A novel method for tracking individual waves in the surf zone

Abstract

A new method to obtain information on individual waves as they travel shoreward is described. The wave-tracking method involves analysis of synchronous water level records obtained from a shore-normal transect of pressure transducers (PTs). The method is illustrated here using data from field deployments inside the surf zone, although the method could equally be applied outside the surf zone. As a wave travels shoreward along the instrument transect it appears in the PT records at a progressively later time. Serial cross-correlation techniques are used to shift each record in time so that each wave in the first record aligns approximately with the corresponding wave (if it exists) in subsequent records from along the transect. A local minima analysis [Power et al., 2010] is used to delimit individual waves in each record and then parameters of interest can be determined for each wave at each PT location. The wave tracking method provides the evolution of these parameters for a single wave as it travels to shore, and they can be analysed as a function of distance or local water depth. The utility of the method is illustrated with case studies including the evolution of wave height and the evolution of the ratio of wave height to water depth for surf zone waves.