Tidal Re-Suspension Process and Analysis of SS Flux in Suonada, the Seto lnland Sea

Abstract

Fortnight field experiments at the stationary observation point in the Suonada sound，the Seto Inland Sea were carried out at the late summer, when diurnal inequality of tides is rather small like the early spring, to reveal the physical process of the environment near the basin floor. It has been recognized from the experiments that tidal currents were dominant and tidal re-suspension was induced around the spring tide and that temporary currents except tidal currents were generated and re-suspension due to such currents was not observed around the neap tide even when they were rather strong. While tidal re-suspension around the spring tide was induced quarter-diurnally relating to the tidal current speed, the semi-diurnal variation was also recognized which came in view clearly at the flood flow. To investigate such a re-suspension process more minutely, 25 hour field-experiment was carried out using a highly accurate current meter by which the current and turbidity can be measured in 16 Hz. It has been clarified that the power spectrum was larger by one and half times at the flood flow than at the ebb flow and further that the vertical turbulent flux of SS was also larger at the flood flow than at the ebb one.