Use of video imagery to test model predictions of surf heights

This paper describes a new method of estimating breaking wave heights from video images of the surf zone, and uses the method to test real-time numerical model predictions based on global and regional winds. The test site is an exposed beach on the southwest coast of the United Kingdom (Perranporth, Cornwall). Breaking wave height estimates based on the video technique are found to be accurate to at least ±30%. The model predictions show a linear correlation with video-derived wave heights with a regression coefficient of 0.82 and slope of 0.93 However individual comparisons can differ by up to a factor of 2 for wave heights around 1m, reducing to around 1.5 for a wave height of 3m. The primary causes of error are likely to be inadequate bathymetry near the coast and wind speed errors offshore.