Abstract
Hydrodynamic characteristics of the "Vortex of Naruto" were investigated based on the remotely sensed data. Small scale vortices caused by the fast tidal currents at the Naruto Strait were surveyed through airplane remote sensing. Large scale vortices were surveyed through multi - level remote sensing using Landsat and airplanes. Under sea information was obtained through fluid mechanical analysis aided by the hydraulic model tests. Small scale vortices were explained to be the coherent vortices in the free boundary layers between the tidal current and the dead water regions, and were revealed to cause the strong vertical water mixing at the strait. Large scale vortices were explained to be generated as the results of the amalgamation process of the small scale coherent vortices in 6 hours, and were revealed to cause the effective tidal exchange through the strait between Harima Sea and Kii Channel. Results obtained made it possible to catch the macroscopic view of the hydrodynamic
characteristics of the "Vortex of Naruto", that had not been done by the conventional field survey using boats.
