Comparative study of bistatic scattering pattern of nearshore water waves impacted by underwater topography at UHF-band

Abstract

The electromagnetic (EM) scattering from nearshore water waves impacted by gradually-varied underwater topography at UHF-band is numerically investigated using the second-order small slope approximation (SSA-II). Based on the fully nonlinear Boussinesq equation solver, the sea wave-like sinusoidal-type waves are generated and simulated in the shoaling effect-impacted nearshore region using the free surface wave modeling package COULWAVE. It is found that the wave profile would be obviously deformed due to the shoaling effect when the wave propagates inshore. The rapid decrease of water depth would intensify this wave deformation. Numerical results of the normalized radar cross section (NRCS) are presented in bistatic configuration at UHF-band. The comparison of the NRCS of waves in the region of different underwater topography shows that the presence and position of the high-order harmonic peaks would be significantly changed in different topography cases. Moreover, the wave height, as well as the wavelength of water waves, would lead to different scattering patterns. Numerical results provide a qualitative perspective to investigate the impact of the nonlinear effect between water waves on EM scattering of sea waves in the nearshore region.