Interaction of internal waves and vortices and its effects on vertical mixing in the upper ocean

Research Summary

Vertical mixing, particularly that takes place under the surface mixed layer, is important for ecosystem and related material circulation. This study focuses on the interaction of internal waves and eddies as one of causes of mixing in the upper ocean.

The interaction would enhance mixing near the surface layer, because eddy-induced flow is usually stronger in shallower layers. However, previous studies pay their attentions to a limited area of the parameter space, and the interaction is qualitatively unclear out of this range, which often realizes in the ocean. In this study, we will investigate the interaction of internal waves and eddies in a wide parameter range and estimate possible areas of enhanced mixing due to the interaction.

Figure 1: Schematics of the interaction of internal waves and eddy. (Left) Internal waves incident on an eddy (side view), (Right) Examples of responses observed in preliminary experiments (plan view).

The plan is shown in the flow chart below.

Figure 2: Flow chart of the plan

Principal Investigator:

Tomohiro Nakamura

Institute of Low Temperature Sciences, Hokkaido University, Physical Oceanography,Lecturer

Joint Cooperator:

Kaoru Ito

Graduate School of Environmental Science, Hokkaido University, Physical Oceanography, PhD student