Retrieval of Higher Order Ocean Spectral Information From Sunglint

An approach was developed to retrieve the ocean slope bispectrum, which describes the nonlinearity of the slope surface, from ocean sunglint data. The departure from Gaussianity of the ocean slope was described using an N-dimensional slope joint probability density function, which was derived using a perturbative approach. The resulting Edge-worth series had various slope cumulants and cumulant functions as series coefficients, and multidimensional Hermite polynomials as the series basis functions. The slope probability density was used to specify a series of relationships between the slope and glint cumulants and cumulant functions up to third order. These relationships were inverted to retrieve the slope third cumulant function, from which we obtained the slope bispectrum via Fourier transformation. The retrieval method was validated using synthetic 1-D ocean wave slope datasets with controlled phase correlations imposed on a subset of the wave spectrum components.