Author(s): Hiroaki Tanaka; Hideo Oshikawa; Akira Tai; Yuichi Hayami
Linked Author(s): Hideo Oshikawa, Akira Tai
Keywords: Turbidity; Wave; Tidal current; Turbulence; Wave breaking
Abstract: In recent years, the behavior of suspended solids (SS) in coastal areas has been investigated. However, because SS consist mostly of fine cohesive particles, their physical and chemical characteristics have not been sufficiently determined. In this study, in order to clarify the properties of SS in the neritic region in an inner bay, the effects of sea surface waves, currents, and turbulence on SS were investigated by conducting field observations in Isahaya Bay in the Ariake Sea, which is a typical enclosed sea and has the largest tidal range in Japan. Turbidity was used for the analysis as a proxy for SS because it is difficult to measure SS continuously. Spectral analysis of flow velocity, water pressure near the sea bottom, and water depth were carried out to reveal fluctuations in turbidity. The results showed that wind waves and related wave breaking were important for increasing turbidity and that the anisotropy of turbulence was strengthened by the wave breaking. Therefore, both wind waves and wave breaking should be considered adequately in the evaluation and prediction of the behavior of SS in inner bays.
Year: 2020