Water exchange processes between the Kuroshio and the shelf waters plays an important role on the cross shelf transport of materials from continent to the ocean. One of the physical processes contributing to the water exchange would be vertical mixing. Internal waves must be one of the important processes to arise the vertical mixing. On the other hand, the shelf break in the East China Sea is well known as the area where internal tides are predominantly developed. Energy of developed internal tides could be transferred to shorter time scale internal waves, then consequent to turbulent mixing. Indeed, short time scale internal waves frequently occur and the figure below shows one of the examples.

An example for internal waves detected in the shelf break of the East China Sea.Vertical axis is the distance from the sea floor. Horizontal axis is time in minutes. Upper panel indicates evolution of density structure and shows internal; waves with a period shorter than 10 minutes along with density inversion. Lower panel shows (blue) onshore and (red) offshore components of current velocity, suggesting vertically inversed current fields with a same time scale as the density field. The magnitude of the velocity was around 0.1 m s-1 and vertical scale was just a few tens meters, which is expected that the internal waves could contribute to the vertical mixing.