Description of littoral, alongshore sediment movement from empirical eigen‐function analysis

TLDR: In this article, measurements of 18 closely spaced beach profiles spanning Warilla Beach, NSW over a 5-year period have been examined for alongshore exchanges in beachface configuration Horizontal slices of beach corresponding with berm, upper swash, upper and lower intertidal zones were examined by empirical orthogonal function (EOF) analysis.

Abstract: Measurements of 18 closely spaced beach profiles spanning Warilla Beach, NSW, over a 5‐year period have been examined for alongshore exchanges in beachface configuration Horizontal slices of beach corresponding with berm, upper swash, upper and lower intertidal zones were examined by empirical orthogonal function (EOF) analysis The first four EOF's for each of the four slices contain over 90% of the total variance for each slice In each instance the first eigen‐function mode represents the onshore‐offshore component of beach response, and accounts for 50 to 60% of the variance Subsequent modes describe alongshore exchange of sediment associated with large, standing, cellular water circulations of the embayment Sediment shunts along each horizontal slice are determined by identification of nodal points in the eigen‐functions These represent pivotal points through which sediment is transferred The patterns of exchange vary considerably from slice to slice, reflecting change in the dominan