沿岸域における混合過程と水理環境に関する研究： 内部潮汐と混合現象.

Transport processes in coastal oceans are important for understanding mass transport between land and ocean. Investigations of mixing processes are essential to reveal the transport processes. This paper presents mixing processes due to internal tides and the associated mass transport, on the basis of field observations and numerical simulations conducted by the author who is a recipient of Okada Prize from the Oceanographic Society of Japan, 2022. The Yoing Ocean Data Acquisition (YODA) Profiler, has been developed to observe small scale dynamics and mixing processes in coastal oceans. Results from the profiler revealed mixing in river plumes and breaking of nonlinear internal tides on a shallow slope. Breaking of internal tides results in strong turbulent mixing, sediment resuspension and generation of intermediate nepheloid layers in Otsuchi Bay, Japan. It was found that vertical mixing was enhanced by a collision of a receding internal tide and a subsequent run-up nonlinear internal bore on a gentle slope. In addition, numerical models were developed to investigate internal tides breaking. Large scale oceanic numerical models showed enhanced diurnal internal tides caused by a resonance of Kelvin waves around islands over the Izu-Ogasawara Ridge and strongly enhanced the internal tide energy flux toward the upstream of the Kuroshio owing to an interaction of the Kuroshio and tides. This study also applies methods established in oceanic studies to analysis of mixing processes in a lake. [ABSTRACT FROM AUTHOR]