Relationship between Wave Height and Sampling Interval: Revisiting Individual Wave Analysis Method

Abstract

Wave height is one of the most important physical factors in the coastal environment. In general, it is estimated using water surface elevation (WSE) data from approximately 20-30 minutes of observation. Wave height and period have typically been estimated by individual wave analysis and/or spectral analysis. When designing coastal structures, the wave parameters based on the individual wave analysis are used. However, in the case of short-period waves, the number of the WSE data becomes very small, and the wave height also decreases due tothe limitations of the individual wave analysis. In this study, the relationship between wave height and sampling interval is analyzed using statistical simulation and in situ WSE data. Using the conventional range method, the wave hieghts are underestimated by approximately 6-36% as the sampling interval, At, decreases. The Goda three-point method contributed to the wave height correction estimated by the range method. However, the optimal fitting method also shows unbiased wave height estimation. Based on the assumption that WSE consists of wave signal and non-wave noise components, the conventional range method results in underestimation of the short-period waves and overestimation of long-period waves.