Directional Wavelet Analysis of Inhomogeneity in the Surface Wave Field from Aerial Laser Scanning Data

Abstract

Modern measurement techniques such as aerial laser scanning allow for rapid determination of the spatial variation of sea surface elevation. Wave fields obtained from such data show spatial inhomogeneity associated with the presence of wave groups. A method based on two-dimensional directional wavelet analysis is described by which such inhomogeneity can be characterized in the spatial and wavenumber domains. The directional wavelet method has been applied to aerial laser scanning measurements of nearshore wave conditions off the east coast of New Zealand?s South Island. A high level of spatial variability was observed, with evidence of ensembles of wave-group envelopes of quasi-Gaussian form. These envelopes occur, with variations in spatial location, across a range of wavelet scales and directions.