鳥取砂丘海岸の海底地形の変化

The present study deals with a short-term change of an offshore bar topology along Tottori coast during 5 years (2004-2009). This coast has a multiple offshore bar system. An inner bar lies around 100m offshore and an outer bar lies between 250m and 500m offshore. The outer bars have crescentic feature with an offshore convexity. Wave lengths of the outer bar are 500m ~ 1000m and shows small yearly change. The shore line has a cusping feature. Their wave lengths are 300m ~ 450m. Inner bars also show crescentic feature in winter. The wave length ratio of cusp and inner bar to outer bar is roughly 1: 1:2. In early winter, amplitude of the outer bar reduces and in the late winter, it grows again. The difference reaches to 100m. This change seems corresponding to the integrated incident wave energy.