Decoupling spatial and temporal patterns in short-term beach shoreline response to wave climate

This paper describes the use of a combined approach which merges numerical models and remote video techniques to derive the spatial and temporal patterns in short-term beach shoreline forcing-response to wave climate on a microtidal low energy sandy beach. Shorelines are obtained after applying an Artificial Neural Network (ANN) to daily raw video images. The data comprise directional hydrodynamic conditions propagated from deep water to 10 m depth and video-derived daily shorelines over the span of one year and a half. The spatial and temporal variability of the beach is split by Empirical Orthogonal Function (EOF) decomposition. Time-series exploration between EOF and wave height shows a decoupling in spatial shoreline response to wave climate with a more immediate effect in cross-shore sediment transport than in alongshore sediment transport. The first EOF which accounts for the cross-shore variability is significantly correlated with wave height averaged for the previous four days, while the second EOF which explains the alongshore beach variability correlates with the averaged waves of the previous 7 days.