DECADAL MORPHOLOGICAL BEHAVIOR FROM LONG-TERM BATHYMETRICSURVEYS ALONG THE BEACHES OF ANGLET USING EIGENFUNCTIONANALYSIS

摘要

Important beach retreat has been observed for decades in the coastal area of Anglet. Thus,rnthe understanding and prediction of coastal behavior over a time span of decades have become arnpriority for the conurbational council of Bayonne Anglet Biarritz. The first step towards increasingrnthe knowledge of the behavior of the beaches of Anglet, is to study historical data and EmpiricalrnOrthogonal Function (EOF) analysis has become an established technique for investigating temporalrnbeach level fluctuation. So Geographical Information Systems (GIS) were used to create digitalrnmodels of the seabed from historical survey data and EOF was performed on 25 maps, for datesrnbetween 1979 and 2002 in order to identify trends or cyclic behavior in the beach morphology. Nornclear long-term trends were observed, however some interesting observations were made. Thus, twornsignificant systems of beach behavior were underscored and the availability of EOF to study thernbehavior of the dredging spoil has been pointed out.