Wave Energy Transformation Processes in a Low-energy Mediterranean Surf Zone

The dissipation and distribution of wave energy was investigated on a transect crossing the surf zone. The site is a fine grained, gently sloping beach near the river mouth of Fiumi Uniti, in the Upper Adriatic Sea. A method is described here to determine the frequency cut-off between the infragravity and the sea-swell frequency band, using the cross-shore evolution of the surface Energy Density Spectra (EDS). The temporal variations in infragravity levels were strongly related to those in incident wave energy, even if not affected by dissipation during the propagation. The analysis also considered the correlation between the incident wave height and the cross-shore current. The results cannot often find a confirmation with previous works, because of differences in the environmental setting, with small short-crested waves and limited tidal excursion. KEY WORDS: wave spectrum; cut-off frequency; energy dissipation; infragravity band; cross-correlation function