THE ANALYSIS OF WAVE, CURRENT AND SEDIMENT TRANSPORT AFFECTED BY TYPHOON IN THE SURF ZONE OF MIYAZAKI COAST

Abstract

 Field data of waves and nearshore currents were obtained in Miyazaki Coast due to 5 typhoons which consecutively impacted the coast in 2014. Strong northward currents as well as infragravity motions with periods 30-300 seconds were generated by typhoon waves incident mainly from the south. The characteristics of the motions were closely related to typhoon tracks. Longshore sand transport was estimated on the basis of breaker heights and longshore current velocities. The northward transport of more than 500,000m³ estimated by waves and currents was consistent with bathymetry surveys but in the opposite direction to the long-term southward transport. It was confirmed that the characteristics of sediment transport largely depended on the typhoon property. Alongshore rhythmic nearshore topography developed after 5 typhoons was suggested to be related to the edge waves propagating alongshore.