Longshore Migration of Coastal Features Observed with X-Band Radar

Intertidal morphology was monitored continuously with an X-band radar at research pier HORS located in Hasaki, Japan facing Pacific Ocean. The horizontal extent of a radar image is approximately 5.6 km and hourly averaged radar images were processed to observe longshore distributions of shoreline and bar positions. Longshore mean shoreline and bar positions and their variation showed a seasonal change, which follows so-called beach-cycle. Wavy features with wavelength of several hundred meters were observed in shoreline locations at low energy periods, which migrated to the down-wave. Migration speeds show high correlation with the longshore current velocities measured at the pier. Wavy appearances were also observed in bar locations and their migrations are also correlated with the longshore velocities.