Working at the Scripps Institution of Oceanography with Prof. R.T. Guza in 2004, I studied the refraction of swell frequency (0.05-0.15 Hz) surface gravity waves by low frequency (0.001-0.05 Hz) surf zone motions such as shear and infragravity waves. With help from Steve Elgar and Prof. Tom Herbers, we found that this refraction accounts for much of the anomalously high directional spread of surface gravity waves observed in the surf zone during the Sandyduck field experiment. Here’s a paper on this work: