A new method to determine directional spectrum of sea waves and its application to wave buoys

A new method is proposed that uses wave elevation and slope measurements in two mutually perpendicular directions to obtain the missing data on the wave curvature needed to determine the full directional spectra of waves in the form of nine coefficients of Fourier series proposed by M.S. Longuet-Higgins and A.A. Sveshnikov. The method description is provided, along with the results of its theoretical and experimental research made in a wave basin. Experimental studies have shown similar results with theoretical calculations, taking into account the instrumental error of measuring instruments. The method errors depending on the sampling interval, wave steepness, and various wave conditions are estimated. Based on these studies the total error in measuring the wave directional spectrum with the proposed method is estimated. In addition, the estimation of the measurement error of the directional spectrum using the proposed method based on measurements made by traditional wave buoy was carried out. The proposed method can also be applied in wire wave probes.