Abstract
Water particle velocities and suspended sand concentration near the bed were measured just outside the breaker zone of the Ajigaura coast facing the Pacific Ocean. Data were obtained for 1 hour under the condition that wind waves were superimposed on swell. It was found that the low-pass-filtered concentration had strong correlation with the energy level of the incident wave. The transport of sand by the long wave component was in the offshore direction. The bottom shear stress and the pore-water pressure were estimated taking the wave atiltness into account. The sand concentrations in half wave periods had correlation with the bottom shear stress of the previous wave but less correlation with the pore-water pressure variation. The long wave component in the sand concentration was found to be simulated by a numerical model based on one dimensional diffusion equation.
