Open AccessFIELD INVESTIGATION OF BEACH PROFILE CHANGES AND THE ANALYSIS USING EMPIRICAL EIGENFUNCTIONS
Author(s) -
Hiroshi Hashimoto,
Takaaki Uda
Publication year - 1982
Publication title -
proceedings of conference on coastal engineering/proceedings of ... conference on coastal engineering
Language(s) - English
Resource type - Journals
eISSN - 2156-1028
pISSN - 0589-087X
DOI - 10.9753/icce.v18.84
Subject(s) - longshore drift , geology , eigenfunction , submarine pipeline , sediment transport , lag , plage , sediment , geotechnical engineering , oceanography , geomorphology , shore , physics , eigenvalues and eigenvectors , computer network , quantum mechanics , computer science
In order to investigate the response of beach profiles to incident waves, computations by the empirical eigenfunction analysis proposed by Winant et al. are performed. The analysis of the data obtained at Ajigaura Beach over three years from 1976 to 1979 indicates that beach profile changes due to longshore and onshore-offshore sediment transport are separable by the empirical eigenfunction method. The beach profile changes due to longshore sediment transport has a time lag of 12 weeks with respect to the change of wave direction at Ajigaura Beach. It was found theoretically that this time lag was due to the sand waves propagating in the longshore direction. Regarding as onshore-offshore sand transport, the second eigenfunction is associated with the beach changes due to onshore-offshore sand transport caused by the change of wave height.