surf zone similarity parameter (or Irribaren number), £ = 6(H /L ) , 



where H and L are the respective deep-water wave height and wavelength. 

 Energy spectra of swash oscillations were separated into two bands (incident 

 waves with frequencies above 0.05 Hz, and an infragravity band for frequencies 

 below 0.05 Hz). For low Irribaren numbers (e.g., large incident waves or low 

 beach slope), the incident band swash was saturated. However, for low 

 Irribaren numbers the infragravity band showed no saturation, and the infra- 

 gravity energy increased with an increase in the incident wave heights. For 

 large Irribaren numbers, neither band was saturated. Thus, the infragravity 

 band was shown to dominate the swash energy for low values of £, , below 1.75 

 for this study. The dimensionless parameter (vertical significant swash 

 height divided by the offshore significant height) was found to be a good 

 parameterization of the swash process when compared to the Irribaren number. 



Huntley, D. A., Guza, R. T., and Thornton, E. B. 1981. "Field 

 Observations of Surf Beat; 1. Progressive Edge Waves," Journal of 

 Geophysical Research, Vol 86, No. C7, pp 6451-6466. 



This paper was the first to offer conclusive evidence for the existence 

 of edge waves using an alongshore array of bidirectional current meters. Pro- 

 gressive edge waves were measured by computing f-k spectra. The resolution of 

 these spectra was increased by employing the Maximum Likelihood Estimator. 

 From their observations it was evident that progressive edge waves were pres- 

 ent with significant amplitude in the surf-zone velocity field. At least 

 30 percent of the longshore current energy was in the form of progressive edge 

 waves. 



This paper reads well, not overwhelming the reader with detailed deriva- 

 tions and numerous equations, and provides sufficient information describing 

 the analysis techniques. In addition, a relatively concise but thorough 

 introduction of previous infragravity studies is included. Most of the arti- 

 cle presented and discussed the results of the field measurements, and 

 described the relative importance of the different sources of surf -beat energy 

 (i.e., progressive or standing edge waves, or leaky waves). 



Huntley, D. A. 1976. "Long-Period Waves on a Natural Beach," 

 Journal of Geophysical Research, Vol 81, No. 36, pp 6441-6449. 



This article was one of the first to provide definitive evidence for 

 edge waves at surf-beat frequencies on a natural beach. Data were obtained 

 with 3 two-component current sensors aligned along a line normal to the shore- 

 line out to 100 m offshore. Near the shoreline infragravity energy dominated 

 over the incident wave energy. The amount of infragravity energy decreased as 

 the distance from the shore increased. The observation of progressive low- 

 mode edge waves was suggested by matching the measured velocity decay and 

 phase relations to theoretical low-mode edge waves. The four lowest-frequency 

 spectral peaks agreed well with the calculated frequencies of edge waves prop- 

 agating at the cutoff frequencies for that beach. An explanation for the 

 occurrence of cutoff edge waves is that they are strongly resonant. Another 

 explanation presented is an energy exchange between cutoff modes through non- 

 linear interactions. A definite conclusion could not be made for the genera- 

 tion of these cutoff edge waves. 



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