Before 2002, I was a Ph.D. student at Dalhousie University’s Department of Oceanography. My thesis, completed under the excellent supervision of Prof. A.J. Bowen, dealt with the surprisingly strong effects of energy losses on low frequency (0.005-0.05 Hz) surf-zone surface gravity waves (known as `infragravity waves’ or `surf beat’). Here are a couple of our papers showing evidence of rapid loss of infragravity energy during the Duck94 and Sandyduck experiments:
- Henderson, Stephen M. and A.J. Bowen (2002), Observations of surf beat forcing and dissipation, Journal of Geophysical Research, 107, (C11), 3193, doi:10.1029/2000JC000498.
- Henderson, Stephen M., Elgar, S. and A.J. Bowen (2001), Observations of surf beat propagation and energetics, Proceedings of the 27th International Conference on Coastal Engineering, 1412–1421.
Energy losses scaled as would be expected for bottom friction. Here’s a paper on the theory of dissipative infragravity waves:
- Henderson, Stephen M. and A.J. Bowen (2003), Simulations of dissipative, shore-oblique infragravity waves, Journal of Physical Oceanography, 33, 1722–1732.
Shameless self-promotion: Here’s an award I got for this work on the theory of dissipative infragravity waves.
During 2005, with help from Bob Guza, Steve Elgar, Tom Herbers, and Tony Bowen, I revisited this problem. We found that most of the infragravity energy lost in he surf zone is not dissipated by bottom friction, but instead is transferred to higher frequencies by conservative nonlinear triad interactions. Here’s a JGR paper on this work: