An empirical method to identify breaking waves

Um método empírico para identificar arrebentação de ondas

ABSTRACT

In this paper we propose a method to identify breaking waves in shallow water. The method takes the local surface elevation time series and creates a new time series computed from the local energy spectrum using the wavelet transform of the input signal which quantifies the frequencies typically present in breaking waves. A laboratory experiment in a random wave flume was conducted and used to test the method in three positions along the tank, where: (a) no waves were breaking; (b) about 30% of the waves were breaking; (c) and nearly all waves were breaking. The method was statistically tested for its ability to correctly identify breaking waves, using the fact that all waves passing the gauge locations along the shoaling process were visually identified and marked as breaking or nonbreaking. The method proved itself accurate for most cases, and only misses when waves are on the verge of breaking.

Keywords:
Wave breaking; Random waves; Wavelet analysis; Coastal processes