Keywords:Kuroshio, Microscale Turbulent Mixing, Tokara Strait
Recent microstructure surveys in the Tokara Strait suggested that very strong turbulent mixing occurs near seamounts and islands, and that the Kuroshio catalyzes the mixing due to diurnal and/or near-inertial internal waves by trapping these internal waves on its anticyclonic side. However, because these observations are made only at a few points using a vertical microstructure profiler, or using a tow-yo microstructure profiler only in the upstream side, it is still unclear how the Kuroshio induces turbulence when it flows through Tokara Strait. In this study, more intensive tow-yo microstructure surveys were conducted to uncover the detailed turbulence quantities through the entire path of the Kuroshio across the Tokara Strait. The five tow-yo microstructure transects reveal that the Kuroshio induces the 100 km wide vigorous turbulence of O(10-7-10-6 W kg-1) turbulent kinetic energy dissipation rates in the lee of Tokara Strait. The dissipation rates found in this region are 100-1000 times stronger than that found typically in the open ocean thermocline. More importantly, the lateral and vertical scales of the turbulent layers are found to be 100 km and a few 100 m, respectively, suggesting that the turbulence magnitude and its impacts are enormously large. In the presentation, we will show results of analyses to understand the mechanisms in more detail, which induce this strong turbulence.