Inch, K.; Davidson, M.; Masselink, G., and Russell, P., 2016. Accurate estimation of wave reflection on a high energy, dissipative beach. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 877–881. Coconut Creek (Florida), ISSN 0749-0208.
Noise induced error in estimated wave reflection coefficients using an array method is investigated using simulated time series of water surface elevation with known reflection coefficients and added uncorrelated noise. Reflection coefficients are found to be increasingly overestimated with the addition of noise and this positive bias is more significant for lower levels of true reflection. Coherence between the water surface elevation time series changes systematically with the bias and, along with the estimated reflection coefficients, is used to create a “look-up table” which serves as a function to correct for the observed bias. Bias and corresponding coherence levels are found to be independent of frequency allowing the same correction function to be applied across all frequencies and for frequency-averaged (e.g., across the infragravity band) reflection coefficients. Root-mean-square error associated with infragravity-averaged reflection coefficients, across all known reflection levels and noise-to-signal ratios up to 1, is reduced from 0.22 before the correction to 0.01 following the correction. Field data from a natural, dissipative beach is used to demonstrate the application of these results.