Abstract:
This study aims to investigate the changes in the infragravity wave energy under partial
short-wave breaking conditions induced by a longshore bar. Field observations of near-bottom
pressure records on a cross-shore array were analysed for such purpose. The bispectrum was
employed to detect the phase-coupling between short and infragravity wave frequencies. This allowed
to separate the infragravity wave energy in bound and free energy components.
The bar crest induced a decrease on the short-wave energy due to depth-induced breaking. At the
same location, a damping on the bound infragravity wave energy was observed. This damping
coincides with a negative value of the short-wave radiation stress cross-shore gradient. This provides
evidence that bound infragravity wave energy decreases with a reduction in the forcing.
