Abstract
Water particle velocities and suspended sand concentrations near the bed were measured outside and inside of the surf zone under the condition of swell. The cross-spectrum analysis revealed that long waves, with periods longer than 30s, formed a partially standing wave on the beach slope. The suspension of sediments had close correlations with wave groups outside of the surf zone and with breaking-wave-induced turbulence in the surf zone. The strong turbulence and suspended sand with high concentration tended to be developed when the trough of the precedent wave was low. The largest contribution to sediment flux was due to the steady component. The contribution of infragravity motion was about 10 to 20% of that of the steady component. The variations of suspended sand concentration and nearshore currents in the infragravity range had strong correlation with the envelope of the incident wave.
