2012 Fiscal Year Final Research Report

A field study of shore break characteristics on beaches of a fringing reef

Research Project

Project/Area Number	22500990
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Single-year Grants
Section	一般
Research Field	Geography
Research Institution	Daito Bunka University
Principal Investigator	AOKI Hisashi 大東文化大学, 経営学部, 准教授 (30423742)
Project Period (FY)	2010 – 2012
Keywords	海岸地形学 / サンゴ礁 / 裾礁 / 砕波波高 / 遡上波到達高度 / 波高減衰 / 沖縄
Research Abstract	Field observations were carried out on beaches of a fringing reef in Okinawa Island, Japan to investigate the relationship between the shore break height (the height of final breaking waves near the shoreline), the reef width and wave height at the reef edge. A supplementary laboratory experiment was also conducted. The ratio of the shore break height to the wave height at the reef edge, Hb/H’, which denotes the degree of the reduction of wave height on a reef, was found to decrease with increasing reef width, W, and to decrease with decreasing water depth at the reef edge, h. Data analysis showed that Hb/ H’decreases with increasing W/h. This result indicates that the reduction of wave height on a reef is greatly controlled by morphological featuresof a fringing reef.