Currents in the Coastal Area of Suo-Oshima Island near the Strong Tidal Currents of Obatake-Seto

Abstract

Obatake-Seto, located in Inlandsea of Japan, is famous for its strong tidal currents, the maximum speed of which is about ±6–7 kn (positive indicates an eastward flow, and negative, westward). The Komatsu-Ko port area is located at the northwest side of Suo-Oshima Island. The currents around this area, which have a speed of about 0.5–1.5 kn, are caused by the currents of Obatake-Seto, and the speed and direction of these currents have complex characteristics due to the area’s terrain. To clarify these characteristics, we investigated the current speed and direction, over a period of approximately one month, at three stations in the Komatsu-Ko port area. Measurements were made using an Acoustic Doppler Current Profiler “ADCP” or electromagnetic current meters at each station. From these observations, phase differences between the main currents and local currents, at the spring and neap tide periods, as well as the presence of counter currents were identified.