Backscattering of wide-band HF signals from evolving ocean-like surface: 2-D direct numerical simulations and analysis

Direct numerical simulations are used to calculate wide-band HF radar backscatter from evolving ocean-like surfaces in 2-D space. With the attainable spatial resolution of about 15 m, the large-scale wave pattern is visible in range-time plots of backscatter magnitude. The double Fourier transform of the signal magnitude or power in range and time reveals strong harmonics located along the dispersion curve of the propagating long waves. The signature is not predicted by the 1^st-order Small Perturbation Method, and considering the next, 2^nd order is required. It is shown that the spectral components along the expected dispersion curves in the ω-K domain can be used to retrieve the deterministic wave height of the surface.